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Sample records for bahrelghazali mio-pliocene hominids

  1. Cosmogenic nuclide dating of Sahelanthropus tchadensis and Australopithecus bahrelghazali: Mio-Pliocene hominids from Chad

    OpenAIRE

    Lebatard, Anne-Elisabeth; Bourlès, Didier L.; Duringer, Philippe; Jolivet, Marc; Braucher, Régis; Carcaillet, Julien; Schuster, Mathieu; Arnaud, Nicolas; Monié, Patrick; Lihoreau, Fabrice; Likius, Andossa; Mackaye, Hassan Taisso; Vignaud, Patrick; Brunet, Michel

    2008-01-01

    Ages were determined at two hominid localities from the Chad Basin in the Djurab Desert (Northern Chad). In the Koro Toro fossiliferous area, KT 12 locality (16°00′N, 18°53′E) was the site of discovery of Australopithecus bahrelghazali (Abel) and in the Toros-Menalla fossiliferous area, TM 266 locality (16°15′N, 17°29′E) was the site of discovery of Sahelanthropus tchadensis (Toumaï). At both localities, the evolutive degree of the associated fossil mammal assemblages allowed a biochronologic...

  2. Hypercarnivory, durophagy or generalised carnivory in the Mio-Pliocene hyaenids of South Africa?

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    Adam Hartstone-Rose

    2013-05-01

    Full Text Available Carnivorans, the members of the order Carnivora, exhibit wide dietary diversity – from overwhelmingly herbivorous species (like the giant and red pandas to species that specialise in the consumption of flesh (like the hypercarnivorous felids. Throughout the evolution of this order, many craniodental forms have emerged and gone extinct – notably the sabretooth felids that existed until the late Pleistocene. However, one carnivoran lineage, remarkable for its extreme masticatory adaptations, persists – the bone-cracking hyaenids. Three of the four extant members of this family (Crocuta crocuta, Hyaena hyaena and Parahyaena brunnea are among the most durophagous mammals to have ever lived. The fourth extant hyaenid – the aardwolf (Proteles cristatus – also exhibits impressive, although wholly different, masticatory adaptations as one of the most derived mammalian insectivores. How and when did the level of durophagy evident in extant bone-cracking hyenas evolve, and how do Mio-Pliocene hyenas compare to the extant members of the order in terms of their own dietary specialisations? An examination of the premolars of the Mio-Pliocene hyaenids from Langebaanweg, South Africa suggests that modern levels of durophagy appeared relatively recently. Results from an analysis of dental radii-of-curvature and premolar intercuspid notches suggest that these hyenas were neither bone crackers nor flesh specialists, but were dietary generalists.

  3. Mio-Pliocene aridity in the south-central Andes associated with Southern Hemisphere cold periods.

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    Amidon, William H; Fisher, G Burch; Burbank, Douglas W; Ciccioli, Patricia L; Alonso, Ricardo N; Gorin, Andrew L; Silverhart, Perri H; Kylander-Clark, Andrew R C; Christoffersen, Michael S

    2017-06-20

    Although Earth's climate history is best known through marine records, the corresponding continental climatic conditions drive the evolution of terrestrial life. Continental conditions during the latest Miocene are of particular interest because global faunal turnover is roughly synchronous with a period of global glaciation from ∼6.2-5.5 Ma and with the Messinian Salinity Crisis from ∼6.0-5.3 Ma. Despite the climatic and ecological significance of this period, the continental climatic conditions associated with it remain unclear. We address this question using erosion rates of ancient watersheds to constrain Mio-Pliocene climatic conditions in the south-central Andes near 30° S. Our results show two slowdowns in erosion rate, one from ∼6.1-5.2 Ma and another from 3.6 to 3.3 Ma, which we attribute to periods of continental aridity. This view is supported by synchrony with other regional proxies for aridity and with the timing of glacial ‟cold" periods as recorded by marine proxies, such as the M2 isotope excursion. We thus conclude that aridity in the south-central Andes is associated with cold periods at high southern latitudes, perhaps due to a northward migration of the Southern Hemisphere westerlies, which disrupted the South American Low Level Jet that delivers moisture to southeastern South America. Colder glacial periods, and possibly associated reductions in atmospheric CO 2 , thus seem to be an important driver of Mio-Pliocene ecological transitions in the central Andes. Finally, this study demonstrates that paleo-erosion rates can be a powerful proxy for ancient continental climates that lie beyond the reach of most lacustrine and glacial archives.

  4. Evidence for long-term uplift on the Canary Islands from emergent Mio Pliocene littoral deposits

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    Meco, Joaquín; Scaillet, Stéphane; Guillou, Hervé; Lomoschitz, Alejandro; Carlos Carracedo, Juan; Ballester, Javier; Betancort, Juan-Francisco; Cilleros, Antonio

    2007-06-01

    Several islands in the Canarian archipelago show marine deposits with identical fossil faunas, which are generally assigned to different glacioeustatic marine episodes: mainly Pleistocene episodes in Lanzarote and Fuerteventura, and Mio-Pliocene ones in Gran Canaria. Three fossil species ( Saccostrea chili, Nerita emiliana and Strombus coronatus) characterize all the marine deposits from southern Lanzarote, to the west and south of Fuerteventura and northeast of Gran Canaria. Three other species ( Ancilla glandiformis, Rothpletzia rudista and Siderastraea miocenica) confirm the chronostratigraphic attribution of these deposits. Other more occasional fossils (as Chlamys latissima, Isognomon soldanii and Clypeaster aegyptiacus) fit an upper Miocene and lower Pliocene age. This agrees with new K/Ar ages obtained from pillow lavas emplaced into the marine deposits (ca. 4.1 Ma in Gran Canaria, ca. 4.8 Ma in Fuerteventura) and from underlying (ca. 9.3 Ma in Gran Canaria) or overlying (ca. 9.8 Ma in Lanzarote) lava flows. The marine deposits are eroded but large continuous segments are preserved sloping gently towards the coast. Variations in the highest and the lowest elevations of the deposits apsl (above present sea level) indicate post-depositional uplift movements. Glacioeustatic causes are unlikely to be responsible for these variations on the basis of the coastal location of the deposits and their equatorial fauna characteristic of Mio-Pliocene corals. Differential uplift of the deposits across the archipelago is argued to result from the progressive seaward tilting of the islands along the insular volcanic trail marking the westward migration of hot spot head since 20 Ma. Successive westward accretion of younger volcanic edifices resulted in increasing lithostatic load of the crust with progressive (diachronous) tilting of the older edifices and their palaeo-shorelines marked by past coastal deposits.

  5. Micromammal biostratigraphy of the Alcoy Basin (Eastern Spain): remarks on the Mio-Pliocene boundary of the Iberian Peninsula

    International Nuclear Information System (INIS)

    Mansino, S.; Fierro, I.; Tossal, A.; Montoya, P.; Ruiz-Sánchez, F.J.

    2017-01-01

    The study of 13 micromammal localities in the southern section of the Gormaget ravine (Alcoi Basin, SE Spain) and another 4 localities in the northern section has allowed us to define four local biozones in the dawn of the Pliocene, possibly recording the Mio-Pliocene boundary. The great density of localities close to the Mio-Pliocene boundary has enabled us to achieve a great resolution in the biozonation of the earliest Pliocene, only comparable in the Iberian Peninsula to the record of the Teruel Basin (NE Spain). We interpret these biozones in the light ofthe Neogene Mammal units and the European Land Mammal Ages, and correlate them with other local biozones defined for the same time span in the Iberian Peninsula.

  6. Micromammal biostratigraphy of the Alcoy Basin (Eastern Spain): remarks on the Mio-Pliocene boundary of the Iberian Peninsula

    Energy Technology Data Exchange (ETDEWEB)

    Mansino, S.; Fierro, I.; Tossal, A.; Montoya, P.; Ruiz-Sánchez, F.J.

    2017-11-01

    The study of 13 micromammal localities in the southern section of the Gormaget ravine (Alcoi Basin, SE Spain) and another 4 localities in the northern section has allowed us to define four local biozones in the dawn of the Pliocene, possibly recording the Mio-Pliocene boundary. The great density of localities close to the Mio-Pliocene boundary has enabled us to achieve a great resolution in the biozonation of the earliest Pliocene, only comparable in the Iberian Peninsula to the record of the Teruel Basin (NE Spain). We interpret these biozones in the light ofthe Neogene Mammal units and the European Land Mammal Ages, and correlate them with other local biozones defined for the same time span in the Iberian Peninsula.

  7. Diverse diets of the Mio-Pliocene carnivorans of Langebaanweg, South Africa

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    Adam Hartstone-Rose

    2016-07-01

    Full Text Available The Mio-Pliocene guild of carnivorans of Langebaanweg (LBW, South Africa, is phylogenetically and ecologically diverse. Unlike modern African fauna, this fossil sample contains a large ursid; although there are mustelids, herpestids and viverrids in Africa today, some of the LBW members of those families were much larger than their modern confamilials. There were also numerous felid species, including some that possess a more sabretoothed dental morphology, as well as several species of hyaenids that were very different from their modern confamilials. Questions remain about the dietary morphospace occupied by these fossils. Which taxa were predominately durophagous and which were the most hypercarnivorous? Did the level of durophagy and hypercarnivory in the LBW taxa reach the level of specialisation found in modern carnivores? In the current study, we evaluate the dietary specialisations of all the large terrestrial LBW carnivorans through analysis of the radii-of-curvature and intercuspid notches present in the mandibular dentition. We found that the LBW carnivorans had less sharp premolars than do their modern confamilials an indication of greater durophagy. However, some families contain individuals with more extreme intercuspid notch patterns, indicating greater hypercarnivory. The ursid also possessed a suite of morphology unlike any modern carnivoran, exhibiting some morphology conducive to durophagy and some that places it functionally among the most hypercarnivorous of modern carnivorans. Thus it was likely capable of consuming high levels of both flesh and bone.

  8. Giant bunodont Lutrinae from the Mio-Pliocene of Kenya and Uganda

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    Pickford, M.

    2005-12-01

    Full Text Available Three new species of bunodont otters are described from the Mio-Pliocene of East Africa. They are provisionally attributed to the genus Sivaonyx Pilgrim, 1931. The species described are Sivaonyx soriae, nov. sp. and Sivaonyx senutae nov. sp. from the Latest Miocene Lukeino Formation (Kenya and Sivaonyx kamuhangirei nov. sp. from the Pliocene of Kazinga and Warwire (Uganda. Additional material of the species Sivaonyx ekecaman (Werdelin, 2003 is described from Sagatia, Mabaget Formation (Kenya. The systematics of the new tribe Enhydriodontini are discussed and we report the presence of evolutionary tendencies in the bunodont African otters: increase in body size, modification of the carnassial teeth. In particular in the P4/ the protocone becomes well separated from the paracone, at the same time that an anterior valley develops.Se describen tres nuevas especies de nutrias bunodontas del Mio-plioceno de Africa oriental. Provisionalmente se adscriben al género Sivaonyx Pilgrim 1931. Las especies descritas son Sivaonyx soriae nov. sp y Sivaonyx senutae nov. sp. del Mioceno final de la formación Lukeino (Kenia, y Sivaonyx kamuhangirei nov. sp del Plioceno de Kazinga y Warwire (Uganda. También se describen nuevos fósiles de Sagatia, formación Magabet (Kenia atribuibles a la especie Sivaonyx ekecaman (Werdelin, 2003. Se discute la sistemática de la nueva tribu Enhydriotini y se señala la presencia de dos tendencias evolutivas en las nutrias bunodontas africanas: incremento de talla y modificación de las carniceras. Especialmente del P4/ en el que el protocono se va separando del paracono, al mismo tiempo que se desarrolla un valle en posición anterior.

  9. Magnetic record of Mio-Pliocene red clay and Quaternary loess-paleosol sequence in the Chinese Loess Plateau

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    Yougui Song

    2018-02-01

    Full Text Available This article presents magnetic data of a 300-m-thick Mio-Pliocene red clay and Quaternary loess-paleosol sequence near Chaona town in the Central Chinese Loess Plateau. Detailed magnetostratigraphy shows that the aeolian red clay began to accumulate at ca. 8.1 Ma. Here, we presented a high-resolution rock magnetic data at 20–40 cm intervals within 4.5–8 ka span per sample of this section, which has been published in Song et al. (2014 [1] and (2017 [2]. The dataset including the following magnetic parameters: mass magnetic susceptibility (χ, frequency-dependent susceptibility (χfd, saturation magnetization (Ms, saturation remanent magnetization (Mrs, coercive force (Bc, remanent coercivity (Bcr, saturation isothermal remanent magnetization (SIRM and S-ratio. Magnetic susceptibility and hysteresis parameters were measured at Lanzhou University and Kyoto University, respectively. This data provides a high-resolution rock magnetic evidences for understanding East Asia Monsoon change, Asian interior aridification and tectonic effect of the uplift of the Tibetan Plateau since middle Miocene period. Keywords: Rock magnetic record, Late Miocene and Pliocene red clay, Quaternary loess-paleosol sequence, Chinese Loess Plateau

  10. Multiple tectonic mode switches indicate short-duration heat pulses in a Mio-Pliocene metamorphic core complex, West Papua, Indonesia

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    White, L. T.; Hall, R.; Gunawan, I.

    2017-12-01

    The Wandaman Peninsula is a narrow (2 km) promontory in remote western New Guinea. The peninsula is almost entirely composed of medium- to high-grade metamorphic rocks considered to be associated with a Mio-Pliocene metamorphic core complex. Previous work has shown that the uplift and exhumation of the core complex has potentially brought some extremely young eclogite to the surface. These might be comparable to the world's youngest (4.3 Ma) eclogites found in the D'Entrecasteaux Islands at the opposite end of New Guinea. We show that tectonic history of this region is complex. This is because the metamorphic sequences in the Wandaman Peninsula record multiple phases of deformation, all within the last few million years. This is demonstrated through methodical collation of cross-cutting relations from field and microstructural studies across the peninsula. The first phase of deformation and metamorphism is associated with crustal extension and partial melting that took place at 5-7 Ma according to new U-Pb data from metamorphic zircons. This extensional phase ceased after a tectonic mode switch and the region was shortened. This is demonstrated by two phases of folding (1. recumbent and 2. open) that overprint the earlier extensional fabrics. All previous structures were later overprinted by brittle extensional faults and uplift. This extensional phase is still taking place today, as is indicated by submerged forests exposed along the coastline associated with recent earthquakes and hot springs. The sequence of metamorphic rocks that are exposed in the Wandaman Peninsula show that stress and thermal conditions can change rapidly. If we consider that the present is a key to the past, then such results can identify the duration of deformation and metamorphic events more accurately than in much older orogenic systems.

  11. Mio Pliocene volcaniclastic deposits in the Famatina Ranges, southern Central Andes: A case of volcanic controls on sedimentation in broken foreland basins

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    Martina, Federico; Dávila, Federico M.; Astini, Ricardo A.

    2006-04-01

    A well-constrained record of Miocene-Pliocene explosive volcanism is preserved within the broken foreland of Western Argentina along the Famatina Ranges. This paper focuses on the volcaniclastic record known as the Río Blanco member of the El Durazno Formation. Three facies can be recognized in the study area: (1) massive tuffs; (2) volcaniclastic conglomerates and (3) pumiceous sandstones. These facies are interpreted as primary pyroclastic flow deposits (ignimbrites) and reworked volcanogenic deposits within interacting volcanic-fluvial depositional systems. Alternation between ignimbrites and volcanogenic sandstones and conglomerates suggest a recurrent pattern of sedimentation related to recurrent volcanic activity. Considering the facies mosaic and relative thicknesses of facies, short periods of syn-eruption sedimentation (volcaniclastic deposits) seem to have been separated by longer inter-eruption periods, where normal stream-flow processes were dominant. The volcaniclastic component decreases up-section, suggesting a gradual reduction in volcanic activity. The mean sedimentation rate of the Río Blanco member is higher (0.44 mm/year) than those obtained for the underlying and overlying units. This increase cannot be fully explained by foreland basement deformation and tectonic loading. Hence, we propose subsidence associated with volcanic activity as the causal mechanism. Volcanism would have triggered additional accommodation space through coeval pyroclastic deposition, modification of the stream equilibrium profile, flexural loading of volcanoes, and thermal processes. These mechanisms may have favored the preservation of volcaniclastic beds in the high-gradient foreland system of Famatina during the Mio-Pliocene. Thus, the Río Blanco member records the response of fluvial systems to large, volcanism-induced sediment loads.

  12. Population characteristics of extinct hominid endocranial volume.

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    Blumenberg, B

    1985-10-01

    Distribution and variation statistics of hominid endocranial volume (ECV) have been investigated. Within the interpretative constraints imposed by (very) small sample sizes, the requirements for normality are met, as are those for heteroscedasticity. A significant difference in means can be demonstrated for only two comparisons. With one exception, overall distribution characteristics differ significantly in pairwise comparisons between taxa. The coefficient of variation of ECV that characterizes a group composed of all Plio-Pleistocene gracile hominids does not support a single polytypic species interpretation of this assemblage. Significant differences in the coefficient of variation exist between all possible pairs of taxa with the exception of Homo habilis and Homo erectus.

  13. Cerebral cortices of East african early hominids.

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    Falk, D

    1983-09-09

    An endocast of the frontal lobe of a reconstructed skull, which is approximately 2 million years old, from the Koobi Fora region of Kenya appears to represent the oldest human-like cortical sulcal pattern in the fossil record, while the endocast from another skull from the same region produces an endocast that appears apelike in its frontal lobe and similar to endocasts from earlier South African australopithecines. New analysis of paleoanatomical evidence thus indicates that at least two taxa of early hominids coexisted in East Africa.

  14. Revision of the Mio-Pliocene bunodont otter-like mammals of the Indian Subcontinent

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    Pickford, M.

    2007-06-01

    Full Text Available A revision of the Enhydriodontini of the Indian Subcontinent is undertaken on the basis of previously described and recently collected bunodont otter-like fossils from the sub-Himalayan Siwalik Group. It is confirmed that, with the passage of geological time spanning the period 13 – 3 Ma, there occurred a progressive increase in body size, a reduction of the anterior part of the premolar row and an increase in degree of cheek tooth bunodonty and cusp mastoidization. Functional analysis of a snout with a partly preserved incisor battery of Enhydriodon sivalensis, reveals that it was probably a molluscivore, preying principally on bivalves, while other species of enhydriodonts were more likely to have been piscivores and cancrivores. One new species of Sivaonyx is described from the base of the Late Miocene of Pakistan. Bunodont otter-like mammals from Eurasia, Africa and North America are briefly discussed in light of the revision of the Indo-Pakistan ones. The origins and phylogenetic relationships of these mammals remains obscure. The major differences in dental anatomy indicate that these Old World otter-like mammals should not be classified in Enhydrini, but in a tribe of their own Enhydriodontini new tribe.La revisión de los Enhydriontinos del subcontinente Indio se aborda, tanto en base a los fósiles de nutrias bunodontas previamente descritos, como a los hallazgos recientemente realizados en el Grupo de los Siwaliks en el sub-Himalaya. Se confirma que durante el período de tiempo comprendido entre los 13 a 3 Ma hubo un progresivo incremento en la talla corporal, una reducción de la parte anterior de la serie premolar y un incremento en el grado de bunodoncia y mastoidización de las cúspides de los dientes. El análisis funcional de un hocico de Enhydriodon sivalensis con la batería de incisivos parcialmente conservados revela que esta especie fue parcialmente malacófaga, alimentándose principalmente de bivalvos, mientras que otras especies de enhydriontinos fueron más piscívoras y cancrívoras. En el trabajo también se describe una nueva especie de Sivaonyx procedente de la base del Mioceno Terminal de Paquistán. Los mamíferos bunodontos de tipo nutria de Eurasia, África y América del Norte son brevemente discutidos a la luz de la revisión realizada para las formas paquistaníes. El origen y relaciones filogenéticas de estos mamíferos permanecen oscuros. Las importantes diferencias en anatomía dental indican que estos mamíferos de tipo nutria del Viejo Mundo no deberían ser clasificados como Enhydrini, sino en una tribu propia, Enhydriodontini nueva tribu.

  15. Rodent faunas of the Mio-Pliocene continental sediments of the Teruel-Alfambra region, Spain

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    Weerd, A. van de

    1976-01-01

    In the large inland basin of Teruel-Calatayud the area around the town of Teruel is well known for its numerous remains of fossil mammals. They are found in Upper Miocene and Pliocene deposits, and some groups have already been studied in detail. Simultaneous with the collecting of fossil

  16. Dating of fossil hominid: problems and perspectives

    International Nuclear Information System (INIS)

    Poupeau, G.; Danon, J.; Baksi, A.K.

    1984-01-01

    The hominid dating anterior to the Homo Erectus has been based up to now on the rocks and minerals geochronology of vulcanic origem in stratigraphic relation with the fossils. Two methods are widely used, potassium-argon and uranium fission track dating. The vulcanic material dating; lava, lephra, associated with the hominid leavings show big difficults essentially connected to several types of contamination and modification. Two available examples inside the east-african rift show the probelms linked to these dating. The current progresses in the dating methods can contribute by one hand to a better utilization of the K-Ar and fisson track methods for the vulcanic materials. By other hand, with the introduction of new dating methods (thermoluminescence and electron paramagnetic resonance) will be possible to date directly whether the fossil bone itself or the associated sedimentar material. This open new perspectives in particular for every sites which are not inter-stratified with the vulcanic material. (L.C.) [pt

  17. The face of Olduvai Hominid 12.

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    Antón, Susan C

    2004-03-01

    Facial remains of Homo erectus are rare and their scarcity hinders our understanding of the variability and relationships in this taxon. Previously undescribed fragments of the peri-orbital region and unidentified matches between fragments of Olduvai Hominid 12 (OH 12) enhance comparison of the African H. erectus hypodigm. The newly reconstructed upper face and maxilla of OH 12 is most similar in size and shape to that of KNM-ER 3733, despite being as much as one million years younger than the Koobi Fora hominin. However, the posterior vault and mastoid region of OH 12 are most similar to OH 9. This combination of morphology suggests that the relationship between the Olduvai and Koobi Fora portions of the H. erectus hypodigm requires reconsideration.

  18. A new malaria agent in African hominids.

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    Benjamin Ollomo

    2009-05-01

    Full Text Available Plasmodium falciparum is the major human malaria agent responsible for 200 to 300 million infections and one to three million deaths annually, mainly among African infants. The origin and evolution of this pathogen within the human lineage is still unresolved. A single species, P. reichenowi, which infects chimpanzees, is known to be a close sister lineage of P. falciparum. Here we report the discovery of a new Plasmodium species infecting Hominids. This new species has been isolated in two chimpanzees (Pan troglodytes kept as pets by villagers in Gabon (Africa. Analysis of its complete mitochondrial genome (5529 nucleotides including Cyt b, Cox I and Cox III genes reveals an older divergence of this lineage from the clade that includes P. falciparum and P. reichenowi (approximately 21+/-9 Myrs ago using Bayesian methods and considering that the divergence between P. falciparum and P. reichenowi occurred 4 to 7 million years ago as generally considered in the literature. This time frame would be congruent with the radiation of hominoids, suggesting that this Plasmodium lineage might have been present in early hominoids and that they may both have experienced a simultaneous diversification. Investigation of the nuclear genome of this new species will further the understanding of the genetic adaptations of P. falciparum to humans. The risk of transfer and emergence of this new species in humans must be now seriously considered given that it was found in two chimpanzees living in contact with humans and its close relatedness to the most virulent agent of malaria.

  19. Selective Constraint on Noncoding Regions of Hominid Genomes.

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    2005-12-01

    Full Text Available An important challenge for human evolutionary biology is to understand the genetic basis of human-chimpanzee differences. One influential idea holds that such differences depend, to a large extent, on adaptive changes in gene expression. An important step in assessing this hypothesis involves gaining a better understanding of selective constraint on noncoding regions of hominid genomes. In noncoding sequence, functional elements are frequently small and can be separated by large nonfunctional regions. For this reason, constraint in hominid genomes is likely to be patchy. Here we use conservation in more distantly related mammals and amniotes as a way of identifying small sequence windows that are likely to be functional. We find that putatively functional noncoding elements defined in this manner are subject to significant selective constraint in hominids.

  20. Stepping out: a computer simulation of hominid dispersal from Africa.

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    Mithen, Steven; Reed, Melissa

    2002-10-01

    A succession of new discoveries and the recent application of new dating methods provide strong evidence that Eurasia was colonized soon after 2.0m.y.a. In light of this new evidence many scenarios have been proposed regarding the influence of glacial/interglacial cycles on hominid dispersal, the role of mountain chains and deserts as barriers, the significance of land bridges and the possibility of sea-crossings. Such factors have been proposed to explain the apparent early arrival of hominids in East Asia and relatively late arrival in Europe, although the evidence in both regions remains open to various interpretations. While it is relatively easy to propose environmental factors that may have influenced dispersal patterns, it is more difficult to evaluate such proposals and to establish what the combined impact of several factors might have been. Moreover, the role of historical contingency in creating the observed pattern of dispersal has yet to be considered. This paper describes a computer simulation model of hominid dispersal which seeks to provide a means to evaluate environmental and ecological factors in hominid dispersal. It creates probability distributions for arrival dates at six key localities and compares these with current estimates from the archaeological and fossil records. It uses these to support some of the current arguments about dispersal and to challenge others.

  1. Enamel hypoplasia in the middle pleistocene hominids from Atapuerca (Spain).

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    Bermúdez de Castro, J M; Pérez, P J

    1995-03-01

    The prevalence and chronology of enamel hypoplasias were studied in a hominid dental sample from the Sima de los Huesos (SH) Middle Pleistocene site at the Sierra de Atapuerca (Burgos, northern Spain). A total of 89 permanent maxillary teeth, 143 permanent mandibular teeth, and one deciduous lower canine, belonging to a minimum of 29 individuals, were examined. Excluding the antimeres (16 maxillary and 37 mandibular cases) from the sample, the prevalence of hypoplasias in the permanent dentition is 12.8% (23/179), whereas the deciduous tooth also showed an enamel defect. No statistically significant differences were found between both arcades and between the anterior and postcanine teeth for the prevalence of hypoplasias. In both the maxilla and the mandible the highest frequency of enamel hypoplasias was recorded in the canines. Only one tooth (a permanent upper canine) showed two different enamel defects, and most of the hypoplasias were expressed as faint linear horizontal defects. Taking into account the limitations that the incompleteness of virtually all permanent dentitions imposes, we have estimated that the frequency by individual in the SH hominid sample was not greater than 40%. Most of the hypoplasias occurred between birth and 7 years (N = 18, X = 3.5, SD = 1.3). Both the prevalence and severity of the hypoplasias of the SH hominid sample are significantly less than those of a large Neandertal sample. Furthermore, prehistoric hunter-gatherers and historic agricultural and industrial populations exhibit a prevalence of hypoplasias generally higher than that of the SH hominids. Implications for the survival strategies and life quality of the SH hominids are also discussed.

  2. Palaeodemography of the Atapuerca-SH Middle Pleistocene hominid sample.

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    Bermúdez de Castro, J M; Nicolás, M E

    1997-01-01

    We report here on the palaeodemographic analysis of the hominid sample recovered to date from the Sima de los Huesos (SH) Middle Pleistocene cave site in the Sierra de Atapuerca (Burgos, Spain). The analysis of the mandibular, maxillary, and dental remains has made it possible to estimate that a minimum of 32 individuals, who probably belonged to the same biological population, are represented in the current SH human hypodigm. The remains of nine-individuals are assigned to males, and nine to females, suggesting that a 1:1 sex ratio characterizes this hominid sample. The survivorship curve shows a low representation of infants and children, a high mortality among the adolescents and prime-age adults, and a low older adult mortality. Longevity was probably no greater than 40 years. This mortality pattern (adolescents and adults); which in some aspects resembles that observed in Neandertals, is quite different from those reported for recent foraging human groups. The adult age-at-death distribution of the SH hominid sample appears to be neither the consequence of underaging the older adults, nor of differential preservation or of the recognition of skeletal remains. Thus if we accept that they had a life history pattern similar to that of modern humans there would appear to be a clear contradiction between the demographic distribution and the demographic viability of the population represented by the SH hominid fossils. The possible representational bias of the SH hominid sample, as well as some aspects of the reproductive biology of the Pleistocene populations are also discussed.

  3. South Turkwel: a new pliocene hominid site in Kenya.

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    Ward, C V; Leakey, M G; Brown, B; Brown, F; Harris, J; Walker, A

    1999-01-01

    New fossils discovered south of the Turkwel River in northern Kenya include an associated metacarpal, capitate, hamate, lunate, pedal phalanx, mandibular fragment, and teeth. These fossils probably date to around 3.5 m.y.a. Faunal information suggests that the environment at South Turkwel was predominantly bushland. The mandibular and dental remains are fragmentary, but the postcranial fossils are informative. Comparisons with Australopithecus, modern human, chimpanzee and gorilla hand bones suggest that the Turkwel hominid was most like Australopithecus afarensis and A. africanus. Carpometacarpal articulations are intermediate between those of modern humans and African apes, suggesting enhanced gripping capabilities compared with extant apes. The hamulus was strikingly large, similar in proportion only to Neandertals and some gorillas, suggesting the presence of powerful forearms and hands. There are no indicators of adaptations to knuckle-walking or suspensory locomotion in the hand, and the pedal phalanx suggests that this hominid was habitually bipedal. Copyright 1999 Academic Press.

  4. Foot bones from Omo: implications for hominid evolution.

    Science.gov (United States)

    Gebo, Daniel L; Schwartz, Gary T

    2006-04-01

    We reanalyze a hominid talus and calcaneus from Omo dating to 2.2 mya and 2.36 mya, respectively. Although both specimens occur at different localities and times, both tarsals articulate well together, suggesting a single taxon on the basis of size and function. We attribute these foot bones to early Homo on the basis of their morphology. The more modern-like tarsal morphology of these Omo foot bones makes them very similar to a talus from Koobi Fora (KNM-ER 813), a specimen attributed to Homo rudolfensis or Homo erectus. Although the Omo tarsals are a million years younger than the oldest known foot bones from Hadar, both localities demonstrate anatomical differences representing two distinct morphological patterns. Although all known hominid tarsals demonstrate clear bipedal features, the tarsal features noted below suggest that biomechanical changes did occur over time, and that certain features are associated with different hominid lineages (especially the robust australopithecines). Copyright 2006 Wiley-Liss, Inc.

  5. First record of the megatoothed shark Carcharocles megalodon from the Mio-Pliocene Purisima Formation of Northern California.

    OpenAIRE

    Boessenecker, Robert W.

    2016-01-01

    Megatoothed sharks (Family: Otodontidae) are among the most widely reported sharks in Cenozoic marine sediments worldwide, and certain species such as the famed Carcharocles megalodon are particularly abundant in Neogene deposits on the Atlantic margin of the United States. Cenozoic marine strata on the Pacific margin of North America have yielded one of the most densely sampled marine vertebrate records anywhere, but published occurrences of shark assemblages are uncommon. Rarer yet are publ...

  6. Sawfishes and Other Elasmobranch Assemblages from the Mio-Pliocene of the South Caribbean (Urumaco Sequence, Northwestern Venezuela)

    Science.gov (United States)

    2015-01-01

    The Urumaco stratigraphic sequence, western Venezuela, preserves a variety of paleoenvironments that include terrestrial, riverine, lacustrine and marine facies. A wide range of fossil vertebrates associated with these facies supports the hypothesis of an estuary in that geographic area connected with a hydrographic system that flowed from western Amazonia up to the Proto-Caribbean Sea during the Miocene. Here the elasmobranch assemblages of the middle Miocene to middle Pliocene section of the Urumaco sequence (Socorro, Urumaco and Codore formations) are described. Based on new findings, we document at least 21 taxa of the Lamniformes, Carcharhiniformes, Myliobatiformes and Rajiformes, and describe a new carcharhiniform species (†Carcharhinus caquetius sp. nov.). Moreover, the Urumaco Formation has a high number of well-preserved fossil Pristis rostra, for which we provide a detailed taxonomic revision, and referral in the context of the global Miocene record of Pristis as well as extant species. Using the habitat preference of the living representatives, we hypothesize that the fossil chondrichthyan assemblages from the Urumaco sequence are evidence for marine shallow waters and estuarine habitats. PMID:26488163

  7. New fission-track ages of mio-pliocene tuffs in the Sierras Pampeanas and Precordillera of Argentina

    International Nuclear Information System (INIS)

    Tabbutt, K.; Naeser, C.W.; Jordan, T.E.; Cerveny, P.F.

    1989-01-01

    Fission-track dates were determined for 18 volcanic tuff horizons located in nine Neogene foreland basin sequences distributed throughout the Precordillera and Sierras Pampeanas of Northwestern Argentina, an area of nearly horizontal subduction. These and other data indicate that a lower age limit for the sedimentary sequences studied is approximately 17 Ma. Therefore these fission-track dates constrain both the history of volcanic activity and the time of deposition in several foreland basins from the middle Miocene to Recent. Although the dates range from 3.6±0.8 Ma to 17.0±1.9 Ma, there is a marked increase in the number of ashes younger than 9 Ma. This implies that two distinct episodes of volcanic activity affected the region. The source of some of these tuffs is unknown but they are probably limited to the 'flat-slab' region between 27 deg and 32 deg S. Tuffs at Rio Blanco and Santa Florentina that are spatially associated with the Mogotes dacite domes of the Famatina Range represented magmatism bracketed from about 7 to 4 Ma in the region underlain by the flat-subducted plate. The stratigraphic relations in the basins show that the faulting that uplifted Sierra de Famatina was contemporaneous with the volcanism which reached the surface along the bounding faults. (Author) [es

  8. Sawfishes and Other Elasmobranch Assemblages from the Mio-Pliocene of the South Caribbean (Urumaco Sequence, Northwestern Venezuela.

    Directory of Open Access Journals (Sweden)

    Jorge D Carrillo-Briceño

    Full Text Available The Urumaco stratigraphic sequence, western Venezuela, preserves a variety of paleoenvironments that include terrestrial, riverine, lacustrine and marine facies. A wide range of fossil vertebrates associated with these facies supports the hypothesis of an estuary in that geographic area connected with a hydrographic system that flowed from western Amazonia up to the Proto-Caribbean Sea during the Miocene. Here the elasmobranch assemblages of the middle Miocene to middle Pliocene section of the Urumaco sequence (Socorro, Urumaco and Codore formations are described. Based on new findings, we document at least 21 taxa of the Lamniformes, Carcharhiniformes, Myliobatiformes and Rajiformes, and describe a new carcharhiniform species (†Carcharhinus caquetius sp. nov.. Moreover, the Urumaco Formation has a high number of well-preserved fossil Pristis rostra, for which we provide a detailed taxonomic revision, and referral in the context of the global Miocene record of Pristis as well as extant species. Using the habitat preference of the living representatives, we hypothesize that the fossil chondrichthyan assemblages from the Urumaco sequence are evidence for marine shallow waters and estuarine habitats.

  9. Sawfishes and Other Elasmobranch Assemblages from the Mio-Pliocene of the South Caribbean (Urumaco Sequence, Northwestern Venezuela).

    Science.gov (United States)

    Carrillo-Briceño, Jorge D; Maxwell, Erin; Aguilera, Orangel A; Sánchez, Rodolfo; Sánchez-Villagra, Marcelo R

    2015-01-01

    The Urumaco stratigraphic sequence, western Venezuela, preserves a variety of paleoenvironments that include terrestrial, riverine, lacustrine and marine facies. A wide range of fossil vertebrates associated with these facies supports the hypothesis of an estuary in that geographic area connected with a hydrographic system that flowed from western Amazonia up to the Proto-Caribbean Sea during the Miocene. Here the elasmobranch assemblages of the middle Miocene to middle Pliocene section of the Urumaco sequence (Socorro, Urumaco and Codore formations) are described. Based on new findings, we document at least 21 taxa of the Lamniformes, Carcharhiniformes, Myliobatiformes and Rajiformes, and describe a new carcharhiniform species (†Carcharhinus caquetius sp. nov.). Moreover, the Urumaco Formation has a high number of well-preserved fossil Pristis rostra, for which we provide a detailed taxonomic revision, and referral in the context of the global Miocene record of Pristis as well as extant species. Using the habitat preference of the living representatives, we hypothesize that the fossil chondrichthyan assemblages from the Urumaco sequence are evidence for marine shallow waters and estuarine habitats.

  10. Posterior dental size reduction in hominids: the Atapuerca evidence.

    Science.gov (United States)

    Bermúdez de Castro, J M; Nicolas, M E

    1995-04-01

    In order to reassess previous hypotheses concerning dental size reduction of the posterior teeth during Pleistocene human evolution, current fossil dental evidence is examined. This evidence includes the large sample of hominid teeth found in recent excavations (1984-1993) in the Sima de los Huesos Middle Pleistocene cave site of the Sierra de Atapuerca (Burgos, Spain). The lower fourth premolars and molars of the Atapuerca hominids, probably older than 300 Kyr, have dimensions similar to those of modern humans. Further, these hominids share the derived state of other features of the posterior teeth with modern humans, such as a similar relative molar size and frequent absence of the hypoconulid, thus suggesting a possible case of parallelism. We believe that dietary changes allowed size reduction of the posterior teeth during the Middle Pleistocene, and the present evidence suggests that the selective pressures that operated on the size variability of these teeth were less restrictive than what is assumed by previous models of dental reduction. Thus, the causal relationship between tooth size decrease and changes in food-preparation techniques during the Pleistocene should be reconsidered. Moreover, the present evidence indicates that the differential reduction of the molars cannot be explained in terms of restriction of available growth space. The molar crown area measurements of a modern human sample were also investigated. The results of this study, as well as previous similar analyses, suggest that a decrease of the rate of cell proliferation, which affected the later-forming crown regions to a greater extent, may be the biological process responsible for the general and differential dental size reduction that occurred during human evolution.

  11. Age of the earliest known hominids in Java, Indonesia.

    Science.gov (United States)

    Swisher, C C; Curtis, G H; Jacob, T; Getty, A G; Suprijo, A; Widiasmoro

    1994-02-25

    40Ar/39Ar laser-incremental heating of hornblende separated from pumice recovered at two hominid sites in Java, Indonesia, has yielded well-defined plateaus with weighted mean ages of 1.81 +/- 0.04 and 1.66 +/- 0.04 million years ago (Ma). The hominid fossils, a juvenile calvaria of Pithecanthropus and a partial face and cranial fragments of Meganthropus, commonly considered part of the Asian Homo erectus hypodigm, are at least 0.6 million years older than fossils referred to as Homo erectus (OH-9) from Olduvai Gorge, Tanzania, and comparable in age with the oldest Koobi Fora Homo cf. erectus (Homo ergaster) in Kenya. These ages lend further credence to the view that Homo erectus may have evolved outside of Africa. If the ancestor of Homo erectus ventured out of Africa before 1.8 Ma, the dispersal would have predated the advent of the Acheulean culture at 1.4 Ma, possibly explaining the absence of these characteristic stone cleavers and hand axes in East Asia.

  12. Interproximal grooving in the Atapuerca-SH hominid dentitions.

    Science.gov (United States)

    Bermúdez de Castro, J M; Arsuaga, J L; Pérez, P J

    1997-03-01

    The dental sample recovered from the Sima de los Huesos (SH) Middle Pleistocene cave site of the Sierra de Atapuerca (Spain) includes 296 specimens. Interproximal wear grooves have been observed in 20 maxillary and mandibular posterior teeth belonging to at least five of the 32 individuals identified so far in the SH hypodigm. Interproximal grooving affected only the adults, and at an age between 25 and 40 years. The appearance, morphology, and location pattern of the SH wear grooves are similar to those reported in other fossil hominids and in more recent human populations. Two alternative proposals, the toothpicking and the fiber or sinew processing hypotheses, compete for explaining the formation of this anomalous wear. The characteristics observed in the wear grooves of the SH teeth are compatible only with the habitual probing of interdental spaces by means of hard and inflexible objects. Dietary grit may also have contributed to the abrasion of the root walls during the motion of the dental probes.

  13. Taxonomic affinities and evolutionary history of the Early Pleistocene hominids of Java: dentognathic evidence.

    Science.gov (United States)

    Kaifu, Yousuke; Baba, Hisao; Aziz, Fachroel; Indriati, Etty; Schrenk, Friedemann; Jacob, Teuku

    2005-12-01

    Temporal changes, within-group variation, and phylogenetic positions of the Early Pleistocene Javanese hominids remain unclear. Recent debate focused on the age of the oldest Javanese hominids, but the argument so far includes little morphological basis for the fossils. To approach these questions, we analyzed a comprehensive dentognathic sample from Sangiran, which includes most of the existing hominid mandibles and teeth from the Early Pleistocene of Java. The sample was divided into chronologically younger and older groups. We examined morphological differences between these chronological groups, and investigated their affinities with other hominid groups from Africa and Eurasia. The results indicated that 1) there are remarkable morphological differences between the chronologically younger and older groups of Java, 2) the chronologically younger group is morphologically advanced, showing a similar degree of dentognathic reduction to that of Middle Pleistocene Chinese H. erectus, and 3) the chronologically older group exhibits some features that are equally primitive as or more primitive than early H. erectus of Africa. These findings suggest that the evolutionary history of early Javanese H. erectus was more dynamic than previously thought. Coupled with recent discoveries of the earliest form of H. erectus from Dmanisi, Georgia, the primitive aspects of the oldest Javanese hominid remains suggest that hominid groups prior to the grade of ca. 1.8-1.5 Ma African early H. erectus dispersed into eastern Eurasia during the earlier Early Pleistocene, although the age of the Javanese hominids themselves is yet to be resolved. Subsequent periods of the Early Pleistocene witnessed remarkable changes in the Javanese hominid record, which are ascribed either to significant in situ evolution or replacement of populations. 2005 Wiley-Liss, Inc.

  14. An alternative method of estimating the cranial capacity of Olduvai Hominid 7.

    Science.gov (United States)

    Vaisnys, J R; Lieberman, D; Pilbeam, D

    1984-09-01

    The cranial capacity of Olduvai Hominid 7 is estimated to be 690 cc, with a standard uncertainty range of 538 to 868 cc. The estimate is derived from a systematic consideration of the relationships between Bregma-Asterion chords and cranial capacities obtained from a large sample of Homo sapiens and Pan troglodytes and from available fossil hominids. The estimation technique is applicable to other characters and specimens.

  15. Cenozoic vegetation, climate changes and hominid evolution in tropical Africa

    Science.gov (United States)

    Bonnefille, Raymonde

    2010-07-01

    This paper reviews information on past vegetation of tropical Africa during the Cenozoic, focused upon the last 10 Ma, a time spanning hominid record in Central and East Africa. Summary of palaeobotanical data collected at terrestrial sites are compared with new results on the long term evolution of the continental vegetation zones documented from marine pollen record of two deep sea cores recovered from the Atlantic and Indian Oceans. Section 2 includes a summary of modern distribution of vegetation belts in the African continent and a synthesis of the results of both macrobotanical (fossil wood, leaves and fruits) and microbotanical (mainly pollen) studies presented according to time scale and geographical location. The main features emphasized by the palaeobotanical results are 1) seasonal vegetation and climate documented as soon as the Eocene in Tanzania 2) well diversified forests existing in northern West Ethiopia during the Oligocene 3) high temporal and spatial variabilities of forests composition during the Miocene when deciduous Legume woodland was documented in Ethiopia whereas wetter evergreen forests existed in Western Kenya 4) lack of evidence for an evergreen forest belt, continuous from Western Congo to East Africa. Section 3 presents new original pollen data recovered from a long core in the Gulf of Aden documenting large scale past vegetation changes in East Africa during the last 11 Ma. These results are discussed in comparison with a summarized long pollen sequence previously published from a marine core offshore the Niger delta. This comparison illustrates variations in geographical distribution of large vegetation zone at the continental scale, through time. In Section 4, vegetation changes registered during the last 10 Ma are discussed in relation with the results of isotopic studies and an updated presentation of hominids evolution in Africa. Several changes are shown in the marine records. An expansion of savanna/grassland is shown at 10

  16. Early hominid evolution and ecological change through the African Plio-Pleistocene.

    Science.gov (United States)

    Reed, K E

    1997-01-01

    The habitats in which extinct hominids existed has been a key issue in addressing the origin and extinction of early hominids, as well as in understanding various morphological and behavioral adaptations. Many researchers postulated that early hominids lived in an open savanna (Dart, 1925; Robinson, 1963; Howell, 1978). However, Vrba (1985, 1988) has noted that a major global climatic and environmental shift from mesic, closed to xeric, open habitats occurred in the late African Pliocene (approximately 2.5 m.y.a.), thus implying that the earliest hominids existed in these mesic, wooded environs. This climatic shift is also suggested to have contributed to a pulse in speciation events with turnovers of many bovid and possibly hominid species. Previous environmental reconstructions of hominid localities have concentrated on taxonomic identities and taxonomic uniformitarianism to provide habitat reconstructions (e.g., Vrba, 1975; Shipman & Harris, 1988). In addition, relative abundances of species are often used to reconstruct a particular environment, when in fact taphonomic factors could be affecting the proportions of taxa. This study uses the morphological adaptations of mammalian assemblages found with early hominids to reconstruct the habitat based on each species' ecological adaptations, thus minimizing problems introduced by taxonomy and taphonomy. Research presented here compares east and south African Plio-Pleistocene mammalian fossil assemblages with 31 extant mammalian communities from eight different habitat types. All communities are analyzed through ecological diversity methods, that is, each species trophic and locomotor adaptations are used to reconstruct an ecological community and derive its vegetative habitat. Reconstructed habitats show that Australopithecus species existed in fairly wooded, well-watered regions. Paranthropus species lived in similar environs and also in more open regions, but always in habitats that include wetlands. Homo is the

  17. Earliest Pleistocene hominid cranial remains from Dmanisi, Republic of Georgia: taxonomy, geological setting, and age.

    Science.gov (United States)

    Gabunia, L; Vekua, A; Lordkipanidze, D; Swisher, C C; Ferring, R; Justus, A; Nioradze, M; Tvalchrelidze, M; Antón, S C; Bosinski, G; Jöris, O; Lumley, M A; Majsuradze, G; Mouskhelishvili, A

    2000-05-12

    Archaeological excavations at the site of Dmanisi in the Republic of Georgia have uncovered two partial early Pleistocene hominid crania. The new fossils consist of a relatively complete cranium and a second relatively complete calvaria from the same site and stratigraphic unit that yielded a hominid mandible in 1991. In contrast with the uncertain taxonomic affinity of the mandible, the new fossils are comparable in size and morphology with Homo ergaster from Koobi Fora, Kenya. Paleontological, archaeological, geochronological, and paleomagnetic data from Dmanisi all indicate an earliest Pleistocene age of about 1.7 million years ago, supporting correlation of the new specimens with the Koobi Fora fossils. The Dmanisi fossils, in contrast with Pleistocene hominids from Western Europe and Eastern Asia, show clear African affinity and may represent the species that first migrated out of Africa.

  18. New hominid fossils from Member 1 of the Swartkrans formation, South Africa.

    Science.gov (United States)

    Pickering, Travis Rayne; Heaton, Jason L; Clarke, Ronald J; Sutton, Morris B; Brain, C K; Kuman, Kathleen

    2012-05-01

    Member 1 of the Swartkrans Formation is comprised of two sedimentary infills, the Lower Bank (LB) and the Hanging Remnant (HR). Together, the LB and HR preserve fossils of early Homo and Paranthropus robustus, Earlier Stone Age lithic artifacts, purported bone digging tools and butchered animal bones. Collectively, this evidence was the first to establish the co-existence of two early Pleistocene hominid species and also led to inferences of plant root harvesting and meat-eating by one or both of those species. P. robustus is the more abundant of the two hominids at Swartrkrans, represented in Member 1 by hundreds of fossils that derive from at least 99 individuals. Thus, Swartkrans Member 1 stands as the world's single largest repository of that extinct species. Here we add to the Member 1 sample of hominid fossils with descriptions of 14 newly discovered specimens. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Morphometric variation in Plio-Pleistocene hominid distal humeri.

    Science.gov (United States)

    Lague, M R; Jungers, W L

    1996-11-01

    The magnitude and meaning of morphological variation among Plio-Pleistocene hominid distal humeri have been recurrent points of disagreement among paleoanthropologists. Some researchers have found noteworthy differences among fossil humeri that they believe merit taxonomic separation, while others question the possibility of accurately sorting these fossils into different species and/or functional groups. Size and shape differences among fossil distal humeri are evaluated here to determine whether the magnitude and patterns of these differences can be observed within large-bodied, living hominoids. Specimens analyzed in this study have been assigned to various taxa (Australopithecus afarensis, A. africanus, A. anamensis, Paranthropus, and early Homo) and include AL 288-1m, AL 288-1s, AL 137-48a, AL 322-1, Gomboré IB 7594, TM 1517, KNM-ER 739, KNM-ER 1504, KMN-KP 271 (Kanapoi), and Stw 431. Five extant hominoid populations are sampled to provide a standard by which to consider differences found between the fossils, including two modern human groups (Native American and African American), one group of Pan troglodytes, and two subspecies of Gorilla gorilla (G.g. beringei, G.g. gorilla). All possible pairwise d values (average Euclidena distances) are calculated within each of the reference populations using an exact randomization procedure. This is done using both raw linear measurements as well as scale-free shape data created as ratios of each measurement to the geometric mean. Differences between each pair of fossil humeri are evaluated by comparing their d values to the distribution of d values found within each of the reference populations. Principal coordinate analysis and an unweighted pair group method with arithmetic averages (UPGMA) cluster analysis are utilized to further assess similarities and differences among the fossils. Finally, canonical variates analysis and discriminant analysis are employed using all hominoid samples in order to control for

  20. Working Memory: A Cognitive Limit to Non-Human Primate Recursive Thinking Prior to Hominid Evolution

    Directory of Open Access Journals (Sweden)

    Dwight W. Read

    2008-10-01

    Full Text Available In this paper I explore the possibility that recursion is not part of the cognitive repertoire of non-human primates such as chimpanzees due to limited working memory capacity. Multiple lines of data, from nut cracking to the velocity and duration of cognitive development, imply that chimpanzees have a short-term memory size that limits working memory to dealing with two, or at most three, concepts at a time. If so, as a species they lack the cognitive capacity for recursive thinking to be integrated into systems of social organization and communication. If this limited working memory capacity is projected back to a common ancestor for Pan and Homo, it follows that early hominid ancestors would have had limited working memory capacity. Hence we should find evidence for expansion of working memory capacity during hominid evolution reflected in changes in the products of conceptually framed activities such as stone tool production. Data on the artifacts made by our hominid ancestors support this expansion hypothesis for hominid working memory, thereby leading to qualitative differences between Pan and Homo.

  1. Evidence for widespread degradation of gene control regions in hominid genomes.

    Directory of Open Access Journals (Sweden)

    Peter D Keightley

    2005-02-01

    Full Text Available Although sequences containing regulatory elements located close to protein-coding genes are often only weakly conserved during evolution, comparisons of rodent genomes have implied that these sequences are subject to some selective constraints. Evolutionary conservation is particularly apparent upstream of coding sequences and in first introns, regions that are enriched for regulatory elements. By comparing the human and chimpanzee genomes, we show here that there is almost no evidence for conservation in these regions in hominids. Furthermore, we show that gene expression is diverging more rapidly in hominids than in murids per unit of neutral sequence divergence. By combining data on polymorphism levels in human noncoding DNA and the corresponding human-chimpanzee divergence, we show that the proportion of adaptive substitutions in these regions in hominids is very low. It therefore seems likely that the lack of conservation and increased rate of gene expression divergence are caused by a reduction in the effectiveness of natural selection against deleterious mutations because of the low effective population sizes of hominids. This has resulted in the accumulation of a large number of deleterious mutations in sequences containing gene control elements and hence a widespread degradation of the genome during the evolution of humans and chimpanzees.

  2. Dating by fission tracks in archaeology. 3. Tephrochronology and Hominid dating

    International Nuclear Information System (INIS)

    Poupeau, G.; Zuleta, E.

    1984-01-01

    Tephras (or volcanic ashes) are excellent stratigraphic tracers. Its utilization in this domain, or tephrochronology, is shortly presented. The main archaeological utilization of the tephrochronology is related with the dating of fossil hominids, there where exist the volcano-fossil sedimentar series, at Ceylon or at East-African Rift. (L.C.) [pt

  3. Lapa vermelha IV Hominid 1: morphological affinities of the earliest known American

    Directory of Open Access Journals (Sweden)

    Neves Walter A.

    1999-01-01

    Full Text Available Several studies concerning the extra-continental morphological affinities of Paleo-Indian skeletons, carried out independently in South and North America, have indicated that the Americas were first occupied by non-Mongoloids that made their way to the New World through the Bering Strait in ancient times. The first South Americans show a clear resemblance to modern South Pacific and African populations, while the first North Americans seem to be at an unresolved morphological position between modern South Pacific and Europeans. In none of these analyses the first Americans show any resemblance to either northeast Asians or modern native Americans. So far, these studies have included affirmed and putative early skeletons thought to date between 8,000 and 10,000 years B.P. In this work the extra-continental morphological affinities of a Paleo-Indian skeleton well dated between 11,000 and 11,500 years B.P. (Lapa Vermelha IV Hominid 1, or "Luzia" is investigated, using as comparative samples Howells' (1989 world-wide modern series and Habgood's (1985 Old World Late Pleistocene fossil hominids. The comparison between Lapa Vermelha IV Hominid 1 and Howells' series was based on canonical variate analysis, including 45 size-corrected craniometric variables, while the comparison with fossil hominids was based on principal component analysis, including 16 size-corrected variables. In the first case, Lapa Vermelha IV Hominid 1 exhibited an undisputed morphological affinity firstly with Africans and secondly with South Pacific populations. In the second comparison, the earliest known American skeleton had its closest similarities with early Australians, Zhoukoudian Upper Cave 103, and Taforalt 18. The results obtained clearly confirm the idea that the Americas were first colonized by a generalized Homo sapiens population which inhabited East Asia in the Late Pleistocene, before the definition of the classic Mongoloid morphology.

  4. Direct dating of hominids using ESR and U-series dating

    International Nuclear Information System (INIS)

    Gruen, R.

    1999-01-01

    Full text: Dating studies on palaeoanthropological sites is usually carried out on material associated with the human remains, such as the sediment, charcoal or other fauna rather than the human specimen itself. The reason lies in the fact that most dating techniques are destructive and because the hominid remains are too rare to be sacrificed for dating. This indirect dating approach is in many cases not satisfactory, because:(i) the human remains are often buried into the sediments and the association with other materials is uncertain (e.g. Skhul, Qafzeh, etc.);(ii) faunal remains or minerals from the sediment are re-worked from older deposits (see e.g. present discussion of the age of the Homo erectus remains in Indonesia);(iii) the hominid specimen was discovered at a time when no careful excavations were carried out and it is impossible to correlate the specimen with other datable material (nearly 90% of all palaeoanthropological specimen). For example, the hominid burial site of Qafzeh in Israel has been dated by several independent dating laboratories with a multitude of methods. However, the data are still not accepted by some because the dating has not been carried out on the hominid specimen. Until recently, hominid fossils could only be dated by radiocarbon. This method reaches back to about 40,000 years. As a consequence, all the older fossils could not be analysed and many important questions in our understanding of human evolution could not be addressed. Human remains are scarce and extremely valuable, therefore any sort of destruction has to be kept to an absolute minimum. This is of particular importance in Australia where any human fossils are sacred. Thus, for the analysis of hominid material it was necessary to develop a more or less non-destructive techniques. This has been accomplished in recent years by the application of ESR dating of tooth enamel and a combination of gamma spectrometric and TIMS U-series dating of bones. The examples of

  5. Dental size variation in the Atapuerca-SH Middle Pleistocene hominids.

    Science.gov (United States)

    Bermúdez de Castro, J M; Sarmiento, S; Cunha, E; Rosas, A; Bastir, M

    2001-09-01

    The Middle Pleistocene Atapuerca-Sima de los Huesos (SH) site in Spain has yielded the largest sample of fossil hominids so far found from a single site and belonging to the same biological population. The SH dental sample includes a total of 452 permanent and deciduous teeth, representing a minimum of 27 individuals. We present a study of the dental size variation in these hominids, based on the analysis of the mandibular permanent dentition: lateral incisors, n=29; canines, n=27; third premolars, n=30; fourth premolars, n=34; first molars, n=38; second molars, n=38. We have obtained the buccolingual diameter and the crown area (measured on occlusal photographs) of these teeth, and used the bootstrap method to assess the amount of variation in the SH sample compared with the variation of a modern human sample from the Museu Antropologico of the Universidade of Coimbra (Portugal). The SH hominids have, in general terms, a dental size variation higher than that of the modern human sample. The analysis is especially conclusive for the canines. Furthermore, we have estimated the degree of sexual dimorphism of the SH sample by obtaining male and female dental subsamples by means of sexing the large sample of SH mandibular specimens. We obtained the index of sexual dimorphism (ISD=male mean/female mean) and the values were compared with those obtained from the sexed modern human sample from Coimbra, and with data found in the literature concerning several recent human populations. In all tooth classes the ISD of the SH hominids was higher than that of modern humans, but the differences were generally modest, except for the canines, thus suggesting that canine size sexual dimorphism in Homo heidelbergensis was probably greater than that of modern humans. Since the approach of sexing fossil specimens has some obvious limitations, these results should be assessed with caution. Additional data from SH and other European Middle Pleistocene sites would be necessary to test

  6. New discoveries and interpretations of hominid fossils and artifacts from Vindija Cave, Croatia.

    Science.gov (United States)

    Ahern, James C M; Karavanić, Ivor; Paunović, Maja; Janković, Ivor; Smith, Fred H

    2004-01-01

    Beginning with excavations during the 1970s, Vindija Cave (Croatia) has yielded significant Middle and Upper Paleolithic fossil and archaeological finds. We report on seven recently identified hominid fossils, a newly associated partial hominid cranial vault from level G(3), nine possible bone retouchers, and a revised interpretation of the Mousterian artifact assemblage from the site. This new information reinforces our knowledge of the complex biocultural phenomena revealed in unit G and earlier deposits at Vindija. Six of the new hominid fossils derive from stratigraphic units G and I, while one lacks exact provenience. All specimens preserving diagnostic anatomy are from Neandertals. One of the postcranial remains, a radius fragment which exhibits Neandertal-like anatomy, comes from level G(1)and is congruent with the previously established association of Neandertals with an early Upper Paleolithic industry at the site. The partial cranial vault represents the most complete Neandertal from Vindija. The possible retouchers derive from unit G. Our analysis of these artifacts suggests that both percussion and pressure techniques may have been used by Neandertals in the final stage of tool production (retouching). This paper also presents a revision of the artifact analysis for late Mousterian level G(3). We separated raw materials into two main groups due to the differing ways that the materials fracture and the differing morphology of the debitage. The use of raw material in level G(3)is different from earlier Middle Paleolithic levels at Vindija. This indicates that the G(3)late Neandertals were making choices regarding source material somewhat more like the Upper Paleolithic people at the site. When interpreted within a larger regional framework, the Vindija archaeological and hominid fossil remains demonstrate a complex, mosaic pattern of biocultural change in the Late Pleistocene of south-central Europe.

  7. Relationship of squamosal suture to asterion in pongids (Pan): relevance to early hominid brain evolution.

    Science.gov (United States)

    Holloway, R L; Shapiro, J S

    1992-11-01

    Based on 244 measurements of the relationship of the squamosal suture to the landmark asterion in 49 chimpanzee skulls, it is shown that in the normal lateral view the squamosal suture is very rarely inferior to asterion. In hominid crania, the squamosal suture is always well superior to asterion. Even in Pan, that part of the squamosal suture most homologous with the remnant found on the Hadar AL 162-28 Australopithecus afarensis hominid cranial fragment is very rarely inferior to asterion. Such variability suggests that Falk's (Nature 313:45-47, 1985) orientation of the Hadar specimen is incorrect; she places asterion superior to the position of the squamosal suture if projected endocranially. The implication for the brain endocast is that, however the fragment is oriented, the posterior aspect of the intraparietal (IP) sulcus is in a very posterior position relative to any chimpanzee brain. The distance from the posterior aspect of IP to occipital pole is twice as great in chimpanzee brain casts than on the Hadar AL 162-28 endocast, even though the chimpanzee brain casts are smaller in overall size. This suggests that brain reorganization, at least as exemplified as a reduction in primary visual striate cortex (area 17 of Brodmann), occurred early in hominid evolution, prior to any major brain expansion.

  8. Mio-Pliocene glaciations of Central Patagonia: New evidence and tectonic implications Glaciaciones mio-pliocenas en Patagonia central: nueva evidencia e implicancias tectónicas

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    Yves Lagabrielle

    2010-07-01

    Full Text Available Patagonia is well known for spectacular oceurrences of a variety of glacial-derived landforms and deposits and for a long history of ancient glaciations. In this paper, we first review the diverse evidence that demonstrates the development of glacial-related sedimentary units within the Central Patagonian Cordillera since 7 Ma. Well preserved glacial landforms at the top surface of mesetas on both sides of the Lago General Carrera-Buenos Aires are described: the Meseta Guenguel to the north, and the volcanic Meseta del Lago Buenos Aires to the south. The latter meseta corresponds to a 3 Ma old, morphologically inverted paleo-piedmont, based on Ar/Ar dates of the uppermost lava flows. It shows evidence of glacier advances to the NE direction. Over a distance of 20 km, glacial landforms observed by remote sensing data and digital elevation model define glacial tongues that were fed by the Cordillera reliefs to the west. These lobes are now beheaded from their westward sources along a morpho-structural corridor that bounds the Meseta del Lago Buenos Aires to the west. These remnants can be correlated with the oldest glacial landforms recognized north of Lago General Carrera-Buenos Aires, on the Meseta Guenguel that form the Chipanque moraine system. From these features it is concluded that the glacial drainage network of Central Patagonia has been strongly modified following relief inversion in response to erosion processes and to tectonic causes. Changes occurred after 3 Ma, from a smooth piedmont surface covered by an extensive ice mantle ending with ampie glacial lobes, to the current series of deeply incised glacial valleys such as the Lago General Carrera-Buenos Aires depression. These new data bear important con-straints on the history and development of the first glaciations in southern South America.Patagonia es bien conocida por una espectacular geomorfología glacial y por una larga historia de antiguas glaciaciones. En este artículooprimero se describe la variada evidencia que demuestra el desarrolloo, desde hace 7 Ma, de unidades sedimentarias glacigénicas en la Cordillera Patagónica Central. Luego se describe una bien preservada geomorfología glacial en la cima de mesetas expuestas a ambos lados del lago General Carrera-Buenos Aires: en la Meseta Guenguel en el lado norte y en la meseta volcánica del lago Buenos Aires en el lado sur. Esta última corresponde a un paleo-piedemonte morfológicamente invertido de 3 Ma acorde a edades Ar/Ar de las lavas basálticas superiores. Exhibe evidencia del avance de glaciares hacia el NE. Observaciones hechas con sensores remotos y con modelos de elevación digital evidenciaron la presencia de formas glaciales a loolargo de una distancia de 20 km, las que fueron alimentadas desde los relieves cordilleranos ubicados al oeste. Estos lóbulos están ahora descabezados de su fuente ubicada al oeste a loolargo de un corredor morfoestructural que limita la Meseta del lago Buenos Aires por el oeste. Estos remanentes pueden ser correlacionados con las formas glaciales más antiguas reconocidas al norte del lago General Carrera-Buenos Aires en la Meseta Guenguel y que forman el sistema de morrenas Chipanque. Sobre la base de estos antecedentes se concluye que el sistema de drenaje de la Patagonia Central ha sido fuertemente modificado subsecuentemente a la inversion del relieve en respuesta a procesos erosivos y a causas tectónicas. Hubo cambios después de 3 Ma, desde una suave superficie de piedemonte cubierta por un extenso manto de hielooterminando con amplios lóbulos glaciales, hasta la actual serie de valles glaciales profundamente incididos tales como la depresión del lago General Carrera-Buenos Aires. Estos nuevos datos entregan importantes antecedentes a la historia y desarrolloode las primeras glaciaciones cenozoicas del sur de América del Sur.

  9. Influence of the Eastern California Shear Zone on deposition of the Mio-Pliocene Bouse Formation: Insights from the Cibola area, Arizona

    Science.gov (United States)

    Dorsey, Rebecca J.; O'Connell, Brennan; Homan, Mindy B.; Bennett, Scott E. K.

    2017-01-01

    The Eastern California Shear Zone (ECSZ) is a wide zone of late Cenozoic strike-slip faults and related diffuse deformation that currently accommodates ~20–25% of relative Pacific–North America plate motion in the lower Colorado River region (Fig. 1A; Dokka and Travis, 1990; Miller et al., 2001; Guest et al., 2007; Mahan et al., 2009). The ECSZ is kinematically linked southward to dextral faults in the northern Gulf of California (Bennett et al., 2016a), and it may have initiated ca. 8 Ma when major strike-slip faults developed in the northern Gulf and Salton Trough region (Bennett et al., 2016b; Darin et al., 2016; Woodburne, 2017). Thus deformation related to the ECSZ occurred in the lower Colorado River region during deposition of the Bouse Formation, which is commonly bracketed between 6.0 and 4.8 Ma (House et al., 2008; Sarna-Wojcicki et al., 2011; Spencer et al., 2013) and may be as old as 6–7 Ma in the south (McDougall and Miranda Martínez, 2014, 2016). Post-4.5 Ma broad sagging is recognized along the lower Colorado River (Howard et al., 2015), but the possibility that faults of the ECSZ influenced local to regional subsidence patterns during deposition of the Bouse Formation has received little attention to date (e.g., Homan, 2014; O’Connell et al., 2016). The Bouse Formation is a widespread sequence of late Miocene to early Pliocene deposits exposed discontinuously along the lower Colorado River corridor (Fig. 1A). In the southern Blythe basin it consists of three regionally correlative members: (1) Basal Carbonate, consisting of supratidal and intertidal mud-flat marls, intertidal and shallow subtidal bioclastic grainstone and conglomerate, and subtidal marl; (2) Siliciclastic member, consisting of Colorado River-derived green claystone, red mudstone and siltstone, and cross-bedded river channel sandstone; and (3) Upper Bioclastic member fossiliferous sandy calcarenite, coarse pebbly grainstone, and calcareous-matrix conglomerate (Homan, 2014; Dorsey et al., 2016; O’Connell et al., 2016, 2017). The southern Bouse Formation has been interpreted as recording deposition in either a lake (Spencer and Patchett, 1997; Spencer et al., 2008, 2013; Bright et al., 2016) or shallow marine setting (Buising, 1990; McDougall, 2008; McDougall and Miranda Martínez, 2014; O’Connell et al., 2017).In this paper we summarize key results from five field seasons of detailed stratigraphic analysis south of Cibola, Ariz. ( . 1). The data reveal systematic stratal thinning and thickening, pinch-outs, and wedging patterns in the Bouse Formation that we conclude were produced by syn-depositional tilting in response to growth of normal faults near the eastern margin of the basin. Similar stratal patterns in other nearby areas suggest widespread structural controls on deposition of the Bouse Formation. A palinspastic reconstruction of the lower Colorado River region at 5 Ma, modified from Bennett et al. (2016), provides insight to regional fault geometries in the ECSZ that may have controlled syn-depositional tilting and subsidence in Bouse depocenters shortly prior to and during initiation of the Colorado River.

  10. Comparative Taphonomy, Taphofacies, and Bonebeds of the Mio-Pliocene Purisima Formation, Central California: Strong Physical Control on Marine Vertebrate Preservation in Shallow Marine Settings

    Science.gov (United States)

    Boessenecker, Robert W.; Perry, Frank A.; Schmitt, James G.

    2014-01-01

    Background Taphonomic study of marine vertebrate remains has traditionally focused on single skeletons, lagerstätten, or bonebed genesis with few attempts to document environmental gradients in preservation. As such, establishment of a concrete taphonomic model for shallow marine vertebrate assemblages is lacking. The Neogene Purisima Formation of Northern California, a richly fossiliferous unit recording nearshore to offshore depositional settings, offers a unique opportunity to examine preservational trends across these settings. Methodology/Principal Findings Lithofacies analysis was conducted to place vertebrate fossils within a hydrodynamic and depositional environmental context. Taphonomic data including abrasion, fragmentation, phosphatization, articulation, polish, and biogenic bone modification were recorded for over 1000 vertebrate fossils of sharks, bony fish, birds, pinnipeds, odontocetes, mysticetes, sirenians, and land mammals. These data were used to compare both preservation of multiple taxa within a single lithofacies and preservation of individual taxa across lithofacies to document environmental gradients in preservation. Differential preservation between taxa indicates strong preservational bias within the Purisima Formation. Varying levels of abrasion, fragmentation, phosphatization, and articulation are strongly correlative with physical processes of sediment transport and sedimentation rate. Preservational characteristics were used to delineate four taphofacies corresponding to inner, middle, and outer shelf settings, and bonebeds. Application of sequence stratigraphic methods shows that bonebeds mark major stratigraphic discontinuities, while packages of rock between discontinuities consistently exhibit onshore-offshore changes in taphofacies. Conclusions/Significance Changes in vertebrate preservation and bonebed character between lithofacies closely correspond to onshore-offshore changes in depositional setting, indicating that the dominant control of preservation is exerted by physical processes. The strong physical control on marine vertebrate preservation and preservational bias within the Purisima Formation has implications for paleoecologic and paleobiologic studies of marine vertebrates. Evidence of preservational bias among marine vertebrates suggests that careful consideration of taphonomic overprint must be undertaken before meaningful paleoecologic interpretations of shallow marine vertebrates is attempted. PMID:24626134

  11. The Quequén Salado river basin: Geology and biochronostratigraphy of the Mio-Pliocene boundary in the southern Pampean plain, Argentina

    Science.gov (United States)

    Beilinson, E.; Gasparini, G. M.; Tomassini, R. L.; Zárate, M. A.; Deschamps, C. M.; Barendregt, R. W.; Rabassa, J.

    2017-07-01

    The Quequén Salado river basin has been the focus of several contributions since the first decades of the XX century, namely dealing with the general geological features of the deposits and with the vertebrate remains. In this paper, the Neogene geological history documented by the Quequén Salado river exposures is reconstructed by means of stratigraphic, sedimentological and paleomagnetic studies along with the paleontological analysis of vertebrate remains. The study area is a crucial setting not only to better understand the evolution of the southern Pampas basin during the late Miocene-early Pliocene interval, but also to test the validity of the biochronologic and biostratigraphic schemes, especially the "Irenense". A geological model for the Quequén Salado river valley is proposed: a case of downcutting and headward erosion that contributes with a coherent interpretation to explain the spatial distribution of facies and fossil taxa: the younger in the distal sector of the Quequén Salado middle basin and the older in the lower basin. The sedimentary record is believed to represent the distal reaches of a distributary fluvial system that drained from the Ventania ranges. The stratigraphic section of Paso del Indio Rico results a key stratigraphic site to fully understand the stratigraphic nature of the boundary between the Miocene and the Pliocene (the Huayquerian and Montehermosan stages/ages). In this sense, two stratigraphically superposed range zones have been recognized in the area: Xenodontomys ellipticus Range Zone (latest Miocene-early Pliocene; late Huayquerian), and Eumysops laeviplicatus Range Zone (early Pliocene; Montehermosan). Taking into account the available geological and paleontological evidences, the "Irenense" would not represent a valid biostratigraphic unit, since, according to the geological model here proposed, it would be represented by elements of the Xenodontomys ellipticus Range Zone in the lower QS basin and by elements of the Eumysops laeviplicatus Range Zone in the middle QS basin.

  12. Comparative taphonomy, taphofacies, and bonebeds of the Mio-Pliocene Purisima Formation, central California: strong physical control on marine vertebrate preservation in shallow marine settings.

    Directory of Open Access Journals (Sweden)

    Robert W Boessenecker

    Full Text Available Taphonomic study of marine vertebrate remains has traditionally focused on single skeletons, lagerstätten, or bonebed genesis with few attempts to document environmental gradients in preservation. As such, establishment of a concrete taphonomic model for shallow marine vertebrate assemblages is lacking. The Neogene Purisima Formation of Northern California, a richly fossiliferous unit recording nearshore to offshore depositional settings, offers a unique opportunity to examine preservational trends across these settings.Lithofacies analysis was conducted to place vertebrate fossils within a hydrodynamic and depositional environmental context. Taphonomic data including abrasion, fragmentation, phosphatization, articulation, polish, and biogenic bone modification were recorded for over 1000 vertebrate fossils of sharks, bony fish, birds, pinnipeds, odontocetes, mysticetes, sirenians, and land mammals. These data were used to compare both preservation of multiple taxa within a single lithofacies and preservation of individual taxa across lithofacies to document environmental gradients in preservation. Differential preservation between taxa indicates strong preservational bias within the Purisima Formation. Varying levels of abrasion, fragmentation, phosphatization, and articulation are strongly correlative with physical processes of sediment transport and sedimentation rate. Preservational characteristics were used to delineate four taphofacies corresponding to inner, middle, and outer shelf settings, and bonebeds. Application of sequence stratigraphic methods shows that bonebeds mark major stratigraphic discontinuities, while packages of rock between discontinuities consistently exhibit onshore-offshore changes in taphofacies.Changes in vertebrate preservation and bonebed character between lithofacies closely correspond to onshore-offshore changes in depositional setting, indicating that the dominant control of preservation is exerted by physical processes. The strong physical control on marine vertebrate preservation and preservational bias within the Purisima Formation has implications for paleoecologic and paleobiologic studies of marine vertebrates. Evidence of preservational bias among marine vertebrates suggests that careful consideration of taphonomic overprint must be undertaken before meaningful paleoecologic interpretations of shallow marine vertebrates is attempted.

  13. Variations of the Indian summer monsoon over the Mio-Pliocene recorded in the Bengal Fan (IODP Exp354): implications for the evolution of the terrestrial biosphere.

    Science.gov (United States)

    Galy, Valier; Feakins, Sarah; Karkabi, Elias; Ponton, Camilo; Galy, Albert; France-Lanord, Christian

    2017-04-01

    A pressing challenge in climate research is understanding the temporal evolution of the Indian monsoon system; its response to global and regional climatic controls (including warming); as well as implications in terms of vegetation (C4 expansion), erosion of the Himalaya and carbon sequestration in the Bengal Fan. Studies on climate dynamics have recently offered new insights into the mechanistic controls on the monsoon: the tectonic boundary of the Himalaya is implicated as the major control on Indian summer monsoon dynamics today. Since this region has been uplifted since at least the late Oligocene, it is possible to test the response of monsoon precipitation to global and regional climate change, and also understand feedbacks on the climate system via carbon sequestration in the Bengal Fan. The evidence for monsoon intensity changes across the Miocene and Pliocene is currently incomplete given temporal uncertainty and diagenesis in terrestrial records; biases in the records reconstructed from the distal fan; and conflicting evidence from wind speed and aridity metrics for a stronger or weaker monsoon. Our alternative approach is therefore to study the basin-wide hydrological changes recorded in a multi-proxy, multi-site study of the marine sediments of the Bengal Fan recovered during IODP expedition 354. In turbiditic sediments of Himalayan origin, the late Miocene C4 expansion was found in all three long records recovered during expedition 354 (i.e. at sites U1451, U1450 and U1455, from East to West) based on stable carbon isotope composition of terrestrial leaf-wax compounds. Cores from sites U1455 (a reoccupation of DSDP Leg 22 Site 218) provide the highest resolution record of the C4 transition, which appears to occur abruptly within a relatively continuous series of turbiditic sequences. Bio- and magneto-stratigraphic dating of these records by members of Expedition 354 science party is underway and will provide the best stratigraphic constraint of the C4 expansion in the Himalayan system. Hemipelagic sediments generally carry 13C enriched signatures indicative of C4-dominated source areas, and based on a combination of the wind field climatology and the wetness and ecosystems of source regions today, we suggest that these would likely represent wind transport, likely from peninsular India. Interestingly we found hemipelagic horizons carrying this enriched 13C character prior to the C4 expansion recorded in turbiditic sediments, likely revealing an earlier C4 colonization of peninsular India. Based on our preliminary data we thus propose that C4 plants colonized peninsular India around 9-10 Ma. The hydrogen isotopic composition of the same leaf-wax compounds reveals a surprisingly small (on the order of 10 ‰) isotopic shift associated with the late Miocene C4 expansion. In contrast, the hydrogen isotope composition shift observed across the last deglaciation is far greater (ca. 40‰; Hein et al., in prep.). Cores from site U1451, provide a low resolution record across at least the last 26 Myr and appear to indicate a long term hydrological change from ca. 11Ma to ca. 7Ma, as inferred from progressive D enrichment in the biomarker records. These compound specific hydrogen isotope data will be discussed in the context of changing erosion patterns and attendant variations in the strength of the Indian summer monsoon as well as with respect to the mechanisms that led to the C4 expansion.

  14. Pattern of dental development in Hominid XVIII from the Middle Pleistocene Atapuerca-Sima de los Huesos site (Spain).

    Science.gov (United States)

    Bermudez De Castro, J M; Rosas, A

    2001-04-01

    . We describe the pattern of dental development of Hominid XVIII from the Middle Pleistocene Sima de los Huesos (SH) site of the Sierra de Atapuerca (Burgos, Spain). As expected, this pattern is similar to that of modern humans. A delay of development of the lower and upper canines was observed. In contrast, the relative advanced development of the lower second molars and, especially, the upper and lower third molars is noteworthy. This latter feature seems to be common in Pleistocene hominids, and suggests that the pattern of dental development evolved in the genus Homo during the Pleistocene. In European Middle Pleistocene hominids, this pattern probably was facilitated by the extra space available in the mandible and maxilla for developing teeth. Copyright 2001 Wiley-Liss, Inc.

  15. Taphonomy of the fossil hominid bones from the Acheulean site of Castel di Guido near Rome, Italy.

    Science.gov (United States)

    Mariani-Costantini, R; Ottini, L; Caramiello, S; Palmirotta, R; Mallegni, F; Rossi, A; Frati, L; Capasso, L

    2001-09-01

    Castel di Guido near Rome is one of the few open air Middle Pleistocene European sites that has yielded hominid skeletal remains associated with fossil fauna and Acheulean implements. The fossil hominid bones include two femoral shafts, respectively designated Castel di Guido-1 (CdG-1) and CdG-2, an occipital fragment (CdG-3), a right maxilla lacking teeth (CdG-4), a portion of right parietal (CdG-5), a right temporal (CdG-6), and a fragment of left parietal vault (CdG-7). CdG-1 through CdG-4 were collected in 1979-1982 on the surface, together with fossil fauna, where ploughing incised fossiliferous tuffaceous sands. Excavations conducted in the same area from 1980 to 1990 led to the discovery of CdG-5, CdG-6 and CdG-7 within the tuffaceous sands, which were shown to overlay a bone-bearing paleosurface, with abundant evidence of hominid activities. The Castel di Guido hominid assemblage poses intriguing taphonomic questions. The analysis of the physical evidence offered by the bone surfaces, reported in the present study, indicates that the hominid skeletal remains were heavily fragmented before fossilization and exposed to carnivores and rodents, as well as to trampling and/or friction in abrasive sediment. Although definitive conclusions cannot be reached on the basis of the available evidence, it is possible that clusters of incisions localized on specific regions of the Castel di Guido fossil hominid bones might reflect deliberate human manipulations. Copyright 2001 Academic Press.

  16. A new horned crocodile from the Plio-Pleistocene hominid sites at Olduvai Gorge, Tanzania.

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    Christopher A Brochu

    Full Text Available BACKGROUND: The fossil record reveals surprising crocodile diversity in the Neogene of Africa, but relationships with their living relatives and the biogeographic origins of the modern African crocodylian fauna are poorly understood. A Plio-Pleistocene crocodile from Olduvai Gorge, Tanzania, represents a new extinct species and shows that high crocodylian diversity in Africa persisted after the Miocene. It had prominent triangular "horns" over the ears and a relatively deep snout, these resemble those of the recently extinct Malagasy crocodile Voay robustus, but the new species lacks features found among osteolaemines and shares derived similarities with living species of Crocodylus. METHODOLOGY/PRINCIPAL FINDINGS: The holotype consists of a partial skull and skeleton and was collected on the surface between two tuffs dated to approximately 1.84 million years (Ma, in the same interval near the type localities for the hominids Homo habilis and Australopithecus boisei. It was compared with previously-collected material from Olduvai Gorge referable to the same species. Phylogenetic analysis places the new form within or adjacent to crown Crocodylus. CONCLUSIONS/SIGNIFICANCE: The new crocodile species was the largest predator encountered by our ancestors at Olduvai Gorge, as indicated by hominid specimens preserving crocodile bite marks from these sites. The new species also reinforces the emerging view of high crocodylian diversity throughout the Neogene, and it represents one of the few extinct species referable to crown genus Crocodylus.

  17. A Homo habilis maxilla and other newly-discovered hominid fossils from Olduvai Gorge, Tanzania.

    Science.gov (United States)

    Clarke, R J

    2012-08-01

    In 1995, a 1.8 million year old hominid maxilla with complete dentition (OH 65) was excavated from Bed I in the western part of Olduvai Gorge. The molar crowns are small relative to the long flaring roots, and the root of the canine is very long and straight. The broad maxilla with wide U-shaped palate and the form of the tooth roots closely match those of KNM-ER 1470 which, in its parietal size and morphology, matches the type specimen of Homo habilis, OH 7. Thus, OH 65 and KNM-ER 1470 group with OH 7 as representatives of H. habilis while some other Olduvai specimens, such as OH 13 and OH 24, have more in common in terms of morphology and brain size with Australopithecus africanus. Between 1995 and 2007, the OLAPP team has recovered teeth of eight other hominid individuals from various parts of Olduvai Gorge. These have been identified as belonging to H. habilis, Paranthropus boisei, and Australopithecus cf. africanus. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Comparative morphometric analysis of the proximal femur of African hominids and felids

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    Andrew Gallagher

    2015-09-01

    Full Text Available Size and shape of the mammalian proximal femur and taxon-specific distinctions in the relative proportions of the proximal articulation, the femoral neck and the proximal femoral diaphysis, are critical determinants in its adaptation to differential biomechanical stresses and observed locomotor habitus in different taxa. The morphometrics of the proximal femur are considered equally critical in the assessment of locomotor habitus of extinct fossil mammals, particularly extinct Miocene anthropoids and Plio-Pleistocene hominins. Analyses of size and shape of k=10 dimensions of the proximal femur were undertaken for a large sample series of two extant mammal families the Felidae and Hominidae using conventional multivariate statistical procedures, commonly used size-correction methods, and post-hoc tests of significance. While significant differences in form do exist, there are equally striking convergences in the functional morphology of extant hominid and felid taxa. Multivariate and bivariate allometric analyses confirm that the proximal femur of these two mammalian families share a common underlying structure manifest in a shared first common principal component. Nevertheless, while considerable convergences in general form of the proximal femur of African hominids and large-bodied felids are apparent, there exist equally discreet distinctions which are consistent with the differential structural demands imposed by their distinct locomotor and behavioural habitus.

  19. Experimental determinations of carcass processing by Plio-Pleistocene hominids and carnivores at FLK 22 (Zinjanthropus). Olduvai Gorge, Tanzania.

    Science.gov (United States)

    Capaldo, S D

    1997-11-01

    Published and unpublished skeletal and surface mark data from the large, well-preserved, bovid dominated FLK 22 (Zinjanthropus) archaeofauna are analyzed using data derived from four different experimental control samples. The control samples are realistic because they are based on natural history and paleoecological data collected from FLK 22, and other Olduvai Gorge assemblages; they are precise because independent experimental studies following the same methods have generated the same results; and they restore generality to the study of site formation because each one models a different hominid and/or carnivore scenario of site formation. Comparability between FLK 22 and the control samples is established by excluding specimens from the former which do not meet identification and reporting standards derived from the latter. As in two previous studies, a comprehensive analysis of tooth marks and tool marks on long bone specimens from FLK 22 indicates that they were processed in three stages. In stage one, carnivores defleshed long bones, as inferred from the high percentage of tooth marks on midshaft fragments. In stage two, hominids processed intact long bones for marrow, as inferred from percussion mark percentages. Cut marks suggest that long bones retained flesh, but the amount, as yet, cannot be determined using cut mark percentages. In stage three, carnivores processed long bone epiphyses for grease, as inferred from the under-representation of long bone epiphyses and the high percentage of tooth marks on near-epiphyses and surviving epiphyses. The lack of comprehensive skeletal and surface mark data on cranial, axial, compact, and other specimens currently limits the application of experimental results. However, the available data suggest that the condition and representation of these items in the FLK 22 assemblage are also consistent with a carnivore to hominid to carnivore sequence of site formation. The variety of elements present, and their extensive

  20. Ages of tuff beds at East African early hominid sites and sediments in the Gulf of Aden

    Science.gov (United States)

    Sarna-Wojcicki, A. M.; Meyer, C.E.; Roth, P.H.; Brown, F.H.

    1985-01-01

    The early hominids of East Africa were dated by determining the ages of tuff beds at the sites. Despite much research using palaeomagnetic and K/Ar-dating techniques, some of those ages are still controversial 1,2. To obtain independent age estimates for these tephra layers, we have examined cores from DSDP Sites 231 and 232 in the Gulf of Aden (Fig. 1a) which consist mainly of calcareous nannofossil ooze, but also contain rare tephra horizons3 dated by interpolation from the established nannofossil stratigraphy (Fig. 1b). Chemical analysis confirms that the identity and sequence of these horizons is the same as that at the East African sites. We conclude that the age of the Tulu Bor Tuff is <3.4 Myr and hence that the Hadar hominid specimens are also

  1. On the age of the hominid fossils at the Sima de los Huesos, Sierra de Atapuerca, Spain: paleomagnetic evidence.

    Science.gov (United States)

    Parés, J M; Pérez-González, A; Weil, A B; Arsuaga, J L

    2000-04-01

    We report new paleomagnetic data for the Middle Pleistocene hominid-bearing strata in the Sima de los Huesos, North Spain. Sediments (brown muds with human and bear fossils and the underlying sterile clayey and sandy unit) preserve both normal and reversed magnetic components. The sterile unit has exclusively reversed magnetization, dating back to the Matuyama Chron, and thus is Lower Pleistocene in age. The overlying fossiliferous muds have a dominant normal magnetization that overprints a partially resolved reversed magnetization. These data are compatible with one of the reversal events that occurred during the Brunhes Chron. Combined with the existing U-series dates and evidence from the macro- and microfauna, these paleomagnetic results suggest an age of the hominid fossils between 325 to 205 ka, whereas the underlying sand and silts are older than 780 ka. Copyright 2000 Wiley-Liss, Inc.

  2. Analysis of the dental morphology of Plio-Pleistocene hominids. IV. Mandibular postcanine root morphology.

    Science.gov (United States)

    Wood, B A; Abbott, S A; Uytterschaut, H

    1988-02-01

    The subocclusal morphology of 168 permanent mandibular premolars (N = 77) and molars (N = 91) of Plio-Pleistocene hominids has been investigated. The taxonomic allocation of the teeth, which represent at least 46 individuals, was based on nondental evidence. Specimens were allocated to one of two major taxonomic categories, (EAFROB or EAFHOM), East African Homo erectus (EAFHER), or their taxonomic affinity was regarded as 'unknown' (N = 17). Information about the root system was derived from radiography and direct observation. Morphometric data were in the form of nine linear and two angular measurements based on eighteen reference points. Root form was also assessed using a scheme which recognised four classes of root morphology. Data were compared using both univariate and multivariate techniques, including Principal Component and Canonical Variate analysis. Posterior probabilities derived from the latter were used (in a two-taxon design model) to assess the affinities of the 'unknown' specimens. The variation in hominid mandibular premolar root form was interpreted as two morphoclines, based on the presumed primitive condition of the P3 (with mesiobuccal and distal roots, 2R: MB and D) and P4 (with mesial and distal root, 2R: M and D) root systems. One trend apparently leads towards root reduction (i.e. P3 = 1 R; P4 = 1 R), and the other to root elaboration (i.e. P3 and P4 = 2R: M and D). The extreme form of the latter is the 'molarisation' of the premolar roots seen in EAFROB. Despite major differences in root form there was relatively little taxonomic variation in root metrics, except for a more robust distal root system in EAFROB. Molar root form showed little interspecific variation except for M2 in which the roots in EAFROB were larger and more robust, with differences in root height being greater for the distal than for the mesial roots. Root form and metrics enable four of the 'unknown' specimens (KMN-ER 819, 1482, 1483 and 1801) to be tentatively

  3. Pliocene and pleistocene hominid-bearing sites from west of lake turkana, kenya.

    Science.gov (United States)

    Harris, J M; Brown, F H; Leakey, M G; Walker, A C; Leakey, R E

    1988-01-01

    Pliocene and Pleistocene fossil localities near the western shoreline of Lake Turkana, ranging in age between 1 million and 3.5 million years in age, have produced important new hominid specimens including most of a Homo erectus skeleton and a relatively complete early robust australopithecine cranium. The lacustrine, fluviatile, and terrestrial strata are designated the Nachukui Formation, which is subdivided into eight members. The distribution of sedimentary facies within the Nachukui Formation suggests that, as today, the Labur and Murua Rith ranges formed the western margin of the basin and were drained by eastward-flowing rivers that fed into the forerunner of the present lake or a major river system. There is also stratigraphic evidence for tectonic movement during the deposition of these sediments. Twenty-three of the tuffs observed in the succession occur also in the Koobi Fora Formation east of the lake and in the Shungura Formation of the lower Omo Valley and permit precise correlation among these three localities. Fortyseven fossiliferous sites from West Turkana have yielded more than 1000 specimens of 93 mammalian species. The mammalian fossils represent nine sequential assemblages that augment information about faunal and environmental change from elsewhere in the basin.

  4. Further analysis of mandibular molar crown and cusp areas in Pliocene and early Pleistocene hominids.

    Science.gov (United States)

    Suwa, G; Wood, B A; White, T D

    1994-04-01

    Crown and cusp areas of mandibular molars were measured and analyzed on a sample of 249 specimens attributed to Australopithecus afarensis, A. africanus, A. (Paranthropus) robustus, A. (P.) boisei, and early Homo. In addition to intertaxon comparisons, we compared data that had been collected independently by two of the authors using methods that differ slightly in technique of measurement. Interobserver differences were evaluated by the t-test of paired comparisons, method error statistic, percent differences, and principal component analysis. Results suggest that between-technique error of measurement of overall crown area is small. Error estimates for individual cusp area measurements were of larger relative magnitude. However, these were not sufficient to detract from the conclusions derived from comparative analyses. Our results are in general agreement with previous assessments of early hominid dental size. Crown areas of A. africanus, however, exhibit a mosaic pattern, with M1 similar in size to that of A. afarensis and early Homo, and M2 and M3 similar in size to that of A. robustus. Intertaxon comparisons of relative cusp area were undertaken by univariate statistics and principal component analysis. These analyses revealed that while A. (P.) robustus and A. (P.) boisei both possess mandibular molars with cusp proportions significantly different from the 'non-robust' taxa, these differences are substantially greater in A. (P.) boisei.

  5. Meat-eating by early hominids at the FLK 22 Zinjanthropus site, Olduvai Gorge (Tanzania): an experimental approach using cut-mark data.

    Science.gov (United States)

    Domínguez-Rodrigo, M

    1997-12-01

    The meat-eating behavior of Plio-Pleistocene hominids, responsible for the bone accumulations at the earliest archaeological sites, is still a hotly-debated issue in paleoanthropology. In particular, meat-eating and bone marrow consumption are often presented as either complementary or opposing strategies of carcass exploitation. The presence of cut marks on fossil archeofauna is a potential source of information that has not been consistently used as evidence of carcass consumption by hominids. Some authors interpret cut marks as the result of hominids manipulating meat-bearing bones, while others argue that they can also be the result of hominids extracting marginal scraps of carcass flesh that have survived carnivores' initial consumption. In this study, a referential framework concerning the interpretation of cut marks is presented, based on a set of experiments conducted by the author. It is suggested, according to these experiments and data drawn from the FLK "Zinj" site, that hominids processed meat-bearing bones (on which flesh was abundant) rather than defleshed carcasses from felid kills.

  6. Analysis of the dental morphology of Plio-pleistocene hominids. I. Mandibular molars: crown area measurements and morphological traits.

    Science.gov (United States)

    Wood, B A; Abbott, S A

    1983-01-01

    This study has used accurate measurements of crown area and precise assessments of the morphological traits of mandibular molars in an attempt to define the metrical and morphological characteristics of early hominid taxa. A total of 196 Plio-Pleistocene hominid molars were either allocated to one of six informal taxonomic groups or considered as individual cases. Accurate measurements of crown base area made from occlusal photographs have enabled us to estimate the effects of interproximal wear on crown areas. The average correction factor over the three molar types is around 2-4% with a maximum of 6%. The patterns of distribution of extra cusps show interesting differences between taxa. None of the M-1S in the two groups of 'gracile' hominids from East and South Africa bears a C6, but it is common in the two 'robust' taxa. The distribution of a C7 is the reverse of this, it being rare in the robust' taxa, and more common in the 'gracile' groups. There is thus no simple relationship between cusp number and tooth size. Our observations on the protostylid suggest that though it is more common in the 'robust' australopithecines than the 'graciles', when it does occur it is more strongly expressed in the 'gracile' group. The combination of simple metrical data, and the assessment of morphological traits, can help in the classification of enigmatic or incomplete specimens. Some isolated teeth from the collection at Koobi Fora can confidently be assigned to Australopithecus boisei, and useful guides have been provided for taxonomic assessment of the skull KNM-ER 1805, and the mandibles KNM-ER 1506 and 1820.

  7. Geometric morphometric analysis of allometric variation in the mandibular morphology of the hominids of Atapuerca, Sima de los Huesos site.

    Science.gov (United States)

    Rosas, Antonio; Bastir, Markus

    2004-06-01

    Allometry is an important factor of morphological integration that contributes to the organization of the phenotype and its variation. Variation in the allometric shape of the mandible is particularly important in hominid evolution because the mandible carries important taxonomic traits. Some of these traits are known to covary with size, particularly the retromolar space, symphyseal curvature, and position of the mental foramen. The mandible is a well studied system in the context of the evolutionary development of complex morphological structures because it is composed of different developmental units that are integrated within a single bone. In the present study, we investigated the allometric variation of two important developmental units that are separated by the inferior nerve (a branch of CN V3). We tested the null hypothesis that there would be no difference in allometric variation between the two components. Procrustes-based geometric morphometrics of 20 two-dimensional (2D) landmarks were analyzed by multivariate regressions of shape on size in samples from 121 humans, 48 chimpanzees, and 50 gorillas (all recent specimens), eight fossil hominids from Atapuerca, Sima de los Huesos (AT-SH), and 17 Neandertals. The findings show that in all of the examined species, there was significantly greater allometric variation in the supra-nerve unit than in the infra-nerve unit. The formation of the retromolar space exhibited an allometric relationship with the supra-nerve unit in all of the species studied. The formation of the chin-like morphology is an "apodynamic" feature of the infra-nerve unit in the AT-SH hominids. The results of this study support the hypothesis that allometry contributes to the organization of variation in complex morphological structures. Copyright 2004 Wiley-Liss, Inc.

  8. Taxonomic attribution of the Olduvai hominid 7 manual remains and the functional interpretation of hand morphology in robust australopithecines.

    Science.gov (United States)

    Moyà-Solà, Salvador; Kohler, Meike; Alba, David M; Almécija, Sergio

    2008-01-01

    In this paper, we test the currently accepted taxonomic hypothesis that the hand of the Homo habilis holotype Olduvai hominid 7 (OH7) from Olduvai Gorge can be unambiguously assigned to Homo. Morphometric and morphological comparison with humans and australopithecines (Australopithecus and Paranthropus) indicate that the OH7 hand most likely belongs to P. boisei. The morphological adaptations of Paranthropus are thus further evaluated in the light of the alternative taxonomic hypothesis for OH7. Functional analyses suggest that morphological features related to human-like precision grasping, previously considered diagnostic of toolmaking by some, may be alternatively attributed to specialized manual feeding techniques in robust australopithecines. Copyright 2008 S. Karger AG, Basel.

  9. A climate and environmental context for hominid evolution: Preliminary biomarker and compound specific isotope data from Lake Magadi, Kenya

    Science.gov (United States)

    Werne, J. P.; Ferland, T.; Cohen, A. S.; Lowenstein, T. K.; Deocampo, D.; Renaut, R.; Bernhart, O. R.

    2016-12-01

    The Hominid Sites and Paleolakes Drilling Project (HSPDP) seeks to understand the paleoclimatic and paleoenvironmental context of human evolution and development by analysis of paleolacustrine cores taken near key hominin fossil and artifact localities in Kenya and Ethiopia. Here, we present biomarker and compound specific isotope data from a 200 m drill core from Lake Magadi, Kenya. Located 20 km from the Koora Plain in the southern Kenya Rift, and adjacent to the Olorgesailie basin, Lake Magadi is in one of the richest Early-Late Pleistocene archaeological localities in Africa, a region that has been key in debates about the relationship between climate and evolution. Preliminary biomarker work has shown promising abundances of leaf waxes, whose isotopic compositions of hydrogen and carbon are commonly used as proxies for paleoprecipitation and watershed vegetation composition, respectively. A complementary record of glycerol dialkyl glycerol tetraethers (GDGTs), which can serve as a proxy for temperature, soil input, and/or pH, will be presented alongside the leaf wax data to enhance the paleoenvironmental reconstruction of Lake Magadi. Present-day Lake Magadi is a saline pan, a descendant of a series of paleolakes that have occupied its drainage basin for approximately one million years. Hominid evolution milestones such as the mastering of fire as a tool, rapid encephalization, and the emergence of Homo sapiens all are thought to have occurred in the time frame encompassed by our record.

  10. The Great Ape Project: legislating for the control of the use of non-human hominids in research, testing and teaching--Animal Welfare Act 1999 (New Zealand).

    Science.gov (United States)

    Wells, Neil

    2004-06-01

    The Animal Welfare Act 1999 (New Zealand), which commenced on January 1 2000, provides that the use of non-human hominids in research, testing or teaching is not permitted unless the Director-General of Agriculture approves the use, and then, only if the use is in the interests of the non-human hominid itself or its species. The Animal Welfare Act 1999 originated with two parliamentary bills. The first, a private member's bill in the name of Pete Hodgson MP, was tabled in 1997, and the second, a Government measure, was tabled a year later. Neither bill made any reference to non-human hominids. The Great Ape Project made submissions that non-human hominids be afforded similar rights to humans, i.e. not to be deprived of life, not to be subjected to torture or cruel treatment and not to be subjected to medical or scientific experimentation. Proponents and opponents of the measure argued for and against the tenet of introducing "rights" issues into what was essentially "welfare" legislation. These arguments are analysed, and the legislative process that enabled this modification is examined.

  11. Late Mio-Pliocene chemical weathering of the Yulong porphyry Cu deposit in the eastern Tibetan Plateau constrained by goethite (U-Th)/He dating: Implication for Asian summer monsoon

    Science.gov (United States)

    Deng, Xiao-Dong; Li, Jian-Wei; Shuster, David L.

    2017-08-01

    Chemical weathering has provided a potentially important feedback between tectonic forcing and climate evolution of the Asian continent, although precise constraints on the timing and history of weathering are only variably documented. Here, we use goethite (U-Th)/He and 4He/3He geochronology to constrain the timing and rates of chemical weathering at the Yulong porphyry Cu deposit on the eastern Tibetan Plateau. Goethite grains have (U-Th)/He ages ranging from 6.73 ± 0.51 to 0.53 ± 0.04 Ma that correlate with independent paleoclimatic proxies inferred from supergene Mn-oxides and loess deposits under variable tectonic regimes and vegetation zones over the southeastern Asia. This correlation indicates that regional climatic conditions, especially monsoonal precipitation, controlled chemical weathering and goethite precipitation in a vast area of southeastern Asia. The goethite ages suggest that the Asian summer monsoon was relatively strong from 7 to 4.6 Ma, but weakened between 4.6 and 4 Ma, and then significantly intensified from 4 to 2 Ma. The precipitation ages of goethites collected along a 100-m-thick weathering profile decrease with depth, and indicate a downward propagation of the weathering front at rates of table, which was possibly related to local surface uplift or reorganization of the river systems in southeastern Tibet during this period.

  12. The Sima de los Huesos hominids date to beyond U/Th equilibrium (>350 kyr) and perhaps to 400-500 kyr: New radiometric dates

    Science.gov (United States)

    Bischoff, J.L.; Shamp, D.D.; Aramburu, Arantza; Arsuaga, J.L.; Carbonell, E.; Bermudez de Castro, Jose Maria

    2003-01-01

    The Sima de los Huesos site of the Atapuerca complex near Burgos, Spain contains the skeletal remains of at least 28 individuals in a mud breccia underlying an accumulation of the Middle Pleistocene cave bear (U. deningeri). Earlier dating estimates of 200 to 320 kyr were based on U-series and ESR methods applied to bones, made inaccurate by unquantifiable uranium cycling. We report here on a new discovery within the Sima de los Huesos of human bones stratigraphically underlying an in situ speleothem. U-series analyses of the speleothem shows the lower part to be at isotopic U/Th equilibrium, translating to a firm lower limit of 350 kyr for the SH hominids. Finite dates on the upper part suggest a speleothem growth rate of c. 1 cm/32 kyr. This rate, along with paleontological constraints, place the likely age of the hominids in the interval of 400 to 600 kyr. ?? 2002 Elsevier Science Ltd. All rights reserved.

  13. Crocodylian and mammalian carnivore feeding traces on hominid fossils from FLK 22 and FLK NN 3, Plio-Pleistocene, Olduvai Gorge, Tanzania.

    Science.gov (United States)

    Njau, Jackson K; Blumenschine, Robert J

    2012-08-01

    Taphonomic analysis of the Olduvai Hominid (OH) 8 left foot from FLK NN Level 3 and the OH 35 left leg from FLK Level 22 (Zinjanthropus level) in Middle Bed I, Olduvai Gorge, indicates that both were fed upon by crocodiles. Both bear extensive tooth marking, including bisected tooth marks diagnostic of crocodylian feeding. The location of the bisected tooth marks on the distal tibia and the talus indicates disarticulation of the foot by crocodiles. The broken proximal ends of the tibia and fibula are more typical of feeding by a leopard-like carnivore, as is damage to the OH 7 mandible and parietals that are associated with and may derive from the same individual as OH 8. Previous work showing a close articulation of the foot and the leg has been used to suggest that the two specimens belong to the same individual despite deriving from sites separated by 200 m and slightly different stratigraphic levels according to previous work. The location and agent of tooth marking and the nature of gross damage do not refute this hypothesis, but the punctures on the talus and distal tibia differ in size and sharpness. Recent work shows that the stratigraphic discrepancy between OH 8 and OH 35 is greater than previously thought, refuting the single-individual hypothesis. Although seemingly unlikely, this denotes that two hominids represented by rarely found leg and foot elements both lost their left foot to crocodiles at nearby sites within a 6,000 year interval. We cannot determine if the hominids were preyed upon by crocodiles or mammalian carnivores. However, the carnivore damage to them and associated faunal remains suggests that high predation risk constrained hominid activities involving discard of the stone artifacts found at these sites. This finding is inconsistent with the interpretation of the sites as home bases or living floors. Published by Elsevier Ltd.

  14. Stable isotope-based Plio-Pleistocene ecosystem reconstruction of some of the earliest hominid fossil sites in the East African Rift System (Chiwondo Beds, N Malawi)

    Science.gov (United States)

    Lüdecke, Tina; Thiemeyer, Heinrich; Schrenk, Friedemann; Mulch, Andreas

    2014-05-01

    The isotope geochemistry of pedogenic carbonate and fossil herbivore enamel is a powerful tool to reconstruct paleoenvironmental conditions in particular when climate change plays a key role in the evolution of ecosystems. Here, we present the first Plio-Pleistocene long-term carbon (δ13C), oxygen (δ18O) and clumped isotope (Δ47) records from pedogenic carbonate and herbivore teeth in the Malawi Rift. These data represent an important southern hemisphere record in the East African Rift System (EARS), a key region for reconstructing vegetation patterns in today's Zambezian Savanna and correlation with data on the evolution and migration of early hominids across the Inter-Tropical Convergence Zone. As our study site is situated between the well-known hominid-bearing sites of eastern and southern Africa in the Somali-Masai Endemic Zone and Highveld Grassland it fills an important geographical gap for early hominid research. 5.0 to 0.6 Ma fluviatile and lacustrine deposits of the Chiwondo Beds (NE shore of Lake Malawi) comprise abundant pedogenic carbonate and remains of a diverse fauna dominated by large terrestrial mammals. These sediments are also home to two hominid fossil remains, a mandible of Homo rudolfensis and a maxillary fragment of Paranthropus boisei, both dated around 2.4 Ma. The Chiwondo Beds therefore document early co-existence of these two species. We evaluate δ13C data from fossil enamel of different suid, bovid, and equid species and contrast these with δ13C and δ18O values of pedogenic carbonate. We complement the latter with clumped isotope soil temperature data. Results of almost 800 pedogenic carbonate samples from over 20 sections consistently average δ13C = -8.5 ‰ over the past 5 Ma with no significant short-term δ13C excursions or long-term trends. The data from molar tooth enamel of nine individual suids of the genera Metridiochoerus, Notochoerus and Nyanzachoerus support these findings with average δ13C = -10.0 ‰. The absence

  15. Early hominid stone tool production and technical skill 2.34 Myr ago in West Turkana, Kenya.

    Science.gov (United States)

    Roche, H; Delagnes, A; Brugal, J P; Feibel, C; Kibunjia, M; Mourre, V; Texier, P J

    1999-05-06

    Well-documented Pliocene archaeological sites are exceptional. At present they are known only in East Africa, in the Hadar and Shungura formations of Ethiopia and in the Nachukui formation of Kenya. Intensive archeological survey and a series of test excavations conducted in the Nachukui formation since 1987 have led to the discovery of more than 25 archaeological sites whose ages range from 2.34 to 0.7 million years before present (Myr), and to the extensive excavation of two 2.34-Myr sites, Lokalalei 1 in 1991 and Lokalalei 2C in 1997. Lokalalei 2C yielded nearly 3,000 archaeological finds from a context of such good preservation that it was possible to reconstitute more than 60 sets of complementary matching stone artefacts. These refits, predating the Koobi Fora refits by 500 Kyr, are the oldest ever studied. Here we describe a technological analysis of the core reduction sequences, based on these refits, which allows unprecedented accuracy in the understanding of flake production processes. We can thus demonstrate greater cognitive capacity and motor skill than previously assumed for early hominids, and highlight the diversity of Pliocene technical behaviour.

  16. Direct radiocarbon dates for Vindija G1 and Velika Pećina Late Pleistocene hominid remains

    Science.gov (United States)

    Smith, Fred H.; Trinkaus, Erik; Pettitt, Paul B.; Karavanić, Ivor; Paunović, Maja

    1999-01-01

    New accelerator mass spectrometry radiocarbon dates taken directly on human remains from the Late Pleistocene sites of Vindija and Velika Pećina in the Hrvatsko Zagorje of Croatia are presented. Hominid specimens from both sites have played critical roles in the development of current perspectives on modern human evolutionary emergence in Europe. Dates of ≈28 thousand years (ka) before the present (B.P.) and ≈29 ka B.P. for two specimens from Vindija G1 establish them as the most recent dated Neandertals in the Eurasian range of these archaic humans. The human frontal bone from Velika Pećina, generally considered one of the earliest representatives of modern humans in Europe, dated to ≈5 ka B.P., rendering it no longer pertinent to discussions of modern human origins. Apart from invalidating the only radiometrically based example of temporal overlap between late Neandertal and early modern human fossil remains from within any region of Europe, these dates raise the question of when early modern humans first dispersed into Europe and have implications for the nature and geographic patterning of biological and cultural interactions between these populations and the Neandertals. PMID:10535913

  17. The diets of ungulates from the hominid fossil-bearing site of Elandsfontein, Western Cape, South Africa

    Science.gov (United States)

    Stynder, Deano D.

    2009-01-01

    The dietary regimes of 15 ungulate species from the middle Pleistocene levels of the hominid-bearing locality of Elandsfontein, South Africa, are investigated using the mesowear technique. Previous studies, using taxonomic analogy, classified twelve of the studied species as grazers ( Redunca arundinum, Hippotragus gigas, Hippotragus leucophaeus, Antidorcas recki, Homoiceras antiquus, Damaliscus aff. lunatus, Connochaetes gnou laticornutus, Rabaticerus arambourgi, Damaliscus niro, Damaliscus sp. nov., an unnamed "spiral horn" antelope and Equus capensis), one as a mixed feeder ( Taurotragus oryx) and two as browsers ( Tragelaphus strepsiceros and Raphicerus melanotis). Although results from mesowear analysis sustain previous dietary classifications in the majority of cases, five species were reclassified. Three species previously classified as grazers, were reclassified as mixed feeders ( H. gigas, D. aff. lunatus and R. arambourgi), one previously classified as a grazer, was reclassified as a browser (the "spiral horn" antelope), and one previously classified as a mixed feeder, was reclassified as a browser ( T. oryx). While current results broadly support previous reconstructions of the Elandsfontein middle Pleistocene environment as one which included a substantial C 3 grassy component, the reclassifications suggest that trees, broad-leaved bush and fynbos were probably more prominent than what was previously thought.

  18. Alluvial systems as archives for environmental change at a Hominid site with Oldowan archaeological occurrences: the Homa Peninsula, southwestern Kenya

    Science.gov (United States)

    Vincent, Thomas; Whitfield, Elizabeth; Kirby, Jason; Hunt, Christopher; Bishop, Laura; Plummer, Thomas; Ditchfield, Peter

    2016-04-01

    The Homa Peninsula, southwestern Kenya, preserves fossiliferous sedimentary sequences dating to the Plio-Pleistocene. Evidence of hominids inhabiting an open grassland setting and utilising Oldowan tools has been reported here, as well as some of the oldest known traces of hominin activity. Reconstructions of the palaeoenvironment have suggested that alluvial and lake marginal environments on a grassy plain, between wooded slopes and a permanent water body might be plausible. However, these interpretations are based only on field sedimentological analyses and stable isotope analysis at a single site on the peninsula (Kanjera South). It is the aim of this study to utilise a multiproxy approach to develop our understanding of the palaeoenvironmental characteristics here. Sediments will also be characterized at a new site (Nyayanga) through field analyses, as well as through analyses of particle size, siliceous microfossils (diatoms, phytoliths and sponge spicules), pollen and stable isotopes. By utilizing this approach, new insights into the palaeoecology, palaeohydromorphology and palaeoclimate of the locale may be revealed, expanding the limited data available to palaeoanthropological studies of Oldowan occurrences in east Africa. Efforts to refine palaeoenvironmental reconstructions of Kanjera South through particle size analysis have shown that sediments in the lower beds of the sequence are characterised by poor sorting, a bimodal distribution and sand/silty-sand grade material. This suggests rapid deposition and/or a variable hydrological regime and may represent the role of relatively unconfined ephemeral channels in the transportation and deposition of sediments. Fluvial reworking of aeolian sediments, most likely during unconfined flood events may also have occurred.

  19. Combined ESR/U-series chronology of Acheulian hominid-bearing layers at Trinchera Galeria site, Atapuerca, Spain

    International Nuclear Information System (INIS)

    Falgueres, Christophe; Bahain, Jean-Jacques; Shao, Qingfeng; Bischoff, James L.; Perez-Gonzalez, Alfredo; Ortega, Ana Isabel; Bermudez de Castro, Jose Maria; Olle, Andreu; Vallverdu, Josep; Quiles, Anita; Ghaleb, Bassam; Moreno, Davinia; Dolo, Jean-Michel; Vallverdu, Josep; Carbonell, Eudald; Arsuaga, Juan Luis

    2013-01-01

    The Sierra de Atapuerca, northern Spain, is known from many prehistoric and paleontologic sites documenting human prehistory in Europe. Three major sites, Gran Dolina, Galeria and Sima del Elefante, range in age from the oldest hominin of Western Europe dated to 1.1 to 1.3 Ma (millions of years ago) at Sima del Elefante to c.a. 0.2 Ma on the top of the Galeria archaeological sequence. Recently, a chronology based on luminescence methods (Thermoluminescence [TL] and Infrared Stimulated Luminescence [IRSL]) applied to cave sediments was published for the Gran Dolina and Galeria sites. The authors proposed for Galeria an age of 450 ka (thousands of years ago) for the units lower GIII and GII, suggesting that the human occupation there is younger than the hominid remains of Sima de los Huesos (≥530 ka) around 1 km away. In this paper, we present new results obtained by combined Electron Spin Resonance/Uranium-series (ESR/U-series) dating on 20 herbivorous teeth from different levels at the Galeria site. They are in agreement with the TL results for the upper part of the stratigraphic sequence (GIV and GIIIb), in the range of between 200 and 250 ka. But for the GIIIa to GIIb levels, the TL ages become abruptly older by 200 ka while ESR ages remain relatively constant. Finally, the TL and ESR data agree in the lowest part of the section (GIIa); both fall in the range of around 350-450 ka. Our results suggest a different interpretation for the GII, GIII and GIV units of Galeria and the upper part of Gran Dolina (TD10 and TD11) than obtained by TL. The ESR/U-series results are supported by a Bayesian analysis, which allows a better integration between stratigraphic information and radiometric data. (authors)

  20. Stable isotope analyses of tooth enamel carbonate of large herbivores from the Tugen Hills deposits: Palaeoenvironmental context of the earliest Kenyan hominids

    Science.gov (United States)

    Roche, Damien; Ségalen, Loïc; Senut, Brigitte; Pickford, Martin

    2013-11-01

    Understanding shifts in past climatic and environmental conditions are crucial for throwing light on human evolution. Available reconstructions of the palaeoecology of faunal and floral assemblages indicate that the earliest Kenyan hominids, including Orrorin tugenensis, are associated with forest landscapes. In this study, we present stable isotope data of tooth enamel carbonate of large herbivores associated with these hominids in order further to evaluate their environmental context. Fossil teeth were sampled in the Lukeino Formation (6.1-5.7 Ma, Late Miocene) and the Mabaget Formation (5.3-4.5 Ma, Early Pliocene) at the foot of the Tugen Hills (Great Rift Valley). Despite chemical changes in fossil enamel, preservation of the palaeoenvironmental signals is supported by the difference in δ18O between hippos and terrestrial fauna. Moreover, the giraffid specimen from the Mabaget Formation exhibits one of the highest δ18O values, as expected for a drought-tolerant animal. The δ13C of large herbivores indicates that the earliest Kenyan hominids inhabited a mixed C3-C4 environment as did Ardipithecus (Ethiopia) and Sahelanthropus (Chad), two early putative hominids. The Tugen Hills might have been a wooded grassland with patches of woodland. There is no record of closed-canopy forest at the time of deposition. We emphasize differences in food habits among herbivore groups. Deinotheres, nearly all elephantids and the giraffid individual had a C3 diet which reflected browsing behaviour. The intake of C4 plants prevailed for equids and gomphotheres and was consistent with grazing habits. Most hippos and suids were mixed C3-C4 feeders and consequently were generalist herbivores. Bovids and rhinos had a diet ranging from C3 to C4 plants. Variations in δ13C and δ18O among faunal assemblages suggest changes in local climate and vegetation. Moister conditions likely occurred in the Early Pliocene and the latest Miocene (ca. 5.7 Ma) than before. The C3 plant biomass

  1. The Victoria West: earliest prepared core technology in the Acheulean at Canteen Kopje and implications for the cognitive evolution of early hominids.

    Science.gov (United States)

    Li, Hao; Kuman, Kathleen; Lotter, Matt G; Leader, George M; Gibbon, Ryan J

    2017-06-01

    Prepared core technology illustrates in-depth planning and the presence of a mental template during the core reduction process. This technology is, therefore, a significant indicator in studying the evolution of abstract thought and the cognitive abilities of hominids. Here, we report on Victoria West cores excavated from the Canteen Kopje site in central South Africa, with a preliminary age estimate of approximately 1 Ma (million years ago) for these cores. Technological analysis shows that the Victoria West cores bear similarities to the 'Volumetric Concept' as defined for the Levallois, a popular and widely distributed prepared core technology from at least 200 ka (thousand years ago). Although these similarities are present, several notable differences also occur that make the Victoria West a unique and distinctive prepared core technology; these are: elongated and convergent core shapes, consistent blow directions for flake removal, a predominance of large side-struck flakes, and the use of these flakes to make Acheulean large cutting tools. This innovative core reduction strategy at Canteen Kopje extends the roots of prepared core technology to the latter part of the Early Acheulean and clearly demonstrates an increase in the cognitive abilities and complexities of hominids in this time period.

  2. A theory of marks and mind: the effect of notational systems on hominid brain evolution and child development with an emphasis on exchanges between mothers and children.

    Science.gov (United States)

    Sheridan, Susan Rich

    2005-01-01

    A model of human language requires a theory of meaningful marks. Humans are the only species who use marks to think. A theory of marks identifies children's scribbles as significant behavior, while hypothesizing the importance of rotational systems to hominid brain evolution. By recognizing the importance of children's scribbles and drawings in developmental terms as well as in evolutionary terms, a marks-based rather than a predominantly speech-based theory of the human brain, language, and consciousness emerges. Combined research in anthropology, primatology, art history, neurology, child development (including research with deaf and blind children), gender studies and literacy suggests the importance of notational systems to human language, revealing the importance of mother/child interactions around marks and sounds to the development of an expressive, communicative, symbolic human brain. An understanding of human language is enriched by identifying marks carved on bone 1.9 million years ago as observational lunar calendar-keeping, pushing proto-literacy back dramatically. Neurologically, children recapitulate the meaningful marks of early hominins when they scribble and draw, reminding us that literacy belongs to humankind's earliest history. Even more than speech, such meaningful marks played - and continue to play - decisive roles in human brain evolution. The hominid brain required a model for integrative, transformative neural transfer. The research strongly suggests that humankind's multiple literacies (art, literature, scientific writing, mathematics and music) depended upon dyadic exchanges between hominid mothers and children, and that this exchange and sharing of visuo-spatial information drove the elaboration of human speech in terms of syntax, grammar and vocabulary. The human brain was spatial before it was linguistic. The child scribbles and draws before it speaks or writes. Children babble and scribble within the first two years of life. Hands

  3. Hétérochronies dans l'évolution des hominidés. Le développement dentaire des australopithécines «robustes»Heterochronic process in hominid evolution. The dental development in 'robust' australopithecines.

    Science.gov (United States)

    Ramirez Rozzi, Fernando V.

    2000-10-01

    Heterochrony is defined as an evolutionary modification in time and in the relative rate of development [6]. Growth (size), development (shape), and age (adult) are the three fundamental factors of ontogeny and have to be known to carry out a study on heterochronies. These three factors have been analysed in 24 Plio-Pleistocene hominid molars from Omo, Ethiopia, attributed to A. afarensis and robust australopithecines ( A. aethiopicus and A. aff. aethiopicus) . Molars were grouped into three chronological periods. The analysis suggests that morphological modifications through time are due to heterochronic process, a neoteny ( A. afarensis - robust australopithecine clade) and a time hypermorphosis ( A. aethiopicus - A. aff. aethiopicus).

  4. Freshwater on the route of hominids "out of Africa" during the last interglacial revealed by U-Th in northern Red Sea fossil reefs

    Science.gov (United States)

    Lazar, B.; Stein, M.; Agnon, A.; Shaked, Y.

    2012-04-01

    The migration of Anatomically Modern Hominids (AMH) "out of Africa" is a fundamental problem in the study of human culture concerning that the route passed through the presently hyperarid deserts surrounding the Red Sea. Here, we outline the evidence for significant presence of freshwater in a well developed phreatic coastal aquifer along the Red Sea shores during the last interglacial period. The fringing coral reefs were tectonically uplifted through the freshwater lens resulting in extensive recrystallization of reef framework from the primary aragonite into calcite. We developed a novel open-system U-Th dating methodology that enabled us estimating two ages for the calcitic reef terrace: 1. The original age of the reef terrace, deposited at ~190 ka BP; and 2. the time of freshwater recrystallization (from the primary aragonite into calcite) at ~140 ka BP. The age of freshwater recrystallization is consistent with other geological lines of evidence placing the time of AMH migration "out of Africa" at the onset of the last interglacial. It is likely therefore that during that time the hyperarid Red Sea area was wetter than today facilitating the migration of AMH to Europe and Asia.

  5. A reassessment of the study of cut mark patterns to infer hominid manipulation of fleshed carcasses at the Flk Zinj 22 site, Olduvai Gorge, Tanzania

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    Domínguez-Rodrigo, Manuel

    1997-12-01

    Full Text Available Previous experimental studies on cut marks have suggested that cut mark percentages and their anatomical distribution (based on element type and bone section type could be used to differentiate primary access to fleshed carcasses from secondary access to defleshed carcasses. In this study, the experimental sample of this type of studies is increased and further data are included to infer a primary access by hominids to carcasses at the FLK Zinj site of Olduvai.

    Estudios experimentales anteriores sobre marcas de corte han sugerido que los porcentajes de marcas de corte y su distribución (basada en tipo de hueso y tipo de sección ósea podrían usarse para diferenciar un acceso primario a carcasas con carne de un acceso secundario a carcasas descarnadas. En este estudio semejante muestra experimental se ve ampliada y se muestran más datos que sirven para inferir que los homínidos tuvieron un acceso primario a las carcasas representadas en el yacimiento FLK Zinj de Olduvai.

  6. High-resolution U-series dates from the Sima de los Huesos hominids yields 600 +∞-66: implications for the evolution of the early Neanderthal lineage

    Science.gov (United States)

    Bischoff, James L.; Williams, Ross W.; Rosenbauer, Robert J.; Aramburu, Arantza; Arsuaga, Juan Luis; Garcia, Nuria; Cuenca-Bescos, Gloria

    2007-01-01

    The Sima de los Huesos site of the Atapuerca complex near Burgos, Spain contains the skeletal remains of at least 28 individuals in a mud-breccia underlying an accumulation of the Middle Pleistocene cave bear (Ursus deningeri). We report here on new high-precision dates on the recently discovered speleothem SRA-3 overlaying human bones within the Sima de los Huesos. Earlier analyses of this speleothem by TIMS (thermal-ionization mass-spectrometry) showed the lower part to be indistinguishable from internal isotopic equilibrium at the precision of the TIMS instrumentation used, yielding minimum age of 350 kyr (kyr = 103 yr before present). Reanalysis of six samples of SRA-3 by inductively-coupled plasma-multicollector mass-spectrometry (ICP-MS) produced high-precision analytical results allowing calculation of finite dates. The new dates cluster around 600 kyr. A conservative conclusion takes the lower error limit ages as the minimum age of the speleothem, or 530 kyr. This places the SH hominids at the very beginnings of the Neandertal evolutionary lineage.

  7. The early Pleistocene deciduous hominid molar FS-72 from the Sangiran Dome of Java, Indonesia: A taxonomic reappraisal based on its comparative endostructural characterization.

    Science.gov (United States)

    Zanolli, Clément; Grine, Frederick E; Kullmer, Ottmar; Schrenk, Friedemann; Macchiarelli, Roberto

    2015-08-01

    Among the ten fossil hominid deciduous teeth reported so far from the Pleistocene sediments of the Sangiran Dome of Java are two isolated lower second molars: specimens PCG.2 from the Kabuh Formation and FS-72 from the Pucangan Formation. While PCG.2 appears to be certainly attributable to Homo erectus, FS-72 is somewhat more problematic, even though it is commonly listed within the Indonesian H. erectus hypodigm. Largely because of its large size, it was originally attributed to Meganthropus paleojavanicus. Subsequent study highlighted a set of metric and nonmetric crown features also found in Australopith and African early Homo (notably H. habilis) homologues. An additional problem with the taxonomic assignment of isolated teeth from the Pleistocene of Java is the presence of Pongo in these same deposits. To assess the taxonomic affinity of FS-72, we investigated its inner structure (tissue proportions and enamel-dentine junction morphology) by using techniques of 2-3D virtual imaging coupled with geometric morphometric analyses. The results show that FS-72 has thinner enamel compared to fossil and recent humans and that its topographic repartition more closely follows the pongine pattern. It also exhibits a Pongo-like elongated morphology of the enamel-dentine junction, with proportionally lower and mesiodistally spaced dentine horns. Given the morphological and metric similarities between fossil orangutan and H. erectus molars, we tested the hypothesis that its internal morphology more closely resembles the patterns evinced by PCG.2 and modern humans than Pongo. Accordingly, we consider that FS-72 more likely represents a dm2 of Pongo rather than Homo. © 2015 Wiley Periodicals, Inc.

  8. Relationship of squamosal suture to asterion on external skull surfaces versus endocasts of pongids: implications for Hadar early hominid AL 162-28.

    Science.gov (United States)

    Falk, D; Hildebolt, C; Vannier, M

    1994-04-01

    The relationship between the squamosal suture and asterion was quantified in 15 hemispheres of eight chimpanzee endocasts that were aligned in the conventional lateral view (i.e., with frontal pole [FP]-occipital pole [OP] horizontal). Using a three-dimensional digitizer, x, y, and z coordinates were collected for the highest and lowest points of the squamosal suture, and the most rostral point of the suture approximate to the coronal suture. Our results were compared to a similar study of the squamosal suture on the external surfaces of chimpanzee skulls that were oriented in the Frankfurt horizontal (Holloway and Shapiro, 1992). The relationship between the squamosal suture and asterion differs markedly between the outsides of skulls and endocasts. Whereas the squamosal suture is very rarely below asterion on the external skull, we found that most of the squamosal suture is located inferior to asterion on endocasts. We also found that the squamosal suture courses approximately 2.0 mm lower on the right side than the left. (An asymmetry of the same magnitude was reported for the external skull but, curiously, in the opposite direction.) It may be that a lowered right squamosal endosuture on chimpanzee endocasts is associated with earlier closure on that side. The discrepancy in results for the external skull versus endocast is partially attributable to orienting chimpanzee skulls in the Frankfurt horizontal, which usually results in the endocasts being tilted so that FP is above OP, i.e., FP-OP is not parallel with the Frankfurt horizontal. Falk's (1985) orientation of the early hominid endocast from Hadar (AL 162-28) is consistent with data determined from endocasts of chimpanzees.

  9. Combined ESR/U-series chronology of Acheulian hominid-bearing layers at Trinchera Galería site, Atapuerca, Spain.

    Science.gov (United States)

    Falguères, Christophe; Bahain, Jean-Jacques; Bischoff, James L; Pérez-González, Alfredo; Ortega, Ana Isabel; Ollé, Andreu; Quiles, Anita; Ghaleb, Bassam; Moreno, Davinia; Dolo, Jean-Michel; Shao, Qingfeng; Vallverdú, Josep; Carbonell, Eudald; Bermúdez de Castro, Jose María; Arsuaga, Juan Luis

    2013-08-01

    The Sierra de Atapuerca, northern Spain, is known from many prehistoric and palaeontological sites documenting human prehistory in Europe. Three major sites, Gran Dolina, Galería and Sima del Elefante, range in age from the oldest hominin of Western Europe dated to 1.1 to 1.3 Ma (millions of years ago) at Sima del Elefante to c.a. 0.2 Ma on the top of the Galería archaeological sequence. Recently, a chronology based on luminescence methods (Thermoluminescence [TL] and Infrared Stimulated Luminescence [IRSL]) applied to cave sediments was published for the Gran Dolina and Galería sites. The authors proposed for Galería an age of 450 ka (thousands of years ago) for the units lower GIII and GII, suggesting that the human occupation there is younger than the hominid remains of Sima de los Huesos (>530 ka) around 1 km away. In this paper, we present new results obtained by combined Electron Spin Resonance/Uranium-series (ESR/U-series) dating on 20 herbivorous teeth from different levels at the Galería site. They are in agreement with the TL results for the upper part of the stratigraphic sequence (GIV and GIIIb), in the range of between 200 and 250 ka. But for the GIIIa to GIIb levels, the TL ages become abruptly older by 200 ka while ESR ages remain relatively constant. Finally, the TL and ESR data agree in the lowest part of the section (GIIa); both fall in the range of around 350-450 ka. Our results suggest a different interpretation for the GII, GIII and GIV units of Galería and the upper part of Gran Dolina (TD10 and TD11) than obtained by TL. The ESR/U-series results are supported by a Bayesian analysis, which allows a better integration between stratigraphic information and radiometric data. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Megalake Chad impact on climate and vegetation during the late Pliocene and the mid-Holocene

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    C. Contoux

    2013-07-01

    Full Text Available Given the growing evidence for megalakes in the geological record, assessing their impact on climate and vegetation is important for the validation of palaeoclimate simulations and therefore the accuracy of model–data comparison in lacustrine environments. Megalake Chad (MLC occurrences are documented not only for the mid-Holocene but also for the Mio-Pliocene (Schuster et al., 2009. At this time, the surface covered by water would have reached up to ~350 000 km2 (Ghienne et al., 2002; Schuster et al., 2005; Leblanc et al., 2006, making it an important evaporation source, possibly modifying climate and vegetation in the Chad Basin. We investigated the impact of such a giant continental water area in two different climatic backgrounds within the Paleoclimate Model Intercomparison Project phase 3 (PMIP3: the late Pliocene (3.3 to 3 Ma, i.e. the mid-Piacenzian warm period and the mid-Holocene (6 kyr BP. In all simulations including MLC, precipitation is drastically reduced above the lake surface because deep convection is inhibited by overlying colder air. Meanwhile, convective activity is enhanced around MLC because of the wind increase generated by the flat surface of the megalake, transporting colder and moister air towards the eastern shore of the lake. The effect of MLC on precipitation and temperature is not sufficient to widely impact vegetation patterns. Nevertheless, tropical savanna is present in the Chad Basin in all climatic configurations, even without MLC presence, showing that the climate itself is the driver of favourable environments for sustainable hominid habitats.

  11. Paléocontraintes et déformations syn- et post-collision Afrique Europe identifiées dans la couverture mésozoïque et cénozoïque du Haut Atlas occidental (Maroc)Syn- and post-collision Africa Europe palaeostresses and deformations identified in the West High-Atlas Mesozoic and Cenozoic cover (Morocco)

    Science.gov (United States)

    Amrhar, Mostafa

    Palaeostresses and deformation axis reconstruction related to the intracontinental High-Atlas uplift evidences two shortening phases from Upper Cretaceous to Quaternary. The first compression is oriented N20-30°E and is Maastrichtian to Oligocene age; the second one, oriented N120-160°E, is syn-Mio-Pliocene. Tectonic inversion of the lateral to compressive Jurassic regime is contemporaneous with the beginning of Africa and Europe collision. Rotation of the Mio-Pliocene shortening orientation could be linked to the change of the convergence direction between the Africa and Europe plates. To cite this article: M. Amrhar, C. R. Geoscience 334 (2002) 279-285.

  12. Messinian events in the Black Sea

    NARCIS (Netherlands)

    van Baak, Christiaan G C; Radionova, Eleanora P.; Golovina, Larisa A.; Raffi, Isabella; Kuiper, Klaudia F.; Vasiliev, Iuliana; Krijgsman, Wout

    2015-01-01

    Past hydrological interactions between the Mediterranean Sea and Black Sea are poorly resolved due to complications in establishing a high-resolution time frame for the Black Sea. We present a new greigite-based magnetostratigraphic age model for the Mio-Pliocene deposits of DSDP Hole 380/380A,

  13. Explaining the imperfection of the molecular clock of hominid mitochondria.

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    Eva-Liis Loogväli

    Full Text Available The molecular clock of mitochondrial DNA has been extensively used to date various genetic events. However, its substitution rate among humans appears to be higher than rates inferred from human-chimpanzee comparisons, limiting the potential of interspecies clock calibrations for intraspecific dating. It is not well understood how and why the substitution rate accelerates. We have analyzed a phylogenetic tree of 3057 publicly available human mitochondrial DNA coding region sequences for changes in the ratios of mutations belonging to different functional classes. The proportion of non-synonymous and RNA genes substitutions has reduced over hundreds of thousands of years. The highest mutation ratios corresponding to fast acceleration in the apparent substitution rate of the coding sequence have occurred after the end of the Last Ice Age. We recalibrate the molecular clock of human mtDNA as 7990 years per synonymous mutation over the mitochondrial genome. However, the distribution of substitutions at synonymous sites in human data significantly departs from a model assuming a single rate parameter and implies at least 3 different subclasses of sites. Neutral model with 3 synonymous substitution rates can explain most, if not all, of the apparent molecular clock difference between the intra- and interspecies levels. Our findings imply the sluggishness of purifying selection in removing the slightly deleterious mutations from the human as well as the Neandertal and chimpanzee populations. However, for humans, the weakness of purifying selection has been further exacerbated by the population expansions associated with the out-of Africa migration and the end of the Last Ice Age.

  14. Origin of hominids: European or African origin, neither or both?

    Directory of Open Access Journals (Sweden)

    Senut, B.

    2011-12-01

    Full Text Available For the last twenty years, some scientists have suggested that the African ape and humans lineages emerged in Europe, a scenario known as the “Back to Africa Hypothesis”. Even though hominoids were widespread in Eurasia during the Middle and Upper Miocene due to the tropical conditions which prevailed in this region, we cannot dismiss the fact that they were present in Africa (contra some authors. Actually, they were highly diverse at that same time (at least 10 lineages represented even if the fossil record is less complete than in Eurasia. Postcranial elements from African species suggest that some features of modern hominoids were already present in the Lower and Middle Miocene of Africa and were not restricted to European ones. Considering the available evidence, it is not possible at this stage to favour a European origin over an African one. Hominoids were living in the tropical areas of Northern Africa and Southern Eurasia and faunal exchanges between the two continents occurred throughout the Middle and Upper Miocene, as the Tethys did not act as an effective barrier to interchanges between Europe and Asia.

    Durante los últimos veinte años, algunos científicos han sugerido que los grandes monos africanos y los linajes humanos surgieron en Europa, un escenario conocido como la “ Hipótesis de la vuelta a Africa”. A pesar de que los homínidos se extendieron en Eurasia durante el Mioceno Medio y Superior debido a las condiciones tropicales que prevalecian en esta region, no podemos descartar el hecho de que ellos estuvieron presentes en Africa (contra algunos autores. En realidad, ellos tuvieron una alta diversidad al mismo tiempo (al menos 10 líneas representadas, incluso si el registro fosil es menos completo que el de Eurasia. Elementos postcraneales de especies africanas sugieren que en algunos carácteres los homínidos modernos estaban ya presentes en el Mioceno Inferior y Medio de Africa, no sólo restringidos a las formas europeas. Teniendo en cuenta las evidencias disponibles, no es posible, en el estado actual de conocimiento, favorecer más un origen europeo que otro africano. Los homínidos vivieron en áreas tropicales del Norte de África y del Sur de Eurasia, cambios faunísticos se sucedieron entre los dos continents a lo largo del Mioceno Medio y Superior, sin que el Tetis actuase como una barrera efectiva a los intercambios entre Europa y Asia.

  15. Perikymata spacing and distribution on hominid anterior teeth.

    Science.gov (United States)

    Dean, M C; Reid, D J

    2001-11-01

    We documented the spacing and distribution of perikymata on the buccal enamel surface of fossil hominin anterior teeth with reference to a sample of modern human and modern great ape teeth. A sample of 27 anterior teeth attributed to Australopithecus (5 to A. afarensis, 22 to A. africanus) and of 33 attributed to Paranthropus (6 to P. boisei, and 27 to P. robustus) were replicated and sputter-coated with gold to enable reflected light microscopy of their surface topography. Anterior teeth were then divided into 10 equal divisions of buccal crown height. The total perikymata count in each division of crown height was recorded using a binocular microscope fitted with a vernier micrometer eyepiece. Then the mean number of perikymata per millimeter was calculated for each division. Similar comparative data for a modern sample of 115 unworn human anterior teeth and 30 African great ape anterior teeth were collected from ground sections. Perikymata counts in each taxon (together with either known or presumed periodicities of perikymata) were then used to estimate enamel formation times in each division of crown height, for all anterior tooth types combined. The distributions of these estimates of time taken to form each division of crown height follow the same trends as the actual perikymata counts and differ between taxa in the same basic way. The distinction between modern African great apes and fossil hominins is particularly clear. Finally, we calculated crown formation times for each anterior tooth type by summing cuspal and lateral enamel formation times. Estimates of average crown formation times in australopiths are shorter than those calculated for both modern human and African great ape anterior teeth. The data presented here provide a better basis for exploring differences in perikymata spacing and distribution among fossil hominins, and provide the first opportunity to describe four specimens attributed to Homo in this context. Preliminary data indicate that differences may exist among the species attributed to early Homo, especially between Homo ergaster and Homo rudolfensis on the one hand, and Homo habilis sensu strico on the other. Copyright 2001 Wiley-Liss, Inc.

  16. Unusual death of millipedes (Diplopoda) towards the north of the Varkala Cliff section near Papanasam, Kerala, India

    OpenAIRE

    P.K. Sarkar; S. N. Mude, Madhuri Ukey

    2011-01-01

    The cliff section at Varkala, Kerala consisting of clay, lignite band, clay, sandy-clay, sandstone of Mio-Pliocene age. This sedimentary sequence is overlain by a thick laterite. Above the lower lignite band, in the exposed clay beds several struggling and dead millipedes can be observed. Their death is probably due to the action of dehydration related to the sulphuric water infiltration in the sediments. However, it still remains a mystery why these millipedes choose such a toxic environment...

  17. Polygenetic development and paleoenvironmental implications of a Pleistocene calcrete at Tongoy, central northern Chile.

    OpenAIRE

    M. Pfeiffer; J. Le Roux; H. Kemnitz

    2011-01-01

    The Norte Chico Region, in central northern Chile, is a particularly sensitive area to Quaternary climate changes because of its extreme climatic gradients. However, very little has been done to determine the late Pleistocene climatic conditions of the area. Calcretes are known to be important repositories of information on past ecosystems and environments. In the Tongoy paleobay, a series of four marine beach terraces have developed over a Mio-Pliocene calcareous formation since MIS 11 to th...

  18. Fruits and foliage of Pueraria (Leguminosae, Papilionoideae) from the Neogene of Eurasia and their biogeographic implications.

    Science.gov (United States)

    Wang, Qi; Manchester, Steven R; Dilcher, David L

    2010-12-01

    Pueraria (Leguminosae, Papilionoideae) is native in East Asia, South Asia, Southeast Asia, and Oceania and is well known as a rampant invasive weed in the southeastern United States (P. montana; better known as kudzu), but relatively little is known about its early evolution and biogeographic origin. • On the basis of comparative analyses of the fruit and leaflet architecture of closely related extant and fossil taxa, we studied the fossil history and biogeography of Pueraria. • Fossil Pueraria is recognized on the basis of distinctive fruit and foliage from the Mio-Pliocene of middle latitudes in China, Japan, Abkhazia, and Croatia. Recognition of P. miothunbergiana from the Mio-Pliocene of China and Japan is reinforced by a trifoliolate leaf as well as isolated lateral and terminal leaflets. Pueraria shanwangensis sp. nov. represents the first recognition of fossil Pueraria fruits. This fruit species co-occurs with P. miothunbergiana in the Middle Miocene Shanwang flora and possibly represents the same population. Pueraria maxima (Unger) comb. nov., previously named as Dolichites maximus or Desmodium maximum, is recognized on the basis of leaflets from the Miocene of Croatia and Abkhazia. Other prior fossil reports of Pueraria and Dolichites are reevaluated. • Pueraria had begun to diversify by at least the Middle Miocene and had spread into the Mio-Pliocene subtropical and temperate floras of the Balkan Peninsula, the Caucasus, and eastern Asia, which suggests the present diversity of this genus in tropical Asia and Oceania might have originated from the mid-latitudes of Eurasia.

  19. Evolution of Lake Chad Basin hydrology during the mid-Holocene: A preliminary approach from lake to climate modelling

    Science.gov (United States)

    Sepulchre, Pierre; Schuster, Mathieu; Ramstein, Gilles; Krinnezr, Gerhard; Girard, Jean-Francois; Vignaud, Patrick; Brunet, Michel

    2008-03-01

    During the mid-Holocene (6000 yr Before Present, hereafter yr BP) the Chad Basin was occupied by a large endoreic lake, called Lake Mega-Chad. The existence of this lake at that time seems linked to increased monsoonal moisture supply to the Sahel and the Sahara, which in turn was probably ultimately caused by variations in the orbital forcing and higher temperature gradients between ocean and continent. This study provides a synthesis of several works carried out on the Lake Chad Basin and analyses the results of a simulation of the mid-Holocene climate with an Atmosphere General Circulation Model (LMDZ for Laboratoire de Météorologie Dynamique, IPSL Paris), with emphasis on the possible conditions leading to the existence of Lake Mega-Chad. The aim is to define the best diagnostics to understand which mechanisms lead to the existence of the large lake. This paper is the first step of an ongoing work that intends to understand the environmental conditions that this part of Africa experienced during the Upper Miocene (ca. 7 Ma BP), an epoch that was contemporaneous with the first known hominids. Indeed, early hominids of Lake Chad Basin, Australopithecus bahrelghazali [ Brunet, M., et al., 1995. The first australopithecine 2500 kilometers west of the Rift-Valley (Chad). Nature, 378(6554): 273-275] and Sahelanthropus tchadensis [Brunet, M., et al., 2002. A new hominid from the Upper Miocene of Chad, central Africa. Nature, 418(6894): 145-151; Brunet, M., et al., 2005. New material of the earliest hominid from the Upper Miocene of Chad. Nature, 434(7034): 752-755] are systematically associated with wet episodes that are documented for 7 Ma BP [Vignaud, P., et al., 2002. Geology and palaeontology of the Upper Miocene Toros-Menalla hominid locality, Chad. Nature, 418(6894): 152-155] and testified by extended lacustrine deposits (diatomites, pelites, various aquatic fauna). Because the mid-Holocene was the last such mega-lake episode, our aim here is to assess the

  20. Bone strength and athletic ability in hominids: Ardipithecus ramidus to Homo sapiens

    Science.gov (United States)

    Lee, S. A.

    2013-03-01

    The ability of the femur to resist bending stresses is determined by its midlength cross-sectional geometry, its length and the elastic properties of the mineral part of the bone. The animal's athletic ability, determined by a ``bone strength index,'' is limited by this femoral bending strength in relation to the loads on the femur. This analysis is applied to the fossil record for Homo sapiens, Homo neanderthalensis, Homo erectus, Homo habilis, Australopithecus afarensis and Ardipithecus ramidus. Evidence that the femoral bone strength index of modern Homo sapiens has weakened over the last 50,000 years is found.

  1. Bone strength and athletic ability in hominids: Ardipithecus ramidus to Homo sapiens

    Science.gov (United States)

    Lee, Scott

    2012-10-01

    A methodology for the evaluation of the athletic ability of animals based on the strength of their femur and their body mass is developed. The ability of the femur to resist bending stresses is determined by its midlength cross-sectional geometry, its length and the elastic properties of the mineral part of the bone. The animal's athletic ability, determined by a ``bone strength index,'' is limited by this femoral bending strength in relation to the loads on the femur. This analysis is applied to the fossil record for Homo sapiens, Homo neanderthalensis, Homo erectus, Homo habilis, Australopithecus afarensis and Ardipithecus ramidus. Evidence that the femoral bone strength index of modern Homo sapiens has weakened over the last 50,000 years is found.

  2. Y-Chromosome variation in hominids: intraspecific variation is limited to the polygamous chimpanzee.

    Directory of Open Access Journals (Sweden)

    Gabriele Greve

    Full Text Available BACKGROUND: We have previously demonstrated that the Y-specific ampliconic fertility genes DAZ (deleted in azoospermia and CDY (chromodomain protein Y varied with respect to copy number and position among chimpanzees (Pan troglodytes. In comparison, seven Y-chromosomal lineages of the bonobo (Pan paniscus, the chimpanzee's closest living relative, showed no variation. We extend our earlier comparative investigation to include an analysis of the intraspecific variation of these genes in gorillas (Gorilla gorilla and orangutans (Pongo pygmaeus, and examine the resulting patterns in the light of the species' markedly different social and mating behaviors. METHODOLOGY/PRINCIPAL FINDINGS: Fluorescence in situ hybridization analysis (FISH of DAZ and CDY in 12 Y-chromosomal lineages of western lowland gorilla (G. gorilla gorilla and a single lineage of the eastern lowland gorilla (G. beringei graueri showed no variation among lineages. Similar findings were noted for the 10 Y-chromosomal lineages examined in the Bornean orangutan (Pongo pygmaeus, and 11 Y-chromosomal lineages of the Sumatran orangutan (P. abelii. We validated the contrasting DAZ and CDY patterns using quantitative real-time polymerase chain reaction (qPCR in chimpanzee and bonobo. CONCLUSION/SIGNIFICANCE: High intraspecific variation in copy number and position of the DAZ and CDY genes is seen only in the chimpanzee. We hypothesize that this is best explained by sperm competition that results in the variant DAZ and CDY haplotypes detected in this species. In contrast, bonobos, gorillas and orangutans-species that are not subject to sperm competition-showed no intraspecific variation in DAZ and CDY suggesting that monoandry in gorillas, and preferential female mate choice in bonobos and orangutans, probably permitted the fixation of a single Y variant in each taxon. These data support the notion that the evolutionary history of a primate Y chromosome is not simply encrypted in its DNA sequences, but is also shaped by the social and behavioral circumstances under which the specific species has evolved.

  3. Longevity and plasticity of CFTR provide an argument for noncanonical SNP organization in hominid DNA.

    Directory of Open Access Journals (Sweden)

    Aubrey E Hill

    Full Text Available Like many other ancient genes, the cystic fibrosis transmembrane conductance regulator (CFTR has survived for hundreds of millions of years. In this report, we consider whether such prodigious longevity of an individual gene--as opposed to an entire genome or species--should be considered surprising in the face of eons of relentless DNA replication errors, mutagenesis, and other causes of sequence polymorphism. The conventions that modern human SNP patterns result either from purifying selection or random (neutral drift were not well supported, since extant models account rather poorly for the known plasticity and function (or the established SNP distributions found in a multitude of genes such as CFTR. Instead, our analysis can be taken as a polemic indicating that SNPs in CFTR and many other mammalian genes may have been generated--and continue to accrue--in a fundamentally more organized manner than would otherwise have been expected. The resulting viewpoint contradicts earlier claims of 'directional' or 'intelligent design-type' SNP formation, and has important implications regarding the pace of DNA adaptation, the genesis of conserved non-coding DNA, and the extent to which eukaryotic SNP formation should be viewed as adaptive.

  4. Impacts of curatorial and research practices on the preservation of fossil hominid remains.

    Science.gov (United States)

    Le Cabec, Adeline; Toussaint, Michel

    2017-12-30

    Fossil remains are the only physical evidence of past forms of life which researchers can use to study the evolutionary biology of a species, especially regarding the human lineage. We review and consider the way in which the conditions surrounding a fossil's discovery and its use for scientific research impacts its long-term preservation. The deterioration of the body starts soon after death, continues in the sediments and only a subsample of the anatomical elements will persist and may finally be unearthed by archeologists. From their recovery onwards, fossil remains are exposed to many sources of further damage: from handling, restoration, measuring to invasive sampling. On the one hand, curators are faced with the inherent challenge of balancing their responsibility to protect fossil specimens with allowing researchers to perform specific analyses or invasive sampling detrimental to the preservation of the fossil. On the other hand, scientists may find their analyses complicated by multiple factors including taphonomy, or restoration techniques (e.g., consolidants, cleaning chemicals). We provide several historical examples illustrating the complex nature of the factors acting on fossil preservation. We discuss concerns about producing and sharing (digital) data from fossils. Finally, we also suggest and support some curatorial practices which maximize the traceability of treatments underwent by a fossil.

  5. Primates, Lice and Bacteria: Speciation and Genome Evolution in the Symbionts of Hominid Lice.

    Science.gov (United States)

    Boyd, Bret M; Allen, Julie M; Nguyen, Nam-Phuong; Vachaspati, Pranjal; Quicksall, Zachary S; Warnow, Tandy; Mugisha, Lawrence; Johnson, Kevin P; Reed, David L

    2017-07-01

    Insects with restricted diets rely on symbiotic bacteria to provide essential metabolites missing in their diet. The blood-sucking lice are obligate, host-specific parasites of mammals and are themselves host to symbiotic bacteria. In human lice, these bacterial symbionts supply the lice with B-vitamins. Here, we sequenced the genomes of symbiotic and heritable bacterial of human, chimpanzee, gorilla, and monkey lice and used phylogenomics to investigate their evolutionary relationships. We find that these symbionts have a phylogenetic history reflecting the louse phylogeny, a finding contrary to previous reports of symbiont replacement. Examination of the highly reduced symbiont genomes (0.53-0.57 Mb) reveals much of the genomes are dedicated to vitamin synthesis. This is unchanged in the smallest symbiont genome and one that appears to have been reorganized. Specifically, symbionts from human lice, chimpanzee lice, and gorilla lice carry a small plasmid that encodes synthesis of vitamin B5, a vitamin critical to the bacteria-louse symbiosis. This plasmid is absent in an old world monkey louse symbiont, where this pathway is on its primary chromosome. This suggests the unique genomic configuration brought about by the plasmid is not essential for symbiosis, but once obtained, it has persisted for up to 25 My. We also find evidence that human, chimpanzee, and gorilla louse endosymbionts have lost a pathway for synthesis of vitamin B1, whereas the monkey louse symbiont has retained this pathway. It is unclear whether these changes are adaptive, but they may point to evolutionary responses of louse symbionts to shifts in primate biology. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  6. Hominid and carnivore activity at Middle and Upper Paleolithic cave sites in eastern Spain.

    Directory of Open Access Journals (Sweden)

    John Lindly

    1988-01-01

    Full Text Available Recientes investigaciones zooarqueológicas han desarrollado métodos para distinguir entre residuos óseos producidos por depredadores carnívoros y animales de carroña, y residuos semejantes producidos por homínidos. Estas metodologías han sido aplicadas a yacimientos Pleistocénicos en Africa, mientras que sólo se han comenzado a utilizar para yacimientos paleolíticos de Europa Occidental. Un análisis preliminar del papel jugado por los carnívoros en la deposición del material faunístico en el norte de España (Straus, 1982 sugiere un alta implicación de carnívoros en la formación de depósitos musterienses con una disminución de su papel en el Paleolítico Superior. En este estudio, las relaciones entre carnívoros y ungulados de los yacimientos del Paleolítico Medio (Los Casares, Cova Negra y tres del Superior (Parpalló, Les Mallaetes, Volcán del Faro de la España levantina confirman la validez de este modelo. Sin embargo, métodos más precisos como el análisis de frecuencias de las partes del cuerpo y medidas de la atrición de los conjuntos faunísticos sugieren una implicación constante o mayor de carnívoros en la formación de estos conjuntos a lo largo del   tiempo, indicando que anteriores interpretaciones sobre estrategias de subsistencias en estos yacimientos pueden ser sospechosas e incluso completamente equivocadas.

  7. Evolution of the auditory ossicles in extant hominids: metric variation in African apes and humans

    Science.gov (United States)

    Quam, Rolf M; Coleman, Mark N; Martínez, Ignacio

    2014-01-01

    The auditory ossicles in primates have proven to be a reliable source of phylogenetic information. Nevertheless, to date, very little data have been published on the metric dimensions of the ear ossicles in African apes and humans. The present study relies on the largest samples of African ape ear ossicles studied to date to address questions of taxonomic differences and the evolutionary transformation of the ossicles in gorillas, chimpanzees and humans. Both African ape taxa show a malleus that is characterized by a long and slender manubrium and relatively short corpus, whereas humans show the opposite constellation of a short and thick manubrium and relatively long corpus. These changes in the manubrium are plausibly linked with changes in the size of the tympanic membrane. The main difference between the incus in African apes and humans seems to be related to changes in the functional length. Compared with chimpanzees, human incudes are larger in nearly all dimensions, except articular facet height, and show a more open angle between the axes. The gorilla incus resembles humans more closely in its metric dimensions, including functional length, perhaps as a result of the dramatically larger body size compared with chimpanzees. The differences between the stapedes of humans and African apes are primarily size-related, with humans being larger in nearly all dimensions. Nevertheless, some distinctions between the African apes were found in the obturator foramen and head height. Although correlations between metric variables in different ossicles were generally lower than those between variables in the same bone, variables of the malleus/incus complex appear to be more strongly correlated than those of the incus/stapes complex, perhaps reflecting the different embryological and evolutionary origins of the ossicles. The middle ear lever ratio for the African apes is similar to other haplorhines, but humans show the lowest lever ratio within primates. Very low levels of sexual dimorphism were found in the ossicles within each taxon, but some relationship with body size and several dimensions of the ear bones was found. Several of the metric distinctions in the incus and stapes imply a slightly different articulation of the ossicular chain within the tympanic cavity in African apes compared with humans. The limited auditory implications of these metric differences in the ossicles are also discussed. Finally, the results of this study suggest that several plesiomorphic features for apes may be retained in the ear bones of the early hominin taxa Australopithecus and Paranthropus as well as in the Neandertals. PMID:24845949

  8. Development of the palatal size in Pan troglodytes, Hominids and Homo sapiens.

    Science.gov (United States)

    Arnold, W H; Zoellner, A; Sebastian, T

    2004-12-01

    As the hard palate plays an important role in speech production it was the aim of this study whether similarities or dissimilarities in palatal size may allow conclusions about the ability to produce speech in the extant investigated species. The palatal size of Pan troglodytes, Homo sapiens, Australopithecus afarensis, Australopithecus africanus, Australopithecus robustus, Australopithecus boisei, Homo erectus, Homo neanderthalensis and Cro-Magnon has been investigated using euclidian distance matrix analysis (EDMA) and thin-plate-spline analysis. The results show that the palatal size of all australopithecine specimens and H. erectus is very similar to that of P toglodytes, whereas the palatal size of H. neanderthalensis more closely resembles that of H. sapiens. Postnatal development of palatal size in P troglodytes is different from that of H. sapiens. In P troglodytes not only the size of the palate changes but also the form. In H. sapiens there is little change in form, but a continuos uniform growth from infantile to adult specimens. From the results we conclude that in all australopithecine samples which have been investigated, the palatal size is similar to that of P troglodytes. Therefore, it is unlikely that austraopithecine individuals were capable of producing vowels and consonants. The palatal size of H. neandethalensis and Cro-Magnon is similar to that of H. sapiens which may indicate the possibility that they were capable of speech production.

  9. Thermal ionization mass spectrometry U-series dating of a hominid site near Nanjing, China

    Science.gov (United States)

    Zhao, Jian-Xin; Hu, Kai; Collerson, Kenneth D.; Xu, Han-Kui

    2001-01-01

    Mass spectrometric U-series dating of speleothems from Tangshan Cave, combined with ecological and paleoclimatic evidence, indicates that Nanjing Man, a typical Homo erectus morphologically correlated with Peking Man at Zhoukoudian, should be at least 580 k.y. old, or more likely lived during the glacial oxygen isotope stage 16 (˜620 ka). Such an age estimate, which is ˜270 ka older than previous electron spin resonance and alpha-counting U-series dates, has significant implications for the evolution of Asian H. erectus. Dentine and enamel samples from the coexisting fossil layer yield significantly younger apparent ages, that of the enamel sample being only less than one-fourth of the minimum age of Nanjing Man. This suggests that U uptake history is far more complex than existing models can handle. As a result, great care must be taken in the interpretation of electron spin resonance and U-series dates of fossil teeth.

  10. Early hominin speciation at the Plio/Pleistocene transition.

    Science.gov (United States)

    Cameron, D W

    2003-01-01

    Over the last half-decade or so, there has been an explosion in the recognition of hominin genera and species. We now have the late Miocene genera Orrorin and Sahelanthropus, the mid Pliocene genus Kenyanthropus, three new Pliocene species of Australopithecus (A. anamensis, A. garhi and A. bahrelghazali) and a sub species of Ardipithecus (Ar. r. kadabba) to contend with. Excepting also the more traditional species allocated to Paranthropus, Australopithecus and early Homo we are approaching around 15 species over 5 million years (excluding hominin evolution over the last one million years). Can such a large number of hominin species be justified? An examination of extant hominid (Gorilla gorilla, Pan troglodytes, and Pan paniscus) anatomical variability indicates that the range of fossil hominin variability supports the recognition of this large number of fossil species. It is also shown that not all hominins are directly related to the emergence of early Homo and as such have become extinct. Indeed the traditional australopithecine species 'A'. anamensis, 'A'. afarensis and 'A'. garhi are considered here to belong to a distinct genus Praeanthropus. They are also argued not be hominins, but rather an as yet undefined hominid group from which the more derived hominins evolved. The first hominin is represented by A. africanus or a hominin very much like it. The Paranthropus clade is defined by a derived heterochronic condition of peramorphosis, associated with sequential progenesis (contraction of successive growth stages) in brain and dental development, but a mixture of peramorphic and paedomorphic features in its craniofacial anatomy. Conversely, Kenyanthropus and Homo both share a pattern of peramorphosis, associated with sequential hypermorphosis (prolongation of successive growth stages) in brain development, and paedomorphosis processes in cranial, facial and dental development. This suggests, that these two clades share an important synapomorphy not

  11. Pliocene hominin biogeography and ecology.

    Science.gov (United States)

    Macho, Gabriele A

    2015-10-01

    Australopithecus bahrelghazali, its origin and palaeobiology are not well understood. Reported from only one location some several thousand kilometres away from East African Pliocene hominin sites, it appears to have predominantly fed on C4 sources. Yet, it lacks the morphological adaptations of other primate C4 consumers like Paranthropus boisei and Theropithecus oswaldi. Furthermore, although considered to belong to Australopithecus afarensis by most researchers, A. bahrelghazali appears to differ from the former in a key aspect of its morphology: enamel thickness. To assess the phylogeny and palaeobiology of A. bahrelghazali, I first evaluate the dietary adaptations and energetics of A. bahrelghazali using empirical data of the feeding ecology of extant baboons, Papio cynocephalus. Information published on A. bahrelghazali morphology and habitat preference is used to select C4 foods with the appropriate mechanical properties and availability within the environment to create the models. By altering the feeding time on various food categories, I then test whether A. bahrelghazali could have subsisted on a C4 diet, thus accounting for the δ(13)C composition of its dental tissue. The effects of body mass on the volume of food consumed are taken into account. The outcomes of these simulations indicate that A. bahrelghazali could have subsisted on a diet of predominantly sedges, albeit with limitations. At higher energy requirements, i.e., above 3.5 times the BMR, it would be difficult for a medium-sized primate to obtain sufficient energy from a sedge-based diet. This is apparently due to constraints on foraging/feeding time, not because of the nutritional value of sedges per se. These results are discussed against the backdrop of A. bahrelghazali biogeography, palaeoenvironment, and phylogeny. The combined evidence makes it plausible to suggest that Northern Chad may have been a refugium for migrating mammals, including hominins, and throws new light on the deep

  12. Shark-Cetacean trophic interaction, Duinefontein, Koeberg, (5 Ma, South Africa

    Directory of Open Access Journals (Sweden)

    Romala Govender

    2015-11-01

    Full Text Available This study forms part of a larger project to reconstruct the Mio-Pliocene marine palaeoenvironment along South Africa’s west coast. It documents the shark–cetacean trophic interaction during the Zanclean (5 Ma at Duinefontein (Koeberg. The damage described on the fragmentary cetacean bones was compared with similar damage observed on fossils from Langebaanweg, a Mio-Pliocene site on the west coast of South Africa, and data present in the literature. This comparison showed that the damage was the result of shark bites. The state of preservation makes it difficult to determine if the shark bite marks were the cause of death or as a result of scavenging. The presence of the bite marks on the bone would, however, indicate some degree of skeletonisation. Bite marks on some cranial fragments would suggest that the cetacean’s body was in an inverted position typical of a floating carcass. The preservation of the material suggests that the bones were exposed to wave action resulting in their fragmentation as well as abrasion, polishing and rolling. It also suggests that the cetacean skeletons were exposed for a long time prior to burial. The morphology of the bites suggests that the damage was inflicted by sharks with serrated and unserrated teeth. Shark teeth collected from the deposit include megalodon (Carcharodon megalodon, white (Carcharodon carcharias as well as mako (Isurus sp. and Cosmopolitodus hastalis sharks, making these sharks the most likely predators/scavengers.

  13. Correlation of Plio Pleistocene Tephra in Ethiopian and Kenyan rift basins: Temporal calibration of geological features and hominid fossil records

    Science.gov (United States)

    WoldeGabriel, Giday; Hart, William K.; Katoh, Shigehiro; Beyene, Yonas; Suwa, Gen

    2005-10-01

    The 200-m-thick fossiliferous Konso Formation and overlying terrace deposits, which crop out at the end of the southern sector of the Main Ethiopian Rift (MER), contain more than 30 distal tephra layers. Local and regional tephra correlations of more than 20 tephra units were established using major and trace element data of discrete and purified bulk glass samples within the Konso study area. Eleven correlative marker tuffs were recognized in stratigraphic sections of both the Konso Formation and the Omo-Turkana Basin sediments in southern Ethiopia and northern Kenya. The Turoha, Hope, Ivory, Bright White, and Boleshe Tuffs in the Konso Formation, and the Upper White Tuff in the overlying terrace deposits are securely correlated with the KBS, Akait, Lokapetamoi, Chari, Lower Nariokotome, and Silbo Tuffs of the Omo-Turkana Basin, using least mobile major elements (CaO, Fe 2O 3*, and TiO 2) and geochronology. Preliminary correlations are also suggested between the Konso Formation distal tephra and proximal units of the Quaternary caldera-forming silicic centers in the central sector of the MER. The strongly peralkaline tuffs of the Konso Formation are compositionally similar to proximal eruptions mostly located along the Quaternary axial rift zone of the southern, central, and northern sectors of the MER. The tephra correlation provides information about the temporal and spatial features of the volcanic and tectonic processes recorded in the evolving basins. Thickness and sedimentation rate were determined for both the Konso Formation and the Omo-Turkana Basin sections, measured between the Turoha (=KBS; 1.91 ± 0.03 Ma) and the Bright White (=Chari; 1.40 ± 0.02 Ma) Tuffs. Although the lithostratigraphic sequence at the Konso study area is younger, sedimentation rate within the Konso Formation was comparable to that of the Koobi Fora Formation, higher in the Nachukui Formation, and lower in the Shungura Formation. Local and regional differences in thickness and sedimentation rates within the Plio-Pleistocene deposits of the Konso, Shungura, Nachukui, and Koobi Fora Formations may be attributed to erosion associated with increased topographic gradients maintained by continued subsidence mostly along axial fault zones of basins and uplift along the margins of the broadly rifted zone of the Omo-Turkana Basin and the southern sector of the MER.

  14. Sociální rozumění u lidí a ostatních hominidů

    Czech Academy of Sciences Publication Activity Database

    Urban, Petr

    2014-01-01

    Roč. 69, č. 7 (2014), s. 591-603 ISSN 0046-385X R&D Projects: GA ČR GPP401/12/P544 Institutional support: RVO:67985955 Keywords : Social cognition * Anthropological difference * Theory of mind * Interactive turn * Joint attention * Joint intentionality * Apes Subject RIV: AA - Philosophy ; Religion

  15. The role of docosahexaenoic and the marine food web as determinants of evolution and hominid brain development: the challenge for human sustainability.

    Science.gov (United States)

    Crawford, Michael A; Broadhurst, C Leigh

    2012-01-01

    Life originated on this planet about 3 billion years ago. For the first 2.5 billion years of life there was ample opportunity for DNA modification. Yet there is no evidence of significant change in life forms during that time. It was not until about 600 million years ago, when the oxygen tension rose to a point where air-breathing life forms became thermodynamically possible, that a major change can be abruptly seen in the fossil record. The sudden appearance of the 32 phyla in the Cambrian fossil record was also associated with the appearance of intracellular detail not seen in previous life forms. That detail was provided by cell membranes made with lipids (membrane fats) as structural essentials. Lipids thus played a major, as yet unrecognised, role as determinants in evolution. The compartmentalisation of intracellular, specialist functions as in the nucleus, mitochondria, reticulo-endothelial system and plasma membrane led to cellular specialisation and then speciation. Thus, not only oxygen but also the marine lipids were drivers in the Cambrian explosion. Docosahexaenoic acid (DHA) (all-cis-docosa-4,7,10,13,16,19-hexaenoic acid, C22:6ω3 or C22:6, n-3, DHA) is a major feature of marine lipids. It requires six oxygen atoms to insert its six double bonds, so it would not have been abundant before oxidative metabolism became plentiful. DHA provided the membrane backbone for the emergence of new photoreceptors that converted photons into electricity, laying the foundation for the evolution of other signalling systems, the nervous system and the brain. Hence, the ω3 DHA from the marine food web must have played a critical role in human evolution. There is also clear evidence from molecular biology that DHA is a determinant of neuronal migration, neurogenesis and the expression of several genes involved in brain growth and function. That same process was essential to the ultimate cerebral expansion in human evolution. There is now incontrovertible support of this hypothesis from fossil evidence of human evolution taking advantage of the marine food web. Lipids are still modifying the present evolutionary phase of our species; their signature is evident in the changing panorama of non-communicable diseases. The most worrying change in disease pattern is the sharp rise in brain disorders, which, in the European Union, has overtaken the cost of all other burdens of ill health at €386 billion for the 25 member states at 2004 prices. In 2007, the UK cost was estimated at £77 billion and confirmed in 2010 at £105 billion - greater than heart disease and cancer combined. The rise in mental ill health is now being globalised. The solution to the rising vascular disorders in the last century and now brain disorders in this century lies in a radical reappraisal of the food system, which last century was focussed on protein and calories, with little attention paid to the requirements of the brain - the very organ that was the determinant of human evolution. With the marine fish catch having plateaued 20 years ago and its sustainability now under threat, a critical aspect of this revision is the development of marine agriculture from estuarine, coastal and oceanic resources. Such action is likely to play a key role in future health and intelligence.

  16. Variations in size, shape and asymmetries of the third frontal convolution in hominids: paleoneurological implications for hominin evolution and the origin of language.

    Science.gov (United States)

    Balzeau, Antoine; Gilissen, Emmanuel; Holloway, Ralph L; Prima, Sylvain; Grimaud-Hervé, Dominique

    2014-11-01

    The study of brain structural asymmetries as anatomical substrates of functional asymmetries in extant humans, great apes, and fossil hominins is of major importance in understanding the structural basis of modern human cognition. We propose methods to quantify the variation in size, shape and bilateral asymmetries of the third frontal convolution (or posterior inferior frontal gyrus) among recent modern humans, bonobos and chimpanzees, and fossil hominins using actual and virtual endocasts. These methodological improvements are necessary to extend previous qualitative studies of these features. We demonstrate both an absolute and relative bilateral increase in the size of the third frontal convolution in width and length between Pan species, as well as in hominins. We also observed a global bilateral increase in the size of the third frontal convolution across all species during hominin evolution, but also non-allometric intra-group variations independent of brain size within the fossil samples. Finally, our results show that the commonly accepted leftward asymmetry of Broca's cap is biased by qualitative observation of individual specimens. The trend during hominin evolution seems to be a reduction in size on the left compared with the right side, and also a clearer definition of the area. The third frontal convolution considered as a whole projects more laterally and antero-posteriorly in the right hemisphere. As a result, the left 'Broca's cap' looks more globular and better defined. Our results also suggest that the pattern of brain asymmetries is similar between Pan paniscus and hominins, leaving the gradient of the degree of asymmetry as the only relevant structural parameter. As the anatomical substrate related to brain asymmetry has been present since the appearance of the hominin lineage, it is not possible to prove a direct relationship between the extent of variations in the size, shape, and asymmetries of the third frontal convolution and the origin of language in hominins. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Hominid visitation of the Moravian Karst during the Middle-Upper Paleolithic transition: New results from Pod Hradem Cave (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Nejman, L.; Wood, R.; Wright, D.; Lisá, Lenka; Nerudová, Z.; Neruda, P.; Přichystal, A.; Svoboda, Jiří

    2017-01-01

    Roč. 108, JUL 2017 (2017), s. 131-146 ISSN 0047-2484 Institutional support: RVO:67985831 ; RVO:68081758 Keywords : Middle-Upper Paleolithic transition * chronology * AMH * Neanderthal * Pod Hradem Cave * Moravia Subject RIV: AC - Archeology, Anthropology, Ethnology; AC - Archeology, Anthropology, Ethnology (ARUB-Q) OBOR OECD: Environmental sciences (social aspects to be 5.7); Archaeology (ARUB-Q) Impact factor: 3.932, year: 2016

  18. Geology and preliminary dating of the hominid-bearing sedimentary fill of the Sima de los Huesos Chamber, Cueva Mayor of the Sierra de Atapuerca, Burgos, Spain.

    Science.gov (United States)

    Bischoff, J L; Fitzpatrick, J A; León, L; Arsuagà, J L; Falgueres, C; Bahain, J J; Bullen, T

    1997-01-01

    Sediments of the Sima de los Huesos vary greatly over distances of a few meters. This is typical of interior cave facies, and caused by cycles of cut and fill. Mud breccias containing human bones, grading upwards to mud containing bear bones, fill an irregular surface cut into basal marks and sands. The lack of Bedding and the chaotic abundance of fragile speleothem clasts in the fossiliferous muds suggests that the deposit was originally a subterranean pond facies, and that after emplacement of the human remains, underwent vigorous post-depositional rotation and collapse and brecciation, caused by underlying bedrock dissolution and undermining. The fossiliferous deposits are capped by flowstone and guano-bearing muds which lack large-mammal fossils. U-series and radiocarbon dating indicates the capping flowstones formed from about 68 ka to about 25 ka. U-series analyses of speleothem clasts among the human fossils indicate that all are at, or close to, isotopic equilibrium (> 350 ka). The distribution of U-series dates for 25 bear bones (154 +/- 66 ka) and for 16 human bones (148 +/- 34 ka) is similar and rather broad. Because the human bones seem to be stratigraphically older than chose of the bears, the results would indicate that most of the bones have been accumulating uranium irregularly with time. Electron spin resonance (ESR) analyses of six selected bear bones indicates dates of 189 +/- 28 ka, for which each is cordant with their corresponding U-series date (181 +/- 41 ka). Combined ESR and U-series dates for these samples yielded 200 +/- 4 ka. Such agreement is highly suggestive that uranium uptake in these bones was close to the early-uptake (EU) model, and the dates are essentially correct. Another three selected samples yielded combined ESR U-series dates of 320 +/- 4 ka with a modeled intermediate-mode of uranium uptake. The dating results, therefore, seem to provide a firm minimum age of about 200 ka for the human entry: and suggestive evidence of entry before 320 ka.

  19. Late Miocene/Pliocene Ostracod Biostratigraphy from South Carpathian Foredeep, Romania (Badislava-Topolog Area)

    Science.gov (United States)

    Floroiu, Alina; Stoica, Marius; Vasiliev, Iuliana; Krijgsman, Wout

    2016-04-01

    The Paratethys epicontinental sea has been an essential paleogeographic feature defining the Eurasian interior since Oligocene. By the end of the Miocene, ongoing tectonic activity in the region determined severe restrictions of the connection of the large former Paratethys sea resulting in the formation of several smaller subbasins: the Pannonian basin, the Dacian basin, the Black Sea and the Caspian Sea. In the western part of the Dacian Basin, the thick and continuous Mio-Pliocene sedimentary successions of the Getic Depression of Romania provide an exceptional opportunity to study the paleoecological changes in the Eastern Paratethys during the time when the Mediterranean and Black Sea experienced important sea level changes related to the Messinian Salinity Crisis. These sedimentary successions were the basis of high-resolution magnetobiostratigraphic studies that allow a detailed correlation to the Geological Time Scale. Here, we present the main characteristics of the ostracod assemblages of the Late Miocene/Pliocene sedimentary succession from Badislava-Topolog section covering the Eastern Paratethys regional Maeotian and Pontian, stages that are, at moment, under ongoing formal stratigraphic definition process. The Mio-Pliocene is exposed in the central part of the Getic Depression, especially Topolog-Arges area, where it riches up to 500 m in thickness being incorporated into a large monocline structure with 15o-20o plungeto the south. The Upper Maeotian deposits from the area have developed mainly in fluviatile-deltaic facies with frequent continental intercalations. The ostracod assemblage is represented by rare fresh water ostracods of Candona, Pseudocandona and Ilyocypris genera, capable to populate unstable environments like flood-plains, lakes and rivers with temporary existence. The scarce Maeotian ostracod fauna from this marginal section differs essentially from the more diversified one of the same age recorded in areas that evolved in basinal

  20. Foramen magnum position in bipedal mammals.

    Science.gov (United States)

    Russo, Gabrielle A; Kirk, E Christopher

    2013-11-01

    The anterior position of the human foramen magnum is often explained as an adaptation for maintaining balance of the head atop the cervical vertebral column during bipedalism and the assumption of orthograde trunk postures. Accordingly, the relative placement of the foramen magnum on the basicranium has been used to infer bipedal locomotion and hominin status for a number of Mio-Pliocene fossil taxa. Nonetheless, previous studies have struggled to validate the functional link between foramen magnum position and bipedal locomotion. Here, we test the hypothesis that an anteriorly positioned foramen magnum is related to bipedalism through a comparison of basicranial anatomy between bipeds and quadrupeds from three mammalian clades: marsupials, rodents and primates. Additionally, we examine whether strepsirrhine primates that habitually assume orthograde trunk postures exhibit more anteriorly positioned foramina magna compared with non-orthograde strepsirrhines. Our comparative data reveal that bipedal marsupials and rodents have foramina magna that are more anteriorly located than those of quadrupedal close relatives. The foramen magnum is also situated more anteriorly in orthograde strepsirrhines than in pronograde or antipronograde strepsirrhines. Among the primates sampled, humans exhibit the most anteriorly positioned foramina magna. The results of this analysis support the utility of foramen magnum position as an indicator of bipedal locomotion in fossil hominins. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Late cenozoic magmatism in the South Patagonian batholith: SHRIMP U-Pb zircon age evidence

    International Nuclear Information System (INIS)

    Fanning, C.M; Herve, F; Pankhurst, R.J; Thomson, S; Faundez, V

    2001-01-01

    The North Patagonian Batholith (NPB) has a zonal age pattern which includes a well defined belt of Miocene and Mio-Pliocene plutons in its central portion (Pankhurst et al., 1999) which are spatially, and probably genetically related to the Liquine-Ofqui Fault Zone. Previous geochronological studies in the Southern Patagonian Batholith (SPB), as summarized by Bruce et al. (1991), have yielded 9 late Cenozoic K-Ar or Ar-Ar ages out of a total of 116 age determinations. None of these young ages correspond to U-Pb determinations on zircons, and some of the young ages correspond to satellite plutons east of the SPB proper, such as the Torres del Paine intrusion. In this paper we present the first late Cenozoic SHRIMP U-Pb zircon ages in the area of the SPB. The morphology of the analysed zircon crystals is described and leads to some inferences on the methodology and on the geological interpretation of the obtained ages (au)

  2. Late Pleistocene acceleration of deformation across the northern Tianshan piedmont (China) evidenced from the morpho-tectonic evolution of the Dushanzi anticline

    Science.gov (United States)

    Charreau, Julien; Saint-Carlier, Dimitri; Lavé, Jérôme; Dominguez, Stéphane; Blard, Pierre-Henri; Avouac, Jean-Philippe; Brown, Nathan D.; Malatesta, Luca Claude; Wang, Shengli; Rhodes, Edward J.

    2018-04-01

    We document the temporal evolution of deformation in the northern Tianshan piedmont where the deformation is partitioned across several thrusts and folds. We focus on the Dushanzi anticline, where abandoned terraces and growth strata allow us to constrain the history of folding since the Miocene. Based on subsurface seismic imaging, structural measurements and morphological analysis, we show that this anticline is associated with two decollement levels. We use kink band migration in growth strata dated by paleomagnetism to constrain the shortening from the Mio-Pliocene to the Holocene. Our results show that the Dushanzi anticline has been active since at least 8 Ma and that the fold grew at a steady shortening rate of 0.6 ± 0.1 mm/yr from 8 to 1.5 Ma with possible variations from 2.5 to 1.5 Ma. Then it accelerated rapidly to a rate of 4.3 ± 1.0 mm/yr over at least the last 100 ka. These results, together with similar temporal shortening evolutions across other structures, suggest that the deformation rate across the eastern Tianshan piedmont increased relatively recently. This may reflect either a redistribution of the deformation from the internal structures toward the borders or a general acceleration of the deformation across the entire range.

  3. Thallium in mineral resources extracted in Poland

    Directory of Open Access Journals (Sweden)

    Bojakowska I.

    2013-04-01

    Full Text Available Thallium concentrations in primary mineral commodities extracted in Poland and processed in high temperatures were determined by ICP-MS method. Samples of hard and brown coal, copper-silver and zinclead ores, argillaceous and calcareous rocks of different genesis and age were analyzed. The highest thallium concentrations occur in the zinc-lead ores, the average content being of 52.1 mg/kg. The copper ores contain in average 1.4 mg/kg of thallium. Hard coals from the Upper Silesian Coal Basin display higher thallium content than those exploited in the Lublin Coal Basin. Brown coals from Turow deposit distinguish by much higher values, 0.7 mg/kg Tl, than those from huge Bełchatów and smaller Konin-Turek region deposits. Average thallium concentrations in clays used for ceramic materials are lower than 1 mg/kg, except of Mio-Pliocene Slowiany deposit. The average content of thallium in the studied limestone and dolomite raw materials for cement, lime, and metallurgical flux, and refractories is very low in comparison to the average amounts in the world carbonate rocks.

  4. Hydrogeochemical processes in the Plio-Quaternary Remila aquifer (Khenchela, Algeria)

    Science.gov (United States)

    Aouidane, Laiche; Belhamra, Mohamed

    2017-06-01

    The Remila Plain is a synclinal structure in northeast Algeria, situated within a semi-arid climate zone and composed of Mio-Pliocene-Quaternary deposits. Within the syncline, the Plio-Quaternary aquifer is the main source of drinking water for cattle and for agricultural irrigation water. This work aims to investigate the origin of groundwater mineralization and to identify the primary hydrogeochemical processes controlling groundwater evolution in the Remila aquifer. A total of 86 water samples from boreholes were analyzed for major, minor and stable isotopes (18O, 2H) over three seasons: first during low water levels in 2013, second during high water levels in 2014 and third for stable isotopes during low water levels in 2015. The analysis showed that the aquifer is controlled by five principal geochemical processes: (I) the dissolution of evaporite rocks, (II) cation exchange and reverse exchange reactions, (III) congruent dissolution of carbonates (calcite, dolomite) coupled with the dissolution of gypsum and calcite precipitation, (IV) sulfate reduction under anaerobic conditions, and (V) saltwater intrusion in the northeastern Sabkha plains. The 18O and deuterium concentrations in groundwater are very low, indicating that the aquifer is recharged by evaporated rainfall originating from the north slope of the Aurès Mountains which confirms that the aquifer is recharged in the southern part of the plain.

  5. The rise of ocean giants: maximum body size in Cenozoic marine mammals as an indicator for productivity in the Pacific and Atlantic Oceans.

    Science.gov (United States)

    Pyenson, Nicholas D; Vermeij, Geerat J

    2016-07-01

    Large consumers have ecological influence disproportionate to their abundance, although this influence in food webs depends directly on productivity. Evolutionary patterns at geologic timescales inform expectations about the relationship between consumers and productivity, but it is very difficult to track productivity through time with direct, quantitative measures. Based on previous work that used the maximum body size of Cenozoic marine invertebrate assemblages as a proxy for benthic productivity, we investigated how the maximum body size of Cenozoic marine mammals, in two feeding guilds, evolved over comparable temporal and geographical scales. First, maximal size in marine herbivores remains mostly stable and occupied by two different groups (desmostylians and sirenians) over separate timeframes in the North Pacific Ocean, while sirenians exclusively dominated this ecological mode in the North Atlantic. Second, mysticete whales, which are the largest Cenozoic consumers in the filter-feeding guild, remained in the same size range until a Mio-Pliocene onset of cetacean gigantism. Both vertebrate guilds achieved very large size only recently, suggesting that different trophic mechanisms promoting gigantism in the oceans have operated in the Cenozoic than in previous eras. © 2016 The Authors.

  6. A synthesis: Late Cenozoic stress field distribution at northeastern corner of the Eastern Mediterranean, SE Turkey

    Science.gov (United States)

    Over, Semir; Ozden, Suha; Unlugenc, Ulvi Can; Yılmaz, Huseyin

    2004-01-01

    Fault kinematic analysis and inversion of focal mechanisms of shallow earthquakes reveal significant evolution of the regional stress regime in the northeastern most corner of the Eastern Mediterranean region since the Mio-Pliocene to the present time. This study was carried out in the interaction area between the Arabian/African plates and the Anatolian block. The evolution of stress regimes consists of a change from older transpression to younger transtension. Both strike-slip stress regimes having a NNW- to northwest-trending σHmax ( σ1) and ENE- to northeast-trending σHmin ( σ3) axes induce a sinistral component of displacement on the major intra-continental Karatas-Osmaniye and Misis-Ceyhan faults elongated with the northeast-trending Misis Range between Adana and Osmaniye provinces (sub-area i) and by a NNE-trending plate boundary Amanos fault running along Amanos Range between Antakya and Kahramanmaras provinces (sub-area ii). The inversion results show that the transtensional stress regime is dominantly strike-slip to extension, with an ENE- to northeast-trending σHmin ( σ3) axis for sub-areas ( i) and ( ii), respectively. The inversions of earthquake focal mechanisms indicate that the transtensional stress regime is still active in the whole study area since probably recent Quaternary time. To cite this article: S. Over et al., C. R. Geoscience 336 (2004).

  7. Molecular data and ecological niche modelling reveal a highly dynamic evolutionary history of the East Asian Tertiary relict Cercidiphyllum (Cercidiphyllaceae).

    Science.gov (United States)

    Qi, Xin-Shuai; Chen, Chen; Comes, Hans Peter; Sakaguchi, Shota; Liu, Yi-Hui; Tanaka, Nobuyuki; Sakio, Hitoshi; Qiu, Ying-Xiong

    2012-10-01

    East Asia's temperate deciduous forests served as sanctuary for Tertiary relict trees, but their ages and response to past climate change remain largely unknown. To address this issue, we elucidated the evolutionary and population demographic history of Cercdiphyllum, comprising species in China/Japan (Cercdiphyllum japonicum) and central Japan (Cercdiphyllum magnificum). Fifty-three populations were genotyped using chloroplast and ribosomal DNA sequences and microsatellite loci to assess molecular structure and diversity in relation to past (Last Glacial Maximum) and present distributions based on ecological niche modelling. Late Tertiary climate cooling was reflected in a relatively recent speciation event, dated at the Mio-/Pliocene boundary. During glacials, the warm-temperate C. japonicum experienced massive habitat losses in some areas (north-central China/north Japan) but increases in others (southwest/-east China, East China Sea landbridge, south Japan). In China, the Sichuan Basin and/or the middle-Yangtze were source areas of postglacial northward recolonization; in Japan, this may have been facilitated through introgressive hybridization with the cool-temperate C. magnificum. Our findings challenge the notion of relative evolutionary and demographic stability of Tertiary relict trees, and may serve as a guideline for assessing the impact of Neogene climate change on the evolution and distribution of East Asian temperate plants. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  8. Molecules and fossils reveal punctuated diversification in Caribbean "faviid" corals.

    Science.gov (United States)

    Schwartz, Sonja A; Budd, Ann F; Carlon, David B

    2012-07-25

    Even with well-known sampling biases, the fossil record is key to understanding macro-evolutionary patterns. During the Miocene to Pleistocene in the Caribbean Sea, the fossil record of scleractinian corals shows a remarkable period of rapid diversification followed by massive extinction. Here we combine a time-calibrated molecular phylogeny based on three nuclear introns with an updated fossil stratigraphy to examine patterns of radiation and extinction in Caribbean corals within the traditional family Faviidae. Concatenated phylogenetic analysis showed most species of Caribbean faviids were monophyletic, with the exception of two Manicina species. The time-calibrated tree revealed the stem group originated around the closure of the Tethys Sea (17.0 Ma), while the genus Manicina diversified during the Late Miocene (8.20 Ma), when increased sedimentation and productivity may have favored free-living, heterotrophic species. Reef and shallow water specialists, represented by Diploria and Favia, originate at the beginning of the Pliocene (5 - 6 Ma) as the Isthmus of Panama shoaled and regional productivity declined. Later origination of the stem group than predicted from the fossil record corroborates the hypothesis of morphological convergence in Diploria and Favia genera. Our data support the rapid evolution of morphological and life-history traits among faviid corals that can be linked to Mio-Pliocene environmental changes.

  9. Autogenic Versus Allogenic Controls on the Evolution of a Coupled Fluvial Megafan-Mountainous Catchment System: Insight from Numerical Modelling

    Science.gov (United States)

    Mouchene, M.; van der Beek, P.; Carretier, S.; Mouthereau, F.

    2017-12-01

    Alluvial megafans are sensitive recorders of landscape evolution, controlled by both autogenic processes and allogenic forcing, and they are influenced by the coupled dynamics of the fan with its mountainous catchment. The Mio-Pliocene Lannemezan megafan in the northern Pyrenean foreland (SW France) was abandoned by its mountainous feeder stream during the Quaternary and subsequently incised. The flight of alluvial terraces abandoned along the stream network may suggest a climatic control on the incision. We use a landscape evolution numerical model (CIDRE) to explore the relative roles of autogenic processes and external forcing in the building, abandonment and incision of a foreland megafan, and we compare the results with the inferred evolution of the Lannemezan megafan. Autogenic processes are sufficient to explain the building of a megafan and the long-term entrenchment of its feeding river on time and space scales that match the Lannemezan setting. Climate, through temporal variations in precipitation rate, may have played a role in the episodic pattern of incision on a shorter timescale. In contrast, base-level changes, tectonic activity in the mountain range or tilting of the foreland through flexural isostatic rebound do not appear to have played a role in the abandonment of the megafan.

  10. Molecules and fossils reveal punctuated diversification in Caribbean “faviid” corals

    Directory of Open Access Journals (Sweden)

    Schwartz Sonja A

    2012-07-01

    Full Text Available Abstract Background Even with well-known sampling biases, the fossil record is key to understanding macro-evolutionary patterns. During the Miocene to Pleistocene in the Caribbean Sea, the fossil record of scleractinian corals shows a remarkable period of rapid diversification followed by massive extinction. Here we combine a time-calibrated molecular phylogeny based on three nuclear introns with an updated fossil stratigraphy to examine patterns of radiation and extinction in Caribbean corals within the traditional family Faviidae. Results Concatenated phylogenetic analysis showed most species of Caribbean faviids were monophyletic, with the exception of two Manicina species. The time-calibrated tree revealed the stem group originated around the closure of the Tethys Sea (17.0 Ma, while the genus Manicina diversified during the Late Miocene (8.20 Ma, when increased sedimentation and productivity may have favored free-living, heterotrophic species. Reef and shallow water specialists, represented by Diploria and Favia, originate at the beginning of the Pliocene (5 – 6 Ma as the Isthmus of Panama shoaled and regional productivity declined. Conclusions Later origination of the stem group than predicted from the fossil record corroborates the hypothesis of morphological convergence in Diploria and Favia genera. Our data support the rapid evolution of morphological and life-history traits among faviid corals that can be linked to Mio-Pliocene environmental changes.

  11. Impact of climate changes during the last 5 million years on groundwater in basement aquifers.

    Science.gov (United States)

    Aquilina, Luc; Vergnaud-Ayraud, Virginie; Les Landes, Antoine Armandine; Pauwels, Hélène; Davy, Philippe; Pételet-Giraud, Emmanuelle; Labasque, Thierry; Roques, Clément; Chatton, Eliot; Bour, Olivier; Ben Maamar, Sarah; Dufresne, Alexis; Khaska, Mahmoud; Le Gal La Salle, Corinne; Barbecot, Florent

    2015-09-22

    Climate change is thought to have major effects on groundwater resources. There is however a limited knowledge of the impacts of past climate changes such as warm or glacial periods on groundwater although marine or glacial fluids may have circulated in basements during these periods. Geochemical investigations of groundwater at shallow depth (80-400 m) in the Armorican basement (western France) revealed three major phases of evolution: (1) Mio-Pliocene transgressions led to marine water introduction in the whole rock porosity through density and then diffusion processes, (2) intensive and rapid recharge after the glacial maximum down to several hundred meters depths, (3) a present-day regime of groundwater circulation limited to shallow depth. This work identifies important constraints regarding the mechanisms responsible for both marine and glacial fluid migrations and their preservation within a basement. It defines the first clear time scales of these processes and thus provides a unique case for understanding the effects of climate changes on hydrogeology in basements. It reveals that glacial water is supplied in significant amounts to deep aquifers even in permafrosted zones. It also emphasizes the vulnerability of modern groundwater hydrosystems to climate change as groundwater active aquifers is restricted to shallow depths.

  12. Site characterization and site response in Port-au-Prince, Haiti

    Science.gov (United States)

    Hough, Susan E.; Yong, Alan K.; Altidor, Jean Robert; Anglade, Dieuseul; Given, Douglas D.; Mildor, Saint-Louis

    2011-01-01

    Waveform analysis of aftershocks of the Mw7.0 Haiti earthquake of 12 January 2010 reveals amplification of ground motions at sites within the Cul de Sac valley in which Port-au-Prince is situated. Relative to ground motions recorded at a hard-rock reference site, peak acceleration values are amplified by a factor of approximately 1.8 at sites on low-lying Mio-Pliocene deposits in central Port-au-Prince and by a factor of approximately 2.5–3 on a steep foothill ridge in the southern Port-au-Prince metropolitan region. The observed amplitude, predominant periods, variability, and polarization of amplification are consistent with predicted topographic amplification by a steep, narrow ridge. A swath of unusually high damage in this region corresponds with the extent of the ridge where high weak-motion amplifications are observed. We use ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) imagery to map local geomorphology, including characterization of both near-surface and of small-scale topographic structures that correspond to zones of inferred amplification.

  13. Description of a new species of Sparassocynus (Marsupialia: Didelphoidea: Sparassocynidae) from the late Miocene of Jujuy (Argentina) and taxonomic review of Sparassocynus heterotopicus from the Pliocene of Bolivia.

    Science.gov (United States)

    Abello, María Alejandra; De Los Reyes, Martín; Candela, Adriana Magdalena; Pujos, Francois; Voglino, Damián; Quispe, Bernardino Mamani

    2015-03-24

    A new species of sparassocynid marsupial, Sparassocynus maimarai n. sp. from the late Miocene of Maimará Formation (Jujuy Province, Argentina) is described from a left mandibular fragment with a complete p2-m4 series. It differs from the remaining species of the genus S. bahiai (Montehermosan-late Miocene/early Pliocene-of Buenos Aires Province, Argentina) and S. derivatus (Chapadmalalan and Marplatan-Pliocene of Buenos Aires Province) by its smaller size, the relatively longer m1 with respect to the m4, the presence of a lingual cingulum extended between para- and metaconid on the m1-3, and its more robust entoconids. As part of this study the taxonomic status of Sparassocynus heterotopicus (Montehermosan, Umala, Bolivia; Pliocene) was reviewed concluding that this taxon should be referred to as 'Sparassocynus' heterotopicus and considered a Didelphoidea of uncertain affinities. Sparassocynus maimarai n. sp. is the oldest records of the genus, adding new information to evaluate the origins and early diversification of sparassocynids. Sparassocynus maimarai n. sp. was recovered with precise stratigraphic control, highlighting its potential biostratigraphic significance to the temporal correlations between Maimará Formation and other Mio-Pliocene stratigraphic units from the northwestern Argentina.

  14. Refining upon the climatic background of the Early Pleistocene hominid settlement in western Europe: Barranco León and Fuente Nueva-3 (Guadix-Baza Basin, SE Spain)

    Science.gov (United States)

    Blain, Hugues-Alexandre; Lozano-Fernández, Iván; Agustí, Jordi; Bailon, Salvador; Menéndez Granda, Leticia; Espígares Ortiz, Maria Patrocinio; Ros-Montoya, Sergios; Jiménez Arenas, Juan Manuel; Toro-Moyano, Isidro; Martínez-Navarro, Bienvenido; Sala, Robert

    2016-07-01

    The Early Pleistocene sites of Barranco León and Fuente Nueva-3 (Guadix-Baza Basin, SE Spain) have yielded thousands of Mode 1 or Oldowan lithic artifacts (both sites) and one tooth (in layer D, formerly 5 of Barranco León), today considered to be some of the earliest evidence of humans in western Europe at ca. 1.2-1.5 Ma. Previous quantitative paleoclimatic reconstructions based on herpetile assemblages indicated that, during the formation of these two sites, the mean annual temperature and mean annual precipitation were higher than they are now in the southeastern Iberian Peninsula, with lower continentality. Here, we propose new climatic reconstructions where the mean monthly temperature and precipitation and the difference between the four driest months and the four rainiest months are estimated. Climatograms are built in order to specify the distribution and variation of temperature and precipitation during the year, and the Aridity Indices of Gaussen, Lautensach-Mayer, Dantin-Revenga and De Martonne are used to characterize ombroclimatic differences. According to these new climatic parameters, rainfall distribution through the year shows considerably higher precipitation in every season except summer and early autumn, which remain drier and thus consistent with a Mediterranean climate pattern. No change is observed in the duration of the aridity period, which remains four months long. However, the value of the Aridity Index of De Martonne is higher than 20 (subhumid climate) in Barranco León and Fuente Nueva-3, whereas today it is lower than 20 (semi-arid climate), suggesting major changes in the ombroclimatic type. These results yield a more precise scenario for the paleoclimatic conditions that prevailed during the late Early Pleistocene in the Guadix-Baza Basin and permit us to contrast the ages obtained from numerical dating and biochronology. The very warm and humid climate reconstructed for both Barranco León and Fuente Nueva-3 suggests that, in accordance with the numerical dating, these two sites are contemporaneous with the particularly warm interglacial peaks of Marine Isotope Stages 43-49 (i.e. between 1.35 and 1.47 Ma). The similarity between reconstructed climates, the high overlap between their estimated precipitation and between the difference of the driest from the rainiest season suggest that these sites may correspond to the same part of a climatic glacial/interglacial cycle, but because the evolutionary degree of the rodent Mimomys savini shows a slightly more derived state for Fuente Nueva-3 than for Barranco León (i.e a short chronological difference between the two sites), they may correspond to two consecutive warm interglacial peaks.

  15. A multidisciplinary analysis to constrain exhumation and recent erosion history of the Tethyan Himalaya, based on apatite (U-Th-Sm)/He and cosmogenic nuclides dates from Central Nepal (Takkhola graben and the Mustang granite)

    Science.gov (United States)

    Rosenkranz, Ruben; Sahragard Sohi, Mohammad; Spiegel, Cornelia

    2015-04-01

    The exhumation of the Himalayan arc has been studied intensively throughout the last decades. For the Tethyan Himalaya, however, the youngest exhumation history is still unclear, mostly because of the lack of a significant apatite content in most Tethyan sediments (Crouzet et al. 2007). For this study we are using apatite (U-Th-Sm)/He thermochronology and cosmogenic nuclides for investigating exhumation and denudation of the Tethyan Himalaya back through time. Apatite (U-Th-Sm)/He thermochronology is sensitive to temperatures of ~40 to 85°C and thus to movements within the upper ~1.5 to 3 km of the earth's crust. During a recent field campaign, we sampled the Mustang granite, that intrudes the Tethyan marine sediments and the Takkhola-Graben. The graben can be seen as an inusual southern part of the normal faulting system affecting the whole Tibetan Plateau (Colchen, 1999). The timing of the activation of these faulting is still highly debated. The syntectonics filling of the Takkhola-Mustag graben consists of Mio-Pliocene fluvio-lacustrine deposits (Garzione et al. 2003). These were described as containing significant amounts of apatite, derived from the past erosion of the Mustang granitic body (Adhikari and Wagreich, 2011). Being only up to 1km thick, a post depositional thermal resetting of the apatite (U-Th-Sm)/He system is unlikely, so that the (U-Th-Sm)/He dates of the sediments are expected to have retained their information regarding source area exhumation. We took several sand samples from the Kali Gandaki River draining the present-day exposure of the Mustang granite. Furthermore, we sampled different stratigraphic levels of the Mio-Pliocene sedimentary rocks, i.e., from the Tetang and Takkahola formation deposited between 11 and 7 Ma. This sampling approach will not only provide information about the youngest denudation history of the Mustang granite /Tethyan Himalaya, but will also reveal insights into its past denudation and changes of denudation

  16. Fulltext PDF

    Indian Academy of Sciences (India)

    to Raymond Dart, a professor of anatomy at the University of. Witwatersrand in Johannesburg. Dart analysed the skull, and in his article, published in Nature in 1925, described the specimen. Box 1. Hominid Encephalization. The steady increase in brain size in the hominid lineage - from 420 cc in Autralopithecus afarensis ...

  17. Probing atomic scale transformation of fossil dental enamel using Fourier transform infrared and nuclear magnetic resonance spectroscopy: a case study from the Tugen Hills (Rift Gregory, Kenya).

    Science.gov (United States)

    Yi, Haohao; Balan, Etienne; Gervais, Christel; Ségalen, Loïc; Roche, Damien; Person, Alain; Fayon, Franck; Morin, Guillaume; Babonneau, Florence

    2014-09-01

    A series of fossil tooth enamel samples was investigated by Fourier transform infrared (FTIR) spectroscopy, (13)C and (19)F magic-angle spinning nuclear magnetic resonance (MAS NMR) and scanning electron microscopy (SEM). Tooth remains were collected in Mio-Pliocene deposits of the Tugen Hills in Kenya. Significant transformations were observed in fossil enamel as a function of increasing fluorine content (up to 2.8wt.%). FTIR spectroscopy revealed a shift of the ν1 PO4 stretching band to higher frequency. The ν2 CO3 vibrational band showed a decrease in the intensity of the primary B-type carbonate signal, which was replaced by a specific band at 864cm(-1). This last band was ascribed to a specific carbonate environment in which the carbonate group is closely associated to a fluoride ion. The occurrence of this carbonate defect was consistently attested by the observation of two different fluoride signals in the (19)F NMR spectra. One main signal, at ∼-100ppm, is related to structural F ions in the apatite channel and the other, at -88ppm, corresponds to the composite defect. These spectroscopic observations can be understood as resulting from the mixture of two phases: biogenic hydroxylapatite (bioapatite) and secondary fluorapatite. SEM observations of the most altered sample confirmed the extensive replacement of the bioapatite by fluorapatite, resulting from the dissolution of the primary bioapatite followed by the precipitation of carbonate-fluorapatite. The ν2 CO3 IR bands can be efficiently used to monitor the extent of this type of bioapatite transformation during fossilization. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  18. Timing and sources of neogene and quaternary volcanism in South-Central Guatemala

    Science.gov (United States)

    Reynolds, James H.

    1987-08-01

    Five new and six existing radiometric age dates place constraints on the timing of volcanic episodes in a 1400-km 2 area east of Guatemala City. The source of the voluminous Miocene rhyolitic welded tuffs was the newly discovered Santa Rosa de Lima caldera, in the northern part of the area, not fissure eruptions as was previously believed. Resurgence during the Pliocene included the eruption of more silicic tuffs, followed by post-collapse volcanism around the perimeter. Volcanism in the southern part of the area occurred along the Neogene volcanic front. The sources for these Late Miocene and Pliocene andesitic lavas were not fissure eruptions, as was once believed, but were four large volcanic centers, Cerro Pinula, Ixhuatán, Teanzul, and Cerro La Gabia. The Santa Rosa de Lima caldera structure deflects the Jalpatagua Fault forming tensional fractures along which eruptions in the Quaternary Cuilapa-Barbarena cinder cone field took place. Pleistocene ash flows were erupted from Ixhuatán and Tecuamburro volcanoes in the southern part of the area. Tephras from Ayarza, Amatitlán, and Atitlán blanket the northern and central portions. Present-day activity is restricted to hot springs around the northern and eastern base of Tecuamburro volcano. Based on the work in this area it is proposed that rocks of the Miocene Chalatenango Formation throughout northern Central America were erupted from calderas behind the Neogene volcanic front. Rocks of the Mio-Pliocene Bálsamo Formation in Guatemala and El Salvador were erupted from discrete volcanic centers along the Neogene volcanic front. Pliocene rocks of the Cuscatlán Formation probably represent post-collapse volcanism around earlier caldera structures.

  19. Vicariance and Its Impact on the Molecular Ecology of a Chinese Ranid Frog Species-Complex (Odorrana schmackeri, Ranidae.

    Directory of Open Access Journals (Sweden)

    Yongmin Li

    Full Text Available Paleogeological events and Pleistocene climatic fluctuations have had profound influences on the genetic patterns and phylogeographic structure of species in southern China. In this study, we investigated the population genetic structure and Phylogeography of the Odorrana schmackeri species complex, mountain stream-dwelling odorous frogs, endemic to southern China. We obtained mitochondrial sequences (1,151bp of the complete ND2 gene and two flanking tRNAs of 511 individuals from 25 sites for phylogeographic analyses. Phylogenetic reconstruction revealed seven divergent evolutionary lineages, with mean pairwise (K2P sequence distances from 7.8% to 21.1%, except for a closer ND2 distance (3.4%. The complex geological history of southern China drove matrilineal divergence in the O. schmackeri species complex into highly structured geographical units. The first divergence between lineage A+B and other lineages (C-G had likely been influenced by the uplift of coastal mountains of Southeast China during the Mio-Pliocene period. The subsequent divergences between the lineages C-G may have followed the formation of the Three Gorges and the intensification of the East Asian summer monsoon during the late Pliocene and early Pleistocene. Demographic analyses indicated that major lineages A and C have been experienced recent population expansion (c. 0.045-0.245 Ma from multiple refugia prior to the Last Glacial Maximum (LGM. Molecular analysis suggest that these seven lineages may represent seven different species, three described species and four cryptic species and should at least be separated into seven management units corresponding to these seven geographic lineages for conservation.

  20. Arsenic concentrations in soils and sediments of the southern Pampean Plain, within Claromecó River Basin (Argentina)

    Science.gov (United States)

    Sosa, N. N.; Datta, S.; Zarate, M.

    2015-12-01

    The Pampean plain is an extensive flatland covering ~1000000 km2 of central and northern Argentina. The region, dominated by Neogene and quaternary volcanoclastic loess and loess-like deposits, shows one of the highest groundwater As concentrations of the world which cause serious problems to human health. The oxidising and high pH conditions of the Pampean groundwater leads to the dissolution of volcanic glass and Fe oxy-hydroxides and the release of As to water. Variation of As content related to lithogenic factors is evident from our study in Claromecó River Basin (Southern Pampean plain): the Mio-Pliocene fluvial facies (MPFF) show low As content (2.6mg/kg) compared to the Late Pleistocene fluvial facies (11.6mg/kg; LPFF). Furthermore, the pedogenic calcrete and the paleosols developed in fluvial facies present significantly different As content: 3.9 mg/Kg in MPFF pedogenic calcrete and 16.5 mg/Kg in LPFF paleosols. Modern soils show the highest As content, especially in the illuvial horizons (23.3 mg/Kg) controlled by grain size and clay mineralogy constituents. Preliminary results demonstrate a sedimentological control embarking differences in As concentrations. These differences are probably attributed to a major hydraulic gradient during the MPFF, which is reflected in grain size and in fluvial structures, which probably was followed by washed out sediments. A geomorphological control was observed through an increase of As concentrations from the interfluves (MPFF) to the valleys (LPFF) as well as from the upper to the lower basin zone within the LPFF. Pedogenic calcrete and paleosols developed in MPFF and LPFF respectively reflect the different geomorphological conditions showing high As content in LPFF paleosols (attributed to Fe oxy-hydroxides). This study relates mineralogy and sedimentological environment to groundwater, surface water from wetlands to understand the hydrochemical processes in controlling As within the Claromecó basin.

  1. Late Cenozoic stress distribution along the Misis Range in the Anatolian, Arabian, and African plate intersection region, SE Turkey

    Science.gov (United States)

    Over, Semir; Ozden, Suha; Can Unlugenc, Ulvi

    2004-06-01

    This study defines the Mio-Pliocene to present-day stress regime acting at the northeastern Mediterranean along the SE border of the Neogene Adana basin along the Misis Range. The inversion of earthquake focal mechanisms shows that the present-day state of stress is dominantly a transtension, combined the strike-slip and extension with a consistent ENE (N83°E) trending σHmin (σ3) axis. The inversion slip vectors measured on fault planes and chronologies between striations indicate a consistent strike-slip stress regime that varied from transpressional initially to transtensional during Pleistocene time, with the latter continuing into recent times as indicated by earthquake focal mechanism inversions. Both states have consistent NNW (N15°W) trending, compatible with NNW Arabian drift direction, and ENE (N75°E) trending σHmax (σ1) and σHmin (σ3) axes, respectively, but have significantly different mean arithmetic stress ratio (Rm) values: Rm = 0.75 indicating transpression for the old regional stress regime and Rm of 0.20 denoting transtensional for the younger regional stress regime. The crosscutting of striations confirms also the change within the strike-slip stress regime. Both stress regimes induce sinistral displacement along the major strike-slip fault systems, i.e., East Anatolian Fault, Karatas-Osmaniye Fault. The temporal stress regime change probably occurred during Quaternary time and resulted from coeval influence of the superimposed forces owing to subduction processes in the southwest along the Cyprus arc, continental collision in the east, and westward escape of the Anatolian Block in the north and west.

  2. Inherited weaknesses control deformation in the flat slab region of Central Argentina

    Science.gov (United States)

    Stevens, A.; Carrapa, B.; Larrovere, M.; Aciar, R. H.

    2015-12-01

    The Sierras Pampeanas region of west-central Argentina has long been considered a geologic type-area for flat-slab induced thick-skinned deformation. Frictional coupling between the horizontal subducting plate and South American lithosphere from ~12 Ma to the present provides an obvious causal mechanism for the basement block uplifts that characterize this region. New low temperature thermochronometry data show basement rocks from the central Sierras Pampeanas (~ longitude 66 ̊ W) including Sierras Cadena de Paiman, Velasco and Mazan retain a cooling history of Paleozoic - Mesozoic tectonics events. Results from this study indicate that less than 2 km of basement has been exhumed since at least the Mesozoic. These trends recorded by both apatite fission track (AFT) and apatite helium (AHe) thermochronometry suggest that recent Mio-Pliocene thick-skinned deformation associated with flat-slab subduction follow inherited zones of weakness from Paleozoic terrane sutures and shear zones and Mesozoic rifting. If a Cenozoic foreland basin exisited in this region, its thickness was minimal and was controlled by paleotopography. Pre-Cenozoic cooling ages in these ranges that now reach as high as 4 km imply significant exhumation of basement rocks before the advent of flat slab subduction in the mid-late Miocene. It also suggests that thick-skinned deformation associated with flat slab subduction may at least be facilitated by inherited crustal-scale weaknesses. At the most, pre-existing zones of weakness may be required in regions of thick-skinned deformation. Although flat-slab subduction plays an important role in the exhumation of the Sierras Pampeanas, it is likely not the sole mechanism responsible for thick-skinned deformation in this region. This insight sheds light on the interpretation of modern and ancient regions of thick-skinned deformation in Cordilleran systems.

  3. Vicariance and Its Impact on the Molecular Ecology of a Chinese Ranid Frog Species-Complex (Odorrana schmackeri, Ranidae).

    Science.gov (United States)

    Li, Yongmin; Wu, Xiaoyou; Zhang, Huabin; Yan, Peng; Xue, Hui; Wu, Xiaobing

    2015-01-01

    Paleogeological events and Pleistocene climatic fluctuations have had profound influences on the genetic patterns and phylogeographic structure of species in southern China. In this study, we investigated the population genetic structure and Phylogeography of the Odorrana schmackeri species complex, mountain stream-dwelling odorous frogs, endemic to southern China. We obtained mitochondrial sequences (1,151bp) of the complete ND2 gene and two flanking tRNAs of 511 individuals from 25 sites for phylogeographic analyses. Phylogenetic reconstruction revealed seven divergent evolutionary lineages, with mean pairwise (K2P) sequence distances from 7.8% to 21.1%, except for a closer ND2 distance (3.4%). The complex geological history of southern China drove matrilineal divergence in the O. schmackeri species complex into highly structured geographical units. The first divergence between lineage A+B and other lineages (C-G) had likely been influenced by the uplift of coastal mountains of Southeast China during the Mio-Pliocene period. The subsequent divergences between the lineages C-G may have followed the formation of the Three Gorges and the intensification of the East Asian summer monsoon during the late Pliocene and early Pleistocene. Demographic analyses indicated that major lineages A and C have been experienced recent population expansion (c. 0.045-0.245 Ma) from multiple refugia prior to the Last Glacial Maximum (LGM). Molecular analysis suggest that these seven lineages may represent seven different species, three described species and four cryptic species and should at least be separated into seven management units corresponding to these seven geographic lineages for conservation.

  4. East African Cenozoic vegetation history.

    Science.gov (United States)

    Linder, Hans Peter

    2017-11-01

    The modern vegetation of East Africa is a complex mosaic of rainforest patches; small islands of tropic-alpine vegetation; extensive savannas, ranging from almost pure grassland to wooded savannas; thickets; and montane grassland and forest. Here I trace the evolution of these vegetation types through the Cenozoic. Paleogene East Africa was most likely geomorphologically subdued and, as the few Eocene fossil sites suggest, a woodland in a seasonal climate. Woodland rather than rainforest may well have been the regional vegetation. Mountain building started with the Oligocene trap lava flows in Ethiopia, on which rainforest developed, with little evidence of grass and none of montane forests. The uplift of the East African Plateau took place during the middle Miocene. Fossil sites indicate the presence of rainforest, montane forest and thicket, and wooded grassland, often in close juxtaposition, from 17 to 10 Ma. By 10 Ma, marine deposits indicate extensive grassland in the region and isotope analysis indicates that this was a C 3 grassland. In the later Miocene rifting, first of the western Albertine Rift and then of the eastern Gregory Rift, added to the complexity of the environment. The building of the high strato-volcanos during the later Mio-Pliocene added environments suitable for tropic-alpine vegetation. During this time, the C 3 grassland was replaced by C 4 savannas, although overall the extent of grassland was reduced from the mid-Miocene high to the current low level. Lake-level fluctuations during the Quaternary indicate substantial variation in rainfall, presumably as a result of movements in the intertropical convergence zone and the Congo air boundary, but the impact of these fluctuations on the vegetation is still speculative. I argue that, overall, there was an increase in the complexity of East African vegetation complexity during the Neogene, largely as a result of orogeny. The impact of Quaternary climatic fluctuation is still poorly understood

  5. Plio-quaternary deposits in the Eastern Rharb (Nw Morocco): Electrosequential characterization

    Science.gov (United States)

    Al Mazini, Imane; Mridekh, Abdelaziz; Kili, Malika; El Mansouri, Bouâbid; El Bouhaddioui, Mohamed; Magrane, Bouchaib

    2018-02-01

    The Rharb basin, of which our study area is part, is located at the western extremity of the south Rif corridor. It corresponds to a subsiding zone that appeared in the Upper Miocene, between two major structural domains: the Rif to the north and east and the Meseta domain to the south. The eastern part of this basin is characterized by a Plio-Quaternary continental fill. Its geographical position and its structural and paleo-environmental contexts are reflected by a great facies heterogeneity. This work aims to image the subsurface structure and to characterize the distribution mode of Plio-Quaternary deposits of the eastern Rharb. The use of a database consisting of geo-electrical cross sections, hydrogeological drilling and wireline logging integrated in a Geographic Information System (GIS) allowed us to establish a new three-dimensional model of the top of the Mio-Pliocene substratum, new geo-electrical cross sections, as well as the isopach maps of lower, intermediate, upper and superficial geo-electric interval. This approach allowed us to characterize the Plio-Quaternary deposits of the study area and to highlight the effects of the tectonic regime and the relative sea level fluctuations on the sequential organization of these deposits. Our new model shows the development of prograding, aggrading and retrograding parasequences denoting the existence of autogenic mechanisms in the organization of plio-quaternary deposits of the eastern part of the Rharb basin. Therefore, it opens new perspectives for the exploration of water resources and monitoring their quality throughout the basin.

  6. Depósitos epitermales de baja sulfuración ricos en sulfuros de metales base, distrito aurífero La Carolina, San Luis, Argentina

    Directory of Open Access Journals (Sweden)

    Gallard-Esquivel María Cecilia

    2011-12-01

    Full Text Available Low-sulfidation epithermal base-metal sulfide-rich deposits, La Carolina gold-bearing district,San Luis, Argentina. La Carolina gold-bearing district is located at the western end of the Metallogenetic Belt of San Luis, which is spatially and genetically related to the mesosilicic volcanism of mio-pliocene age. The volcanic arc experienced an eastward migration, due to the flattening of the Nazca plate in the segment 27°-33°S, known as the Pampean flat-slab. At La Carolina, the volcanic activity occurred between 8.2 and 6.3 Ma. It encompasses lavas and pyroclastics of andesitic, dacitic, latitic and trachytic composition. The mesosilicic magmas belong to normal to high-k calc-alkaline and shoshonitic suites. Structural analysis shows that previous structures have strongly controlled the emplacement of volcanic rocks and related mineral deposits at La Carolina allowing to define a pullapart.In this gold-bearing district there are eigth small mineralized prospects. The mineralogy consists of pyrite, arsenic rich pyrite, galena, sphalerite, marcasite, melnikovite, chalcopyrite, pyrrhotite, arsenopyrite, tennantitetetrahedrite, digenite, covellite, bornite, pyrargiryte, hessite, silvanite, pearceite, argirodite, gold, silver, greigite, boulangerite, jamesonite and electrum. The gangue consists of quartz, calcite, chalcedony and minor adularia.The hydrothermal alteration is widespread and comprise phyllic and argillic mineral assemblages characterized by sericite, illite, interstratified I/S, and silicic; propylitic alteration is also present as an outer halo. Fluid inclusions studies show that the formation temperatures range between 230º to 330º C. Boiling and mixing with meteoric water led to mineral precipitation. Based on the mineralogy, textures, hydrothermal alteration, formation temperatures,fluid chemistry and prospective geochemistry the mineralizations have been classified as low-sulfidation epithermal base-metal sulfide-rich deposits.

  7. Palaeoanthropology, chronology, and archeology of the Matjes River Rock Shelter

    Energy Technology Data Exchange (ETDEWEB)

    Protsch, R.; Oberholzer, J.J.

    1975-11-01

    The Matjes River Rock Shelter is one of fourteen sites with Upper Pleistocene fossil hominids in Subsaharan Africa which was absolutely and relatively dated. It is one of the few sites where not only one isolated fossil hominid was dated, but hominids and fauna throughout several stratigraphic levels. Absolute dates, using a new collagen-extraction-method, were compared to radiocarbon dates run by other laboratories several years ago on shell and charcoal. This collagen method supplied a crosscheck on the accuracy of dates on organic materials commonly used for radiocarbon dating and absolute dates on bones. The stratigraphically lowest hominid (M.R.I.) could thus be absolutely and directly dated for the first time. From a chronological point of view, M.R.I. can be fitted into a sequence including such fossil hominids as Border Cave, Florisbad, Fish Hoek, Boskop, Bushman Rock Shelter, and M.R.I. The latter is a fairly recent representative of Homosapiens afer.

  8. Baboon Feeding Ecology Informs the Dietary Niche of Paranthropus boisei

    OpenAIRE

    Macho, Gabriele A.

    2014-01-01

    Hominins are generally considered eclectic omnivores like baboons, but recent isotope studies call into question the generalist status of some hominins. Paranthropus boisei and Australopithecus bahrelghazali derived 75%-80% of their tissues' δ(13)C from C4 sources, i.e. mainly low-quality foods like grasses and sedges. Here I consider the energetics of P. boisei and the nutritional value of C4 foods, taking into account scaling issues between the volume of food consumed and body mass, and P. ...

  9. Isotopic evidence for an early shift to C₄ resources by Pliocene hominins in Chad.

    Science.gov (United States)

    Lee-Thorp, Julia; Likius, Andossa; Mackaye, Hassane T; Vignaud, Patrick; Sponheimer, Matt; Brunet, Michel

    2012-12-11

    Foods derived from C(4) plants were important in the dietary ecology of early Pleistocene hominins in southern and eastern Africa, but the origins and geographic variability of this relationship remain unknown. Carbon isotope data show that Australopithecus bahrelghazali individuals from Koro Toro in Chad are significantly enriched in (13)C, indicating a dependence on C(4) resources. As these sites are over 3 million years in age, the results extend the pattern of C(4) dependence seen in Paranthropus boisei in East Africa by more than 1.5 million years. The Koro Toro hominin fossils were found in argillaceous sandstone levels along with abundant grazing and aquatic faunal elements that, in combination, indicate the presence of open to wooded grasslands and stream channels associated with a greatly enlarged Lake Chad. In such an environment, the most abundant C(4) plant resources available to A. bahrelghazali were grasses and sedges, neither of which is usually considered as standard great ape fare. The results suggest an early and fundamental shift in hominin dietary ecology that facilitated the exploitation of new habitats.

  10. Isotopic evidence for an early shift to C4 resources by Pliocene hominins in Chad

    Science.gov (United States)

    Lee-Thorp, Julia; Likius, Andossa; Mackaye, Hassane T.; Vignaud, Patrick; Sponheimer, Matt; Brunet, Michel

    2012-01-01

    Foods derived from C4 plants were important in the dietary ecology of early Pleistocene hominins in southern and eastern Africa, but the origins and geographic variability of this relationship remain unknown. Carbon isotope data show that Australopithecus bahrelghazali individuals from Koro Toro in Chad are significantly enriched in 13C, indicating a dependence on C4 resources. As these sites are over 3 million years in age, the results extend the pattern of C4 dependence seen in Paranthropus boisei in East Africa by more than 1.5 million years. The Koro Toro hominin fossils were found in argillaceous sandstone levels along with abundant grazing and aquatic faunal elements that, in combination, indicate the presence of open to wooded grasslands and stream channels associated with a greatly enlarged Lake Chad. In such an environment, the most abundant C4 plant resources available to A. bahrelghazali were grasses and sedges, neither of which is usually considered as standard great ape fare. The results suggest an early and fundamental shift in hominin dietary ecology that facilitated the exploitation of new habitats. PMID:23150583

  11. Osteometrical and functional analysis and evolution of autopodia in the genus Homo

    Czech Academy of Sciences Publication Activity Database

    Nývltová Fišáková, Miriam

    2003-01-01

    Roč. 49, - (2003), s. 107-109 ISSN 1210-048X Institutional research plan: CEZ:AV0Z8001916 Keywords : Pleistocene * Fossil Hominids * Palaeolithic Subject RIV: AC - Archeology, Anthropology, Ethnology

  12. Clavicles, scapulae and humeri from the Sima de los Huesos site (Sierra de Atapuerca, Spain).

    Science.gov (United States)

    Carretero, J M; Arsuaga, J L; Lorenzo, C

    1997-01-01

    The scapulae, clavicles and humeri recovered from the Sima de los Huesos (SH) site between 1976 and 1994 are studied. All elements are briefly described anatomically with metrics and compared with other fossil hominids in order to establish the morphological pattern of the SH hominids. A minimum of 13 individuals are represented by the humeri in the SH sample. Almost all of them can be classified as adolescents and young adults. The morphology of the SH hominid shoulder girdle and humeri indicates that much of the shoulder morphology recognized in the later true Neandertal was present in Europe long before they appeared. Thus, this morphological pattern is not exclusive to Neandertals alone. The SH clavicles, scapulae and humeri share with the Neandertals many traits usually considered to be Neandertal specializations. The comparative analysis of the SH evidence suggests that most of the SH and Neandertal shared traits are either primitive features within the genus Homo or even for all hominids, or display high variability within different hominid samples. These traits must be used with caution, or not used at all, in phylogenetic analysis. There are, however, traits that to date have only been detected in the SH hominids and the Neanderials, which could be exclusive to the European phyletic lineage (clade) of Homo.

  13. Burial and thermal history simulation of the Abu Rudeis-Sidri oil field, Gulf of Suez-Egypt: A 1D basin modeling study

    Science.gov (United States)

    Awadalla, Ahmed; Hegab, Omar A.; Ahmed, Mohammed A.; Hassan, Saad

    2018-02-01

    An integrated 1D model on seven wells has been performed to simulate the multi-tectonic phases and multiple thermal regimes in the Abu Rudeis-Sidri oilfield. Concordance between measured and calculated present-day temperatures is achieved with present-day heat flows in the range of 42-55 mW/m2. Reconstruction of the thermal and burial histories provides information on the paleotemperature profiles, the timing of thermal activation as well as the effect of the Oligo-Miocene rifting phases and its associated magmatic activity. The burial histories show the pre-rift subsidence was progressive but modest, whereas the syn-rift was more rapid (contemporaneous with the main rifting phases and basin formation). Finally, the early post-rift thermal subsidence was slow to moderate in contrast to the late post-rift thermal subsidence which was moderate to rapid. The simulated paleo heat flow illustrates a steady state for the pre-rift phase and non-steady state (transient) for syn-rift and postrift phases. Three geothermal regimes are recognized, each of which is associated with a specific geological domain. 1) A lower geothermal regime reflects the impact of stable tectonics (pre-rift). 2) The higher temperature distribution reflects the syn-rift high depositional rate as well as the impact of stretching and thinning (rifting phases) of the lithosphere. 3) A local higher geothermal pulse owing to the magmatic activity during the Oligo-Miocene time (ARM-1 and Sidri-7 wells). Paleoheat flow values of 100mW/m2 (Oligo-Miocene rifting phase) increased to 120mW/m2 (Miocene rifting phase) and lesser magnitude of 80mW/m2 (Mio- Pliocene reactivation phase) have been specified. These affected the thermal regime and temperature distribution by causing perturbations in subsurface temperatures. A decline in the background value of 60mW/m2 owing to conductive cooling has been assigned. The blanketing effect caused by low thermal conductivity of the basin-fill sediments has been simulated

  14. Water-borne radon and hydrogeochemical based uranium exploration in Rajamundry sandstone, W. Godavari district, Andhra Pradesh

    International Nuclear Information System (INIS)

    Jeyagopal, A.V.; Rajaraman, H.S.; Som, Anjan

    2010-01-01

    The lithology and sedimentary structures of the Rajamundry Formation of the Mio-Pliocene age covering an area of 1100 sq.km. indicate that it may be a typical valley fill sediment. It is about 600 m thick comprising sandstone and clay with lignite as the main lithounits. It is continental in onshore and marine in the offshore and is in contact with Gondwana sediments and Rajamundry traps. Tertiary sandstones are important hosts for uranium mineralisation. The reducing gas (Methane or other volatile hydrocarbon) moving to uraniferous oxidising water has precipitated uranium in the sediments in South Texas and Northwest Colorado, USA: (a) along faults, (b) above petroliferous aquifers, (c) vertically above hydrocarbon accumulations and (d) oil-water interface at hydrocarbon accumulations i.e., at the points of introduction of reducent into oxidising ground waters. In this context, Rajamundry sandstone lying above the natural gas and petroleum bearing Krishna Godavari basin with faults is an important geological setting for uranium mineralisation. The exploration strategies of hydrogeochemical survey and water-borne Radon (Rn) surveys were selected in this soil-covered area. Hydrogeochemical survey carried out in the Rajamundry sandstone has brought out four hydro-uranium anomalous zones with water samples (10-45ppb) falling around Kadiyadda, Madhavaram, Erramalla and Chinna Malapalle areas of West Godavari district, Andhra Pradesh. The zones vary from 9 to 24 sq km area. Water-borne Radon was utilized as a tool for exploration of uranium in this soil covered terrain. Rn contours cluster around two zones around Kadiyadda and SW of Gollagudem wherein the Rn value is >60 counts/50 sec/500 ml. These Rn anomalies fall within the above mentioned hydrouranium anomalous zones. Gamma-ray logging of private bore wells has recorded relatively higher radioactivity in Kommugudem, which also falls in the high hydrouranium - high waterborne radon zone. These data and

  15. Post-Eocene climate change across continental Australia and the diversification of Australasian spiny trapdoor spiders (Idiopidae: Arbanitinae).

    Science.gov (United States)

    Rix, Michael G; Cooper, Steven J B; Meusemann, Karen; Klopfstein, Seraina; Harrison, Sophie E; Harvey, Mark S; Austin, Andrew D

    2017-04-01

    -plugging in transitional arid zone taxa have evolved twice independently in Western Australia, while in Misgolas and Cataxia, burrow door-building behaviours have likely been independently lost at least three times in the eastern Australian mesic zone. We also show that the presence of idiopids in New Zealand (Cantuaria) is likely to be the result of recent dispersal from Australia, rather than ancient continental vicariance. By providing the first comprehensive, continental synopsis of arid zone biogeography in an Australian arachnid lineage, we show that the diversification of arbanitine Idiopidae was intimately associated with climate shifts during the Neogene, resulting in multiple Mio-Pliocene radiations. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. A multi-locus inference of the evolutionary diversification of extant flamingos (Phoenicopteridae).

    Science.gov (United States)

    Torres, Chris R; Ogawa, Lisa M; Gillingham, Mark A F; Ferrari, Brittney; van Tuinen, Marcel

    2014-03-01

    Modern flamingos (Phoenicopteridae) occupy a highly specialized ecology unique among birds and represent a potentially powerful model system for informing the mechanisms by which a lineage of birds adapts and radiates. However, despite a rich fossil record and well-studied feeding morphology, molecular investigations of the evolutionary progression among modern flamingos have been limited. Here, using three mitochondrial (mtDNA) markers, we present the first DNA sequence-based study of population genetic variation in the widely distributed Chilean Flamingo and, using two mtDNA and 10 nuclear (nDNA) markers, recover the species tree and divergence time estimates for the six extant species of flamingos. Phylogenetic analyses include likelihood and Bayesian frameworks and account for potential gene tree discordance. Analyses of divergence times are fossil calibrated at the divergence of Mirandornithes (flamingos + grebes) and the divergence of crown grebes. mtDNA sequences confirmed the presence of a single metapopulation represented by two minimally varying mtDNA barcodes in Chilean flamingos. Likelihood and Bayesian methods recovered identical phylogenies with flamingos falling into shallow-keeled (comprising the Greater, American and Chilean Flamingos) and deep-keeled (comprising the Lesser, Andean and James's Flamingos) sub-clades. The initial divergence among flamingos occurred at or shortly after the Mio-Pliocene boundary (6-3 Ma) followed by quick consecutive divergences throughout the Plio-Pleistocene. There is significant incongruence between the ages recovered by the mtDNA and nDNA datasets, likely due to mutational saturation occurring in the mtDNA loci. The finding of a single metapopulation in the widespread Chilean Flamingo confirms similar findings in other widespread flamingo species. The robust species phylogeny is congruent with previous classifications of flamingos based on feeding morphology. Modern phoenicopterids likely originated in the New

  17. Zagros Geodynamics, From Subduction to Collision: The Fate of the Neotethys

    Science.gov (United States)

    Omrani, J.; Agard, P.; Jolivet, L.; Whitechurch, H.; Monié, P.

    2008-12-01

    The Zagros orogen preserves the record of three main periods/regimes in the convergence history of the Neotethys: (1) Long-lasting subduction processes and arc magmatism (>150-35 Ma). Trace and rare-earth element systematics on the upper plate Sanandaj-Sirjan and Urumieh-Dokhtar magmatic arcs show that they originated from similar, subduction-related mantle sources. The inward shift of arc magmatism (~300 km) from the former to the latter at the end of the Tertiary likely resulted from a change in kinematics and was predated by the formation of the Paleocene-Eocene intraoceanic arc of Kermanshah (earlier thought to represent a remnant of the Peri-Arabic obduction). Oceanic subduction proper ended by 35-30 Ma and was followed by collision. (2) A distinctive period of pertubation of subduction processes (115-85 Ma). A sharp rise of convergence velocities across the Neotethys at ~115 Ma was followed by two regional- scale (i.e., > 3000 km along strike), coeval (~100-80 Ma), short-lived major tectonic phenomena: - the transient exhumation of oceanic blueschists all along the Neotethyan subduction zone, which testifies to a change in plate-slab coupling, - the development of intra-oceanic subduction ultimately leading to the obduction of oceanic crust onto Arabia. (3) Collision and slab tear at depths (~25-0 Ma). Collision started before ~25-23 Ma (in Lorestan) and resulted in 70 km of shortening in the internal zones alone over the last 20-15 My. Calc-alkaline magmatism resumed in the Urumieh-Dokhtar magmatic arc after collision, mainly from the Mio-Pliocene onwards. In Central Zagros this syn-collision magmatism shows a distinctive adakitic trend attributable to the melting at depths of mafic material in response to localized slab breakoff (i.e. 200-300 km along strike), as further supported by tomography. The timing of this event is thus broadly coeval with slab-breakoff below southern Turkey and supports the view that slab tearing propagated in the Neotethyan slab

  18. Incomplete cryptic speciation between intertidal and subtidal morphs of Acrocnida brachiata (Echinodermata: Ophiuroidea) in the Northeast Atlantic.

    Science.gov (United States)

    Muths, D; Davoult, D; Gentil, F; Jollivet, D

    2006-10-01

    The brittle-star Acrocnida brachiata (Montagu) lives in sandy-bottom habitat of both intertidal and subtidal zones along the coasts of the northwestern Europe. An allozyme frequency-based survey (five enzyme loci) was combined with a mitochondrial (mt) COI haplotype analysis (598-bp sequences) on 17 populations to trace back past colonization pathways from the actual population structure of the species. Both genetic markers display a sharp genetic break between intertidal (clade I) and subtidal populations (clade S). This break corresponds to an allele frequency inversion at three enzyme loci (Hk, Pgm and Pgi) and a deep divergence of about 20% in mtCOI sequences between most of the intertidal populations and other samples. The geographic distribution of clade I seems to be more restricted than clade S as it is absent from the intertidal of the eastern English Channel and North Sea and may be replaced by clade S in south Brittany. Applying previously published rates of mutation, divergence between the two clades is estimated to pre-date 5 million years ago and may be due to allopatric speciation processes at the Mio-Pliocene transition. The occurrence of putative hybrids in a few localities, however, suggests incomplete cryptic speciation with secondary contact zones. The relative importance of colonization history vs. habitat specialization are discussed in the light of neutral evolution as tested from mtCOI gene sequences. While differential selection seems to have contributed little to the separation of the lineages, it may have played a role in the emergence of adaptive polymorphisms in the hybrid zone. Furthermore, congruent spatial patterns of differentiation were observed in both clades suggesting a recent increase in population size. These findings are in agreement with a recent expansion of the populations during or after the formation of the English Channel, from a southern refuge for the subtidal clade whereas the intertidal clade may have persisted

  19. Geographic variation in the African-Iberian ground beetle Rhabdotocarabus melancholicus (Coleoptera: Carabidae and its taxonomical and biogeographical implications

    Directory of Open Access Journals (Sweden)

    París, M.

    1995-12-01

    Full Text Available A study of morphological variation among populations from southern Spain and northwestern Africa of Rhabdotocarabus melancholicus (Fabricius, 1798 shows that there is statistical support for the recognition of three taxa: R. m. submeridionalis (Breuning, 1975 distributed over southeastern Spain, R. m. dehesicola n. ssp. from southwestern Spain and southern Portugal and R. m. melancholicus geographically restricted to northwestern Africa. This new arrangement changes previous biogeographic pictures for the genus, since R. m. melancholicus is not present in Europe and the range of variation observed within Iberian R. melancholicus is increased with new endemic taxa. We propose that the current differentiation among taxa is the result of successive vicariance events caused by dramatic paleogeographic changes which have occurred in the western Mediterranean region since the Mio-Pliocene boundary.Un estudio de la variación morfológica de poblaciones del sur de España y del noroeste de África de Rhabdotocarabus melancholicus (Fabricius, 1798 permite reconocer estadísticamente la existencia de dos taxa en las porciones meridionales de la Península Ibérica: R. m. submeridionalis (Breuning, 1975 distribuido por la región suroriental ibérica y R. m. dehesicola n. ssp. del suroeste de España y sur de Portugal; un tercer taxon, R. m. melancholicus, antes incluido en la fauna ibérica se considera ahora exclusivo del noroeste de África. Esta nueva estructura taxonómica cambia el cuadro biogeográfico previamente considerado para el género, ya que R. m. melancholicus no se encuentra en Europa, mientras que la diversidad taxonómica observada en Iberia se incrementa con dos táxones endémicos. Proponemos que la diferenciación observada es el producto de eventos vicariantes sucesivos resultado de los amplios cambios paleogeográficos producidos en la región mediterránea occidental desde el límite Mio-Pliocénico.

  20. Paleoanthropology and evolutionary theory.

    Science.gov (United States)

    Tattersall, Ian

    2012-01-01

    Paleoanthropologists of the first half of the twentieth century were little concerned either with evolutionary theory or with the technicalities and broader implications of zoological nomenclature. In consequence, the paleoanthropological literature of the period consisted largely of a series of descriptions accompanied by authoritative pronouncements, together with a huge excess of hominid genera and species. Given the intellectual flimsiness of the resulting paleoanthropological framework, it is hardly surprising that in 1950 the ornithologist Ernst Mayr met little resistance when he urged the new postwar generation of paleoanthropologists to accept not only the elegant reductionism of the Evolutionary Synthesis but a vast oversimplification of hominid phylogenetic history and nomenclature. Indeed, the impact of Mayr's onslaught was so great that even when developments in evolutionary biology during the last quarter of the century brought other paleontologists to the realization that much more has been involved in evolutionary histories than the simple action of natural selection within gradually transforming lineages, paleoanthropologists proved highly reluctant to follow. Even today, paleoanthropologists are struggling to reconcile an intuitive realization that the burgeoning hominid fossil record harbors a substantial diversity of species (bringing hominid evolutionary patterns into line with that of other successful mammalian families), with the desire to cram a huge variety of morphologies into an unrealistically minimalist systematic framework. As long as this theoretical ambivalence persists, our perception of events in hominid phylogeny will continue to be distorted.

  1. The beginnings of human palaeontology: prehistory, craniometry and the 'fossil human races'.

    Science.gov (United States)

    Goodrum, Matthew R

    2016-09-01

    Since the nineteenth century, hominid palaeontology has offered critical information about prehistoric humans and evidence for human evolution. Human fossils discovered at a time when there was growing agreement that humans existed during the Ice Age became especially significant but also controversial. This paper argues that the techniques used to study human fossils from the 1850s to the 1870s and the way that these specimens were interpreted owed much to the anthropological examination of Stone, Bronze, and Iron Age skeletons retrieved by archaeologists from prehistoric tombs throughout Europe. What emerged was the idea that a succession of distinct human races, which were identified using techniques such as craniometry, had occupied and migrated into Europe beginning in the Ice Age and continuing into the historic period. This marks a phase in the history of human palaeontology that gradually gave way to a science of palaeoanthropology that viewed hominid fossils more from the perspective of evolutionary theory and hominid phylogeny.

  2. Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge.

    Science.gov (United States)

    Kimura, Yuki

    2002-09-01

    The lithic analysis of the Bed I and II assemblages from Olduvai Gorge reveals both static and dynamic time trends in early hominids' technology from 1.8 to 1.2 m.y.a. The Bed I Oldowan (1.87-1.75 m.y.a.) is characterized by the least effort strategy in terms of raw material exploitation and tool production. The inclusion of new raw material, chert, for toolmaking in the following Developed Oldowan A (DOA, 1.65-1.53 m.y.a.) facilitated more distinctive and variable flaking strategies depending on the kind of raw materials. The unique characters of DOA are explainable by this raw material factor, rather than technological development of hominids. The disappearance of chert in the subsequent Developed Oldowan B and Acheulian (1.53-1.2 m.y.a.) necessitated a shift in tool production strategy more similar to that of Bed I Oldowan than DOA. However, the evidence suggests that Bed II hominids might have been more skillful toolmakers, intensive tool-users, and engaged in more active transport of stone tools than the Bed I predecessors. Koobi Fora hominids maintained a more static tool-using behavior than their Olduvai counterparts due mainly to a stable supply of raw materials. They differed from Olduvai hominids in terms of less battering of cores, consistent transport behavior, and few productions of side-struck flakes, indicating a regional variation of toolmaking and using practice. However, they shared with Olduvai hominids a temporal trend toward the production of larger flakes from larger cores after 1.6 m.y.a. Increased intake of animal resources and the expansion of ranging area of Homo ergaster would have led to the development of technological organization. Technological changes in the Oldowan industry are attested at Olduvai Gorge, Koobi Fora, and Sterkfontein, suggesting that it was a pan-African synchronous phenomenon, beginning at 1.5 m.y.a.

  3. Re-visiting the notion of Deep Incarnation in light of 1 Corinthians 15:28 and emergence theory

    Directory of Open Access Journals (Sweden)

    Wessel Bentley

    2016-08-01

    Full Text Available Niels Hendrik Gregersen’s ‘Deep Incarnation’ is opening up possibilities for engagementbetween science and theology. Recent discoveries, like that of Homo naledi, raise questions abouthow inclusive a Christian doctrine of Incarnation is. Is Jesus only God incarnate for Homo sapiensapiens, or is the incarnation inclusive of preceding hominid species as well? Does the incarnationstretch beyond the hominid line? This chapter engages Gregersen’s understanding of DeepIncarnation in light of 1 Corinthians 15:28 and emergence theory. It proposes that there is a directcorrelation between worldview and how we believe in the inclusive nature of divine incarnation.

  4. The geological, isotopic, botanical, invertebrate, and lower vertebrate contexts for aripithecus ramidus

    Energy Technology Data Exchange (ETDEWEB)

    Woldegabriel, Giday [Los Alamos National Laboratory; Ambrose, Stanley H [UNIV OF ILLINOIS; Barboni, Doris [CEREGE, FRANCE; Bonneffille, Raymond [CEREGE, FRANCE; Bremond, Laurent [MONTPELLIER, FRANCE; Currie, Brian [MIAMI UNIV, OXFORD, OHIO; Degusta, David [STANFORD UNIV.; Hart, William K [MIAMI UNIV, OXFORD, OHIO; Murray, Alison M [UNIV OF ALBERTA; Renne, Paul R [UC/BERKELEY; Jolly - Saad, M C [NANTERRE, FRANCE; Stewart, Kathlyn M [CANADA; White, Tim D [UC/BERKELEY

    2009-01-01

    Sediments containing Ardipithecus ramidus were deposited 4.4 million years ago on an alluvial floodplain in Ethiopia's western Afar rift. The Lower Aramis Member hominid-bearing unit, now exposed across a >9-kilometer structural arc, is sandwiched between two volcanic tuffs that have nearly identical {sup 40}Ar/{sup 39}Ar ages. Geological data presented here, along with floral, invertebrate, and vertebrate paleontological and taphonomic evidence associated with the hominids, suggest that they occupied a wooded biotope over the western three-fourths of the paleotransect. Phytoliths and oxygen and carbon stable isotopes of pedogenic carbonates provide evidence of humid cool woodlands with a grassy substrate.

  5. Modeling along-axis variations in fault architecture in the Main Ethiopian Rift: implications for Nubia-Somalia kinematics

    Science.gov (United States)

    Erbello, Asfaw; Corti, Giacomo; Sani, Federico; Kidane, Tesfaye

    2016-04-01

    The Main Ethiopian Rift (MER), at the northern termination of the East African Rift, is an ideal locale where to get insights into the long-term motion between Nubia and Somalia. The rift is indeed one of the few places along the plate boundary where the deformation is narrow: its evolution is thus strictly related to the kinematics of the two major plates, whereas south of the Turkana depression a two-plate model for the EARS is too simplistic as extension occurs both along the Western and Eastern branches and different microplates are present between the two major plates. Despite its importance, the kinematics responsible for development and evolution of the MER is still a matter of debate: indeed, whereas the Quaternary-present kinematics of rifting is rather well constrained, the plate kinematics driving the initial, Mio-Pliocene stages of extension is still not clear, and different hypothesis have been put forward, including: polyphase rifting, with a change in direction of extension from NW-SE extension to E-W extension; constant Miocene-recent NW-SE extension; constant Miocene-recent NE-SW extension; constant, post-11 Ma extension consistent with the GPS-derived kinematics (i.e., roughly E-W to ESE-WNW). To shed additional light on this controversy and to test these different hypothesis, in this contribution we use new crustal-scale analogue models to analyze the along-strike variations in fault architecture in the MER and their relations with the rift trend, plate motion and the resulting Miocene-recent kinematics of rifting. The extension direction is indeed one of the most important parameters controlling the architecture of continental rifts and the relative abundance and orientation of different fault sets that develop during oblique rifting is typically a function of the angle between the extension direction and the orthogonal to the rift trend (i.e., the obliquity angle). Since the trend of the MER varies along strike, and consequently it is

  6. Transgressive systems tract development and incised-valley fills within a quaternary estuary-shelf system: Virginia inner shelf, USA

    Science.gov (United States)

    Foyle, A.M.; Oertel, G.F.

    1997-01-01

    High-frequency Quaternary glacioeustasy resulted in the incision of six moderate- to high-relief fluvial erosion surfaces beneath the Virginia inner shelf and coastal zone along the updip edges of the Atlantic continental margin. Fluvial valleys up to 5 km wide, with up to 37 m of relief and thalweg depths of up to 72 m below modern mean sea level, cut through underlying Pleistocene and Mio-Pliocene strata in response to drops in baselevel on the order of 100 m. Fluvially incised valleys were significantly modified during subsequent marine transgressions as fluvial drainage basins evolved into estuarine embayments (ancestral generations of the Chesapeake Bay). Complex incised-valley fill successions are bounded by, or contain, up to four stacked erosional surfaces (basal fluvial erosion surface, bay ravinement, tidal ravinement, and ebb-flood channel-base diastem) in vertical succession. These surfaces, combined with the transgressive oceanic ravinement that generally caps incised-valley fills, control the lateral and vertical development of intervening seismic facies (depositional systems). Transgressive stratigraphy characterizes the Quaternary section beneath the Virginia inner shelf where six depositional sequences (Sequences I-VI) are identified. Depositional sequences consist primarily of estuarine depositional systems (subjacent to the transgressive oceanic ravinement) and shoreface-shelf depositional systems; highstand systems tract coastal systems are thinly developed. The Quaternary section can be broadly subdivided into two parts. The upper part contains sequences consisting predominantly of inner shelf facies, whereas sequences in the lower part of the section consist predominantly of estuarine facies. Three styles of sequence preservation are identified. Style 1, represented by Sequences VI and V, is characterized by large estuarine systems (ancestral generations of the Chesapeake Bay) that are up to 40 m thick, have hemicylindrical wedge geometries

  7. The promotion of geomorphosites on salt from Sovata - Praid and Turda using cultural and scientific tourism

    Science.gov (United States)

    Toma, B.; Irimus, I.; Petrea, D.

    2012-04-01

    The paper highlights the role of geomorphosites on salt, in experts and specialists training, in geography of tourism and planning, namely, the involvement of educational factor in defining managerial and marketing skills of future specialists in training. Geographical area of investigation belongs to the Transylvanian tectonic basin, overlapped to saliferous tectonic area from eastern Transylvania, represented by Praid - Sovata - Corund anticline and Sic -Cojocna - Turda anticline, analysis is focused on the Praid - Sovata and Turda diapirs. Saliferous area Praid - Sovata - Corund is situated on the contact area of the Transylvanian Basin with neo-eruptiv mountain chain of Eastern Carpathians, Calimani - Gurghiu - Harghita, and at the contact of Târnavelor Plateau with the orogen alignment of Gurghiu - Harghita Mountains. The salt body, in the horizontal plane, has a quasi-circular shape, slightly ellipsoidal, with diameters of 1.2 and 1.4 km, and is estimated to have a burial depth of 2.6 to 2.8 km. The salt massif from Praid, pierce the Mio-Pliocene blanket around and appears at the surface as diapir, flanked by sedimentary rocks that are partially covered by extrusive post-Pliocene volcanic formations and Quaternary deposits. Evaporitic deposits presents a varied lithology represented by gypsum, anhydrite, salt rock, potassium salt and celestine. The salt massif from Turda develops on the anticline Sic -Cojocna - Turda, oriented NE - SW, 2 km NE of Turda's downtown. It has an elongated shape, about 4 km, with widths ranging from 700 m to 200 m and also with a thickness ranging from 750 m to over 1000 m. In terms of stratigraphy, the salt massif is surrounded by deposits belonging to Badenian, Sarmatian and Quaternary. Due to salt dissolution by meteoric waters, carsto-saline lakes were formed, and due to ceiling collapse, because of an intensive exploitation, and infiltrations of rainwater and rivers, antropo-salted lakes were formed. The water and mud of

  8. Parametric study of the impact of waste pollutants on groundwater: the case of Abidjan District (Ivory Coast)

    Science.gov (United States)

    Agnès Kouamé, Amenan; Jaboyedoff, Michel; Tacher, Laurent; Derron, Marc-Henri; Franz, Martin

    2015-04-01

    Abidjan like numerous African cities is experiencing a significant and uncontrolled population growth. The annual growth rate is estimated at 3.99% by the National Institute of Statistics. This rapid population growth also generates growing needs in general and especially for drinking water and economic activities. In the District of Abidjan, groundwater comes from the Mio-Pliocene age aquifer called "Continental Terminal". This unconfined aquifer is the main source of water supply. Its lithology consists of four levels. Actually only the two upper levels outcrop and constitute the main part of the Continental Terminal aquifer. Some recent studies report a potential overexploitation and pollution of Abidjan groundwater (Jourda, 1986, Kouame 2007, Deh, 2013). This deterioration in water quality could be due to the release of domestic and industrial waste water, pesticide and fertilizer from crops and toxic waste sites containing high doses of organochlorines, of hydrogen sulfide and sulfides. This risk is also linked to the economic activities such as car workshops, gas stations and the sand exploitation in the lagoon. To observe the likely evolution of such contaminants in the subsurface and we developed hydrogeological models that couple groundwater flow and transport with FEFLOW software. The model is composed of a sandy layer where two constant hydraulic heads of 55 m and 0.2 m are imposed on the north and the south respectively. We carried out grain size analysis of some samples (E2, E3, E4, E5, and E6) which shows particle size ranging between 0.0001 mm and 8 mm. This grain size analysis performed by sieving underwater and laser indicates that these five soils are: loamy sand with traces of clay and gravel for E2 and E5; Sandy loam with traces of clay for E3; Sand with traces of clay and gravel for E4 and Sand with traces of silt and clay for E6. Their porosity and average values of permeability coefficient K measured in the laboratory range from 0.2 to 0

  9. Comparative zircon tephrochronology: correlating the Pliocene Bouse tephra, lower Colorado River trough, California, with the Lawlor Tuff of the Sonoma volcanic field, California

    Science.gov (United States)

    Harvey, J. C.

    2013-12-01

    Identification, correlation, and absolute dating of glassy volcanic ash and cryptically reworked pyroclastic deposits can be problematic. This is especially the case in strongly weathered samples where primary glass chemistry may not be preserved, or in lacustrine and fluvial environments where detrital materials can heavily bias bulk analysis or produce complex age distributions in single crystal dating approaches. These problems have frustrated numerous attempts to date a singular key ash horizon from the Mio-Pliocene Bouse Formation in southern California (fine-grained carbonate beds and clastic sediments derived from the Colorado River, deposited in the lower Colorado River Trough). Constraining the depositional age of the Bouse Formation is important for understanding the evolution of the Colorado River system, the uplift history of the Colorado Plateau, and the climate conditions involved in Colorado River evolution. Prior attempts to directly date the ash have been inconclusive. A K-Ar in glass date of 5.47 × 0.20 Ma (Shafiqullah et al., 1980) was questioned because of the potential disturbance of both the parent and daughter products of potassium decay in glass, and 40Ar/39Ar geochronology on bulk glass and bulk plagioclase separates (Spencer et al., 2000) produced discordant results. Recent glass chemistry correlation of the ash horizon to the 4.83 × 0.011 Ma Lawlor Tuff, Sonoma volcanic field, California (Sarna-Wojcicki et al., 2011), has also been contentious, because that age appears to conflict with the proposed onset of the delivery of Colorado River sediment through to the Gulf of California (Dorsey et al., 2007). To resolve the persistent age arguments, comparative zircon tephrochronology has been undertaken utilizing the single-crystal analysis capabilities of secondary ion mass spectrometry. Here, U-Pb zircon crystallization age spectra, U and Th abundances, and oxygen isotopic composition are presented which confirm the correlation of the Bouse

  10. Neogene Uplift and Exhumation of Plutonic Bodies in the Beni Bou Ifrour Massif (Nador, northeastern Morocco)

    Science.gov (United States)

    Lebret, Noëmie; Jolivet, Laurent; Branquet, Yannick; Bourdier, Jean-Louis; Jolivet, Marc; Marcoux, Eric

    2013-04-01

    In Neogene times, the whole Mediterranean Sea was the center of an intense magmatic activity. This post-collisional magmatism produced a large amount of volcanic edifices through the Alpine belts, together with some intrusives. These plutonic bodies can be associated with skarn-type mineralization, well-known in Elba Island or Serifos Island (Cyclades), where they are generally exhumed by detachment faults. In Morocco, the plutons hosted by the Beni Bou Ifrour massif are connected to the biggest skarn-type iron concentrations of the country (production > 60 Mt, reserves ≈ 25 Mt). The purpose of this work is to explain the late uplift of this massif and subsequent exhumation of the intrusives. As a final product of the Africa-Eurasia plate convergence since ca. 70 Ma, the Rif Mountains constitute the westernmost segment of the Mediterranean Alpine belts. In the oriental part of this range, volcanic summits and Paleozoic to Mesozoic massifs outcrop in the surrounding Mio-Pliocene plains. The Beni Bou Ifrour massif, in the Nador province, consists in a dome-shaped folded Mesozoic series (Domerian to Barremian) affected by a slight epizonal regional metamorphism (ca. 14-12 Ma), dislocated by Neogene NE-SW faults and eventually sealed by upper Miocene transgressive sediments. The hosted intrusives (7.58 ± 0.03 Ma; Duggen et al., 2005) are the plutonic equivalents to the potassic calc-alkaline lavas (andesites mainly) from the surrounding "satellite" volcanic massifs. They turn out to stand in higher topographic position than the younger shoshonitic lavas of the neighboring Gourougou stratovolcano (6.12 ± 0.01 Ma; Duggen et al., 2005). Previous studies have attributed this uplift to the action of normal faults (pull-apart basins; Guillemin & Houzay, 1982), thrusting (Kerchaoui, 1985; 1995) or even of a caldeira resurgence (El Bakkali, 1995). To discriminate against those exhumation mechanisms, field work has been performed, coming along with new cross-sections to

  11. 87Sr/86Sr-ratios, foraminiferal data and sedimentology of the Latest Miocene - Pliocene cyclic carbonates of La Désirade (Guadeloupe, France)

    Science.gov (United States)

    Weber*, P. J. N.; Baumgartner-Mora*, C.; Baumgartner*, P. O.

    2012-04-01

    La Désirade is a small island located east of Grande Terre and Basse Terre, the main islands of the Guadeloupe Archipelago in the Lesser Antilles Arc. La Désirade is an "forearc outer high" located immediately west of the trench where Atlantic crust is presently subducted under the Caribbean Plate. The "Limestone Table" (LT) of La Désirade has been considered as a Plio-Quaternary reefal deposit. However, the prominent feature of this reef slope. They document the mobilisation of carbonate material on an adjacent platform by storms and their gravitational emplacement. The provenance of both the reefal carbonate debris and the tuffaceous components must be to the west, i. e. Marie Galante and Grande Terre. We have studied the biochronology of both benthic and planktonic foraminifera and measured 87Sr/86Sr ratios of selected biogenic shells such as aragonitic gastropods, corals, echinoderms and foraminifera. Recrystallisation and preservation has been controlled by SEM, cathodoluminescence, carbon/oxygen isotopes and XRF to avoid diagenetically altered samples. Planktonic foraminifera of the "detrital offshore limestones" give a latest Miocene/early Pliocene age (lower zone N19), while 87Sr/86Sr -ratios cluster in the latest Miocene-earliest Pliocene, depending on the calibration applied. For the LT 87Sr/86Sr ratios from the base of the section cluster in the earliest Pliocene, while the top gives a late middle to late Pliocene age. These ages constrain the Neogene vertical tectonic movements of the island. We have also dated Pleistocene terraces and fringing reefs that are in an unconformable contact along paleocliffs with the Mio-Pliocene sediments. In the lower unit of the LT, sedimentary environments alternate between below wave base, muddy carbonates documenting glacioeustatic highstads, and wave-bedded, winnowed bioclastic carbonates representing lowstands. In the upper LT unit synsedimentary, tectonic subsidence must have decelerated, resulting in a

  12. Analyse quantitative du réseau hydrographique du bassin versant du Slănic (Roumanie

    Directory of Open Access Journals (Sweden)

    Florina Grecu

    2007-12-01

    Full Text Available L'étude porte sur le bassin versant du Slănic, un affluent du Buzău. Ce bassin de taille relativement réduite (433 km2 est situé dans la région des Carpates et des Subcarpates de la Courbure, région très active sur le plan sismique. Du point de vue lithologique, le bassin du Slănic correspond à des flyschs paléogènes et à des molasses mio-pliocènes. Ces roches peu résistantes ont facilité une forte érosion du relief. Actuellement, les précipitations présentent souvent une forte intensité, et elles se produisent fréquemment après des périodes de sécheresse. Elles sont ainsi très agressives et déclenchent une érosion intense. L'analyse de quelques paramètres morphométriques [grand nombre de segments de cours d'eau d'ordres 1 (5230 et 2 (944 ; densité élevée des segments par rapport à la superficie du bassin (environ 15 segments / km2 ; longueur moyenne réduite des segments d'ordre 1 (260 m par rapport à ceux d'ordre 2 (530 m] s'accorde avec des temps de concentration des eaux courts et une forte énergie des écoulements. La vitesse de réaction aux précipitations des segments d'ordres inférieurs est en outre favorisée par la répartition spatiale des pluies et par les conditions lithologiques.The study is focused on the Slănic basin which has a small size (433 km2. The hydrographical basin of Slănic, situated in the Carpathian and Subcarpathian Curvature, a very active from neotectonical viewpoint area, is a part of the Buzău basin. From a petrographic point of view, the Slănic hydrographic basin belongs to the paleogen flysch deposits (within the Carpathian sector and to the mio-pliocen molasse (within the Subcarpathian area latter formed by predominantely friable rocks which have encouraged deep fragmentation of the relief. Actual rainfalls are often very intensive, and they frequently occur after dry seasons. The analysis of morphometric parameters shows many elementary segments of first

  13. Chromosome Connections: Compelling Clues to Common Ancestry

    Science.gov (United States)

    Flammer, Larry

    2013-01-01

    Students compare banding patterns on hominid chromosomes and see striking evidence of their common ancestry. To test this, human chromosome no. 2 is matched with two shorter chimpanzee chromosomes, leading to the hypothesis that human chromosome 2 resulted from the fusion of the two shorter chromosomes. Students test that hypothesis by looking for…

  14. Bovids as indicators of Plio-Pleistocene paleoenvironments in east Africa.

    Science.gov (United States)

    Kappelman, J; Plummer, T; Bishop, L; Duncan, A; Appleton, S

    1997-01-01

    Reconstructions of the paleoenvironments of early hominids offer a framework for understanding hominid ecological and behavioral adaptations. Habitat reconstructions typically rely upon various biological or physical habitat indicators, and here we present reconstructions of the Plio-Pleistocene paleohabitats of Koobi Fora and Olduvai Gorge as based on fossil bovids (Artiodactyla: Bovidae). Bovids are the most common faunal element at most Neogene hominid and hominoid fossil localities and have been widely studied. This study addresses the functional morphology of the bovid femur through discriminant function analysis and provides additional support for the observation that certain features of the femur demonstrate clear correlations with the amount of vegetative cover in different modern habitats. The reconstructions for both Koobi Fora and Olduvai Gorge suggest that the full range of environments inhabited by living bovids was present during the Plio-Pleistocene. Koobi Fora appears to have had a somewhat higher percentage of more closed habitats than the relatively more open habitats of Olduvai Gorge. These habitat reconstructions are in broad agreement with other reconstructions based on a purely taxonomic approach to the bovid remains. Grounding our reconstructions of paleoenvironments in studies of functional morphology can help to develop a richer idea of the habitats and resources available to early hominids.

  15. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    As a non-hominid comparison set, we consider a random population of five-link robots with simplified joint angle and torque constraints. We generate 20,000 such robot models and sequentially optimize their throwing motion. Since good initial guesses are needed for each optimization, the robots are first arranged in ...

  16. Evolution & Phylogenetic Analysis: Classroom Activities for Investigating Molecular & Morphological Concepts

    Science.gov (United States)

    Franklin, Wilfred A.

    2010-01-01

    In a flexible multisession laboratory, students investigate concepts of phylogenetic analysis at both the molecular and the morphological level. Students finish by conducting their own analysis on a collection of skeletons representing the major phyla of vertebrates, a collection of primate skulls, or a collection of hominid skulls.

  17. Louis Leakey and Mary Leakey

    Indian Academy of Sciences (India)

    IAS Admin

    and archaeologists of the twentieth century whose discoveries have had a major influence on our understanding of human evolution. These discoveries were spectacular and brought popular ... However, it took a while for the concept of human evolution to be .... hominid fossil discoveries from East Africa could still have.

  18. Louis Leakey and Mary Leakey

    Indian Academy of Sciences (India)

    Permanent link: https://www.ias.ac.in/article/fulltext/reso/020/08/0667-0679. Keywords. Palaeoanthropology; human evolution; Louis Leakey; Mary Leakey; Africa; Olduvai gorge; fossil hominids. Author Affiliations. Rajan Gaur1. Department of Anthropology, Panjab University, Sector 14, Chandigarh UT 160 014, India ...

  19. Facial orientation and facial shape in extant great apes: a geometric morphometric analysis of covariation.

    Science.gov (United States)

    Neaux, Dimitri; Guy, Franck; Gilissen, Emmanuel; Coudyzer, Walter; Vignaud, Patrick; Ducrocq, Stéphane

    2013-01-01

    The organization of the bony face is complex, its morphology being influenced in part by the rest of the cranium. Characterizing the facial morphological variation and craniofacial covariation patterns in extant hominids is fundamental to the understanding of their evolutionary history. Numerous studies on hominid facial shape have proposed hypotheses concerning the relationship between the anterior facial shape, facial block orientation and basicranial flexion. In this study we test these hypotheses in a sample of adult specimens belonging to three extant hominid genera (Homo, Pan and Gorilla). Intraspecific variation and covariation patterns are analyzed using geometric morphometric methods and multivariate statistics, such as partial least squared on three-dimensional landmarks coordinates. Our results indicate significant intraspecific covariation between facial shape, facial block orientation and basicranial flexion. Hominids share similar characteristics in the relationship between anterior facial shape and facial block orientation. Modern humans exhibit a specific pattern in the covariation between anterior facial shape and basicranial flexion. This peculiar feature underscores the role of modern humans' highly-flexed basicranium in the overall integration of the cranium. Furthermore, our results are consistent with the hypothesis of a relationship between the reduction of the value of the cranial base angle and a downward rotation of the facial block in modern humans, and to a lesser extent in chimpanzees.

  20. Cut marks on the Bodo cranium: a case of prehistoric defleshing.

    Science.gov (United States)

    White, T D

    1986-04-01

    Cut marks were discovered on the Middle Pleistocene Bodo cranium from Ethiopia. The cut marks most closely resemble experimental damage caused by the application of stone tools to fresh bone. This discovery constitutes the earliest solid evidence for intentional defleshing of a human ancestor and offers new research avenues for the investigation of early hominid mortuary practices.

  1. Fulltext PDF

    Indian Academy of Sciences (India)

    1997-05-08

    May 8, 1997 ... Less Brain, Less Brawn: A. New Evolutionary View of. Man. JA Santosh. 6ne familiar and common depiction of man's evolution can be found in abundance and in a variety of places from textbooks to popular media. This is an illustration portraying the profiles of a group of hominids moving along.

  2. 74-----------------------------~-------------RE-SONANCEIJan-ua-rY-1-99-S

    Indian Academy of Sciences (India)

    1997-05-08

    May 8, 1997 ... media. This is an illustration portraying the profiles of a group of hominids moving along in line through the trail of evolutionary time. The trail begins with .... To correct any bias that might have crept into the analysis because of unequal samples from different latitudes and sexes, an analysis filtering out these.

  3. Beyond the Pleistocene: Using Phylogeny and Constraint to Inform the Evolutionary Psychology of Human Mating

    Science.gov (United States)

    Eastwick, Paul W.

    2009-01-01

    Evolutionary psychologists explore the adaptive function of traits and behaviors that characterize modern Homo sapiens. However, evolutionary psychologists have yet to incorporate the phylogenetic relationship between modern Homo sapiens and humans' hominid and pongid relatives (both living and extinct) into their theorizing. By considering the…

  4. On the Measurement of Morphology and Its Change.

    Science.gov (United States)

    1982-03-01

    craniometry . For Example, the figures analyzed by Sneath (1967) for the chimpanzee Pan troglodytes and three hominid species were reanalyzed using RFTRA. The...approaches are available in the literature un craniometry (see Walker and Kowalskl, 1971; Bookstein, 1978). Among the most successful of these types

  5. Original Synthetic Article: The relationships between occlusion and ...

    African Journals Online (AJOL)

    Materials and Methods: These correlations were analyzed by using a metric methodology applied to x-rays or CT scan images of extant and fossil skulls. Results and conclusions: This approach presents major interests for the study of occluso-postural balances in fossil hominids as well as for the analysis of the evolutionary ...

  6. The Power of Natural Selection: A Guided Investigation of Three Case Studies

    Science.gov (United States)

    Beachly, William

    2010-01-01

    I describe a quantitative approach to three case studies in evolution that can be used to challenge college freshmen to explore the power of natural selection and ask questions that foster a deeper understanding of its operation and relevance. Hemochromatosis, the peppered moth, and hominid cranial capacity are investigated with a common algebraic…

  7. Zum Ursprung der Hominidae

    Science.gov (United States)

    Henke, Winfried

    1981-08-01

    A fundamental problem of hominisation is the branching of the human lineage leading to the genus Homo from other hominoids. At present discussed hypotheses of a Miocene separation of the pongid and hominid lineage are described under consideration of numerous new fossils from Europe, Asia and Africa. Of special interest is the possibility of an adhominisation of the genus Australopithecus (including A. afarensis).

  8. Baboon feeding ecology informs the dietary niche of Paranthropus boisei.

    Directory of Open Access Journals (Sweden)

    Gabriele A Macho

    Full Text Available Hominins are generally considered eclectic omnivores like baboons, but recent isotope studies call into question the generalist status of some hominins. Paranthropus boisei and Australopithecus bahrelghazali derived 75%-80% of their tissues' δ(13C from C4 sources, i.e. mainly low-quality foods like grasses and sedges. Here I consider the energetics of P. boisei and the nutritional value of C4 foods, taking into account scaling issues between the volume of food consumed and body mass, and P. boisei's food preference as inferred from dento-cranial morphology. Underlying the models are empirical data for Papio cynocephalus dietary ecology. Paranthropus boisei only needed to spend some 37%-42% of its daily feeding time (conservative estimate on C4 sources to meet 80% of its daily requirements of calories, and all its requirements for protein. The energetic requirements of 2-4 times the basal metabolic rate (BMR common to mammals could therefore have been met within a 6-hour feeding/foraging day. The findings highlight the high nutritional yield of many C4 foods eaten by baboons (and presumably hominins, explain the evolutionary success of P. boisei, and indicate that P. boisei was probably a generalist like other hominins. The diet proposed is consistent with the species' derived morphology and unique microwear textures. Finally, the results highlight the importance of baboon/hominin hand in food acquisition and preparation.

  9. Baboon feeding ecology informs the dietary niche of Paranthropus boisei.

    Science.gov (United States)

    Macho, Gabriele A

    2014-01-01

    Hominins are generally considered eclectic omnivores like baboons, but recent isotope studies call into question the generalist status of some hominins. Paranthropus boisei and Australopithecus bahrelghazali derived 75%-80% of their tissues' δ(13)C from C4 sources, i.e. mainly low-quality foods like grasses and sedges. Here I consider the energetics of P. boisei and the nutritional value of C4 foods, taking into account scaling issues between the volume of food consumed and body mass, and P. boisei's food preference as inferred from dento-cranial morphology. Underlying the models are empirical data for Papio cynocephalus dietary ecology. Paranthropus boisei only needed to spend some 37%-42% of its daily feeding time (conservative estimate) on C4 sources to meet 80% of its daily requirements of calories, and all its requirements for protein. The energetic requirements of 2-4 times the basal metabolic rate (BMR) common to mammals could therefore have been met within a 6-hour feeding/foraging day. The findings highlight the high nutritional yield of many C4 foods eaten by baboons (and presumably hominins), explain the evolutionary success of P. boisei, and indicate that P. boisei was probably a generalist like other hominins. The diet proposed is consistent with the species' derived morphology and unique microwear textures. Finally, the results highlight the importance of baboon/hominin hand in food acquisition and preparation.

  10. A new interdisciplinary approach to the study of the origins of traditional polyphony

    Directory of Open Access Journals (Sweden)

    Jordania Joseph

    2015-01-01

    Full Text Available The article discusses a new model of the origins of choral singing in the context of human evolutionary history. Hominid interaction with predators is seen as a crucial force in the evolution of human morphology and behaviour. Group singing and dancing, with body painting and the use of masks, are perceived as critical elements of the strategy to deter predators and to put hominids into an altered state of consciousness. In this state, humans do not feel fear and pain and are ready to sacrifice their lives for the common goal. This psychological condition is still important to many human group activities, particularly in religion and the military. The mosaic distribution of polyphonic traditions is discussed in the context of the origins of language and articulated speech.

  11. Development and progress: advancing towards environmental crisis

    International Nuclear Information System (INIS)

    Gomez G, Luis Jair

    2011-01-01

    Physical, biological and social evolution is doubtless. One of its first manifestations is the arrival of technique when hominids emerge from pre-hominids. Those first technical developments implied a new relation man/environment that was expressed in three components that appeared successively and pushed each other in time and space like this: dominion over nature, population concentration (urbanism), and population growth. Techniques are to generate three notorious effects on the relation man/nature: 1. Deep intervention on the physical environment: mining and industrial transformation processes; 2. Deep intervention on the biological environment: development of agriculture with a decrease in biodiversity; and 3. Deep intervention on the social environment: going from a pre-modern communitarian world, to the individualism of modernity; and from the agrarian field to the big city. All these technical developments boosted dominion of the technosphere over the ecosphere, which led to the appearance of the Environmental Crisis, whose most notable manifestation is Climatic Change.

  12. Brief communication: Is variation in the cranial capacity of the Dmanisi sample too high to be from a single species?

    Science.gov (United States)

    Lee, Sang-Hee

    2005-07-01

    This study uses data resampling to test the null hypothesis that the degree of variation in the cranial capacity of the Dmanisi hominid sample is within the range variation of a single species. The statistical significance of the variation in the Dmanisi sample is examined using simulated distributions based on comparative samples of modern humans, chimpanzees, and gorillas. Results show that it is unlikely to find the maximum difference observed in the Dmanisi sample in distributions of female-female pairs from comparative single-species samples. Given that two sexes are represented, the difference in the Dmanisi sample is not enough to reject the null hypothesis of a single species. Results of this study suggest no compelling reason to invoke multiple taxa to explain variation in the cranial capacity of the Dmanisi hominids. (c) 2004 Wiley-Liss, Inc

  13. Hiperactivación adrenal, noxas y hominización Adrenal hyperactivity, injuries and hominization

    Directory of Open Access Journals (Sweden)

    William Alvarez Gaviria

    2001-02-01

    Full Text Available En esta revisión se postula que la hominización es un subproducto del ajuste endocrino-metabólico a que fueron sometidos los ancestros de los homínidos hace unos 5 millones de años. Se demuestra un mayor índice de adrenalización en los homínidos que pudiera en parte explicar nuestro fenotipo, nuestra conducta y la mayor propensión a determinadas patologías. In this revision it is postulated that the hominization is a by-product of the endocrine-metabolic adjustment to that hominid ancestors were subjected about 5 million years ago. A bigger adrenalization index is demonstrated in the hominids that partly could explain our fenotype, our behavior and the biggest propensity to certain pathologies.

  14. Denisovans, Melanesians, Europeans, and Neandertals: The Confusion of DNA Assumptions and the Biological Species Concept.

    Science.gov (United States)

    Caldararo, Niccolo

    2016-08-01

    A number of recent articles have appeared on the Denisova fossil remains and attempts to produce DNA sequences from them. One of these recently appeared in Science by Vernot et al. (Science 352:235-239, 2016). We would like to advance an alternative interpretation of the data presented. One concerns the problem of contamination/degradation of the determined DNA sequenced. Just as the publication of the first Neandertal sequence included an interpretation that argued that Neandertals had not contributed any genes to modern humans, the Denisovan interpretation has considerable influence on ideas regarding human evolution. The new papers, however, confuse established ideas concerning the nature of species, as well as the use of terms like premodern, Archaic Homo, and Homo heidelbergensis. Examination of these problems presents a solution by means of reinterpreting the results. Given the claims for gene transfer among a number of Mid Pleistocene hominids, it may be time to reexamine the idea of anagenesis in hominid evolution.

  15. The First Joke: Exploring the Evolutionary Origins of Humor

    Directory of Open Access Journals (Sweden)

    Joseph Polimeni

    2006-01-01

    Full Text Available Humor is a complex cognitive function which often leads to laughter. Contemporary humor theorists have begun to formulate hypotheses outlining the possible innate cognitive structures underlying humor. Humor's conspicuous presence in the behavioral repertoire of humankind invites adaptive explanations. This article explores the possible adaptive features of humor and ponders its evolutionary path through hominid history. Current humor theories and previous evolutionary ideas on humor are reviewed. In addition, scientific fields germane to the evolutionary study of humor are examined: animal models, genetics, children's humor, humor in pathological conditions, neurobiology, humor in traditional societies and cognitive archeology. Candidate selection pressures and associated evolutionary mechanisms are considered. The authors conclude that several evolutionary-related topics such as the origins of language, cognition underlying spiritual feelings, hominid group size, and primate teasing could have special relevance to the origins of humor.

  16. Additional results on palaeomagnetic stratigraphy of the Koobi Fora Formation, east of Lake Turkana (Lake Rudolf), Kenya

    Science.gov (United States)

    Hillhouse, J.W.; Ndombi, J.W.M.; Cox, A.; Brock, A.

    1977-01-01

    The magnetostratigraphy of the hominid-bearing sediments exposed east of Lake Turkana has been strengthened by new palaeomagnetic results. Ages obtained from several tuffs by the 40Ar/39Ar method suggest an approxmate match between the observed magnetozones and the geomagnetic polarity time scale; however, the palaeomagnetic results are also compatible with a younger chronology suggested by conventional K-Ar dating of the KBS Tuff. ?? 1977 Nature Publishing Group.

  17. Culture, Urbanism and Changing Human Biology

    OpenAIRE

    Schell, L.M.

    2014-01-01

    Anthropologists have long known that human activity driven by culture changes the environment. This is apparent in the archaeological record and through the study of the modern environment. Perhaps the largest change since the paleolithic era is the organization of human populations in cities. New environments can reshape human biology through evolution as shown by the evolution of the hominid lineage. Evolution is not the only process capable of reshaping our biology. Some changes in our hum...

  18. Oreopithecus was a bipedal ape after all: Evidence from the iliac cancellous architecture

    Science.gov (United States)

    Rook, Lorenzo; Bondioli, Luca; Köhler, Meike; Moyà-Solà, Salvador; Macchiarelli, Roberto

    1999-01-01

    Textural properties and functional morphology of the hip bone cancellous network of Oreopithecus bambolii, a 9- to 7-million-year-old Late Miocene hominoid from Italy, provide insights into the postural and locomotor behavior of this fossil ape. Digital image processing of calibrated hip bone radiographs reveals the occurrence of trabecular features, which, in humans and fossil hominids, are related to vertical support of the body weight, i.e., to bipedality. PMID:10411955

  19. Effective Population Size Is Positively Correlated with Levels of Adaptive Divergence among Annual Sunflowers

    OpenAIRE

    Strasburg, Jared L.; Kane, Nolan C.; Raduski, Andrew R.; Bonin, Aurélie; Michelmore, Richard; Rieseberg, Loren H.

    2010-01-01

    The role of adaptation in the divergence of lineages has long been a central question in evolutionary biology, and as multilocus sequence data sets have become available for a wide range of taxa, empirical estimates of levels of adaptive molecular evolution are increasingly common. Estimates vary widely among taxa, with high levels of adaptive evolution in Drosophila, bacteria, and viruses but very little evidence of widespread adaptive evolution in hominids. Although estimates in plants are ...

  20. A new species of great ape from the late Miocene epoch in Ethiopia.

    Science.gov (United States)

    Suwa, Gen; Kono, Reiko T; Katoh, Shigehiro; Asfaw, Berhane; Beyene, Yonas

    2007-08-23

    With the discovery of Ardipithecus, Orrorin and Sahelanthropus, our knowledge of hominid evolution before the emergence of Pliocene species of Australopithecus has significantly increased, extending the hominid fossil record back to at least 6 million years (Myr) ago. However, because of the dearth of fossil hominoid remains in sub-Saharan Africa spanning the period 12-7 Myr ago, nothing is known of the actual timing and mode of divergence of the African ape and hominid lineages. Most genomic-based studies suggest a late divergence date-5-6 Myr ago and 6-8 Myr ago for the human-chimp and human-gorilla splits, respectively-and some palaeontological and molecular analyses hypothesize a Eurasian origin of the African ape and hominid clade. We report here the discovery and recognition of a new species of great ape, Chororapithecus abyssinicus, from the 10-10.5-Myr-old deposits of the Chorora Formation at the southern margin of the Afar rift. To the best of our knowledge, these are the first fossils of a large-bodied Miocene ape from the African continent north of Kenya. They exhibit a gorilla-sized dentition that combines distinct shearing crests with thick enamel on its 'functional' side cusps. Visualization of the enamel-dentine junction by micro-computed tomography reveals shearing crest features that partly resemble the modern gorilla condition. These features represent genetically based structural modifications probably associated with an initial adaptation to a comparatively fibrous diet. The relatively flat cuspal enamel-dentine junction and thick enamel, however, suggest a concurrent adaptation to hard and/or abrasive food items. The combined evidence suggests that Chororapithecus may be a basal member of the gorilla clade, and that the latter exhibited some amount of adaptive and phyletic diversity at around 10-11 Myr ago.

  1. Amphibians and squamate reptiles from the latest early Pleistocene of Cueva Victoria (Murcia, southeastern Spain, SW Mediterranean): Paleobiogeographic and paleoclimatic implications

    OpenAIRE

    BLAIN, H.A.; BAILON, S.; AGUSTÍ BALLESTER, J.

    2009-01-01

    The karstic filling of Cueva Victoria in southeastern Spain, dated from the latest early Pleistocene (ca. 1.1 Ma), is famous for providing primate fossil remains (Theropithecus) of typical African origin, in the general controversy on the antiquity of the first hominid settlements in Western Europe and their possible entrance into Europe through the Strait of Gibraltar. Cueva Victoria has also furnished the following fauna of anurans and squamate reptiles: cf. Pelodytes sp. (Pelodytidae), ...

  2. Actions speak louder than words in socially foraging human groups

    OpenAIRE

    Sumner, Seirian; King, Andrew J.

    2011-01-01

    Social foraging in humans has a deep evolutionary history: early hominids searched for dispersed food sources in a patchy, uncertain environment. A fundamental assumption is that social foragers benefit by exchanging information about food sources, in order to make collective decisions based on pooled information. We conducted the first experimental test of this assumption, and showed that, as predicted, communication significantly enhanced group performance. A further, unexpected result was ...

  3. The earliest evidence of true lambdoid craniosynostosis: the case of "Benjamina", a Homo heidelbergensis child.

    Science.gov (United States)

    Gracia, Ana; Martínez-Lage, Juan F; Arsuaga, Juan-Luis; Martínez, Ignacio; Lorenzo, Carlos; Pérez-Espejo, Miguel-Angel

    2010-06-01

    The authors report the morphological and neuroimaging findings of an immature human fossil (Cranium 14) diagnosed with left lambdoid synostosis. The skull was recovered at the Sima de los Huesos site in Atapuerca (Burgos, Spain). Since the human fossil remains from this site have been dated to a minimum age of 530,000 years, this skull represents the earliest evidence of craniosynostosis occurring in a hominid. A brief historical review of craniosynostosis and cranial deformation is provided.

  4. Cranial morphology of Australopithecus afarensis: a comparative study based on a composite reconstruction of the adult skull.

    Science.gov (United States)

    Kimbel, W H; White, T D; Johanson, D C

    1984-08-01

    The Pliocene hominid species Australopithecus afarensis is represented by cranial, dental, and mandibular remains from Hadar, Ethiopia, and Laetoli, Tanzania. These fossils provide important information about the cranial anatomy of the earliest known hominids. Because complete crania or skulls are not known, we produced a composite reconstruction of an adult male skull based on 13 specimens from the Hadar Formation. The reconstruction serves as a testable hypothesis regarding functional relationships in the A. afarensis skull and is the basis for the comparative study presented here. We examine six major aspects of cranial and mandibular anatomy. We combine our results with those of White et al. (1981) in a discussion of alternate hypotheses of early hominid phylogeny. In the cranium, jaws, and teeth A. afarensis exhibits a morphological pattern that we interpret as primitive for the Hominidae. Homo habilis retains a number of these primitive features for which A. africanus, A. robustus, and A. boisei share derived character states, particularly in the masticatory apparatus. Homo and "robust" species of Australopithecus share a suite of derived cranial base features. These shared traits may relate to upper facial orthognathium which is also common to these taxa and are probably indicative of parallelism rather than a close phylogenetic relationship. The cranial base characteristics of A.L. 333-45 do not, contrary to Olson's (1981) claims, provide evidence for an A. afarensis--"robust" Australopithecus sister group. When the range of mastoid variation in extant African pongids and A. afarensis is examined thoroughly, the Pliocene hominid appears to retain a primitive, rather than derived, morphology.

  5. Neanderthal teeth from Moula-Guercy, Ardèche, France.

    Science.gov (United States)

    Hlusko, Leslea J; Carlson, Joshua P; Guatelli-Steinberg, Debbie; Krueger, Kristin L; Mersey, Ben; Ungar, Peter S; Defleur, Alban

    2013-07-01

    Here we describe dental remains from a Neanderthal fossil assemblage from Moula-Guercy, France. Our report demonstrates that the Moula-Guercy hominid remains contribute important morphological, developmental, and behavioral data to understanding Neanderthal evolutionary history. We include gross comparative morphological descriptions and enamel surface microstructure and microwear data. These teeth reveal numerous characteristics that are diagnostic of Neanderthals and provide no evidence for the presence of any other hominid taxa. Enamel growth increment data from the Moula-Guercy specimens yield evidence of a Neanderthal pattern of development, although at the lower end of the range of variation. The presence of a significant number of linear enamel hypoplasias indicates that these individuals were stressed during childhood. Molar microwear data suggest that these Neanderthals did not differ significantly from modern humans in terms of the fracture properties of the food they were consuming. The incisor microwear and macro striations provide evidence that these individuals may have been using their anterior teeth as tools, similar to the practices of several modern human populations such as the Inuit, Ipiutak, and Australian Aboriginals, and reminiscent of evidence from other Neanderthals from Krapina, Croatia, as well as the 600,000 year old hominids from Sima de los Huesos, Spain. Am J Phys Anthropol 151:477-491, 2013.© 2013 Wiley Periodicals, Inc. Copyright ©2013 Wiley Periodicals, Inc.

  6. The temporal bones from Sima de los Huesos Middle Pleistocene site (Sierra de Atapuerca, Spain). A phylogenetic approach.

    Science.gov (United States)

    Martínez, I; Arsuaga, J L

    1997-01-01

    Three well-preserved crania and 22 temporal bones were recovered from the Sima de los Huesos Middle Pleistocene site up to and including the 1994 field season. This is the largest sample of hominid temporal bones known from a single Middle Pleistocene site and it offers the chance to characterize the temporal bone morphology of an European Middle Pleistocene population and to study the phylogenetic relationships of the SH sample with other Upper and Middle Pleistocene hominids. We have carried out a cladistic analysis based on nine traits commonly used in phylogenetic analysis of Middle and Late Pleistocene hominids: shape of the temporal squama superior border, articular eminence morphology, contribution of the sphenoid bone to the median glenoid wall, postglenoid process projection, tympanic plate orientation, presence of the styloid process, mastoid process projection, digastric groove morphology and anterior mastoid tubercle. We have found two autapomorphies on the Home erectus temporal bone: strong reduction of the postglenoid process and absence of the styloid process. Modern humans, Neandertals and the Middle Pleistocene fossils from Europe and Africa constitute a clade characterized by a convex superior border of the temporal squama. The European Middle Pleistocene fossils from Sima de los Huesos, Petralona, Steinheim, Bilzingsleben and Castel di Guido share a Neandertal apomorphy: a relatively flat articular eminence. The fossils from Ehringsdorf, La Chaise Suardi and Biache-Saint-Vaast also display another Neandertal derived trait: an anteriorly obliterated digastric groove. Modern humans and the African Middle Pleistocene fossils share a synapomorphy: a sagittally orientated tympanic plate.

  7. [Survival of the fattest: the key to human brain evolution].

    Science.gov (United States)

    Cunnane, Stephen C

    2006-01-01

    The circumstances of human brain evolution are of central importance to accounting for human origins, yet are still poorly understood. Human evolution is usually portrayed as having occurred in a hot, dry climate in East Africa where the earliest human ancestors became bipedal and evolved tool-making skills and language while struggling to survive in a wooded or savannah environment. At least three points need to be recognised when constructing concepts of human brain evolution : (1) The human brain cannot develop normally without a reliable supply of several nutrients, notably docosahexaenoic acid, iodine and iron. (2) At term, the human fetus has about 13 % of body weight as fat, a key form of energy insurance supporting brain development that is not found in other primates. (3) The genome of humans and chimpanzees is human brain become so much larger, and how was its present-day nutritional vulnerability circumvented during 5-6 million years of hominid evolution ? The abundant presence of fish bones and shellfish remains in many African hominid fossil sites dating to 2 million years ago implies human ancestors commonly inhabited the shores, but this point is usually overlooked in conceptualizing how the human brain evolved. Shellfish, fish and shore-based animals and plants are the richest dietary sources of the key nutrients needed by the brain. Whether on the shores of lakes, marshes, rivers or the sea, the consumption of most shore-based foods requires no specialized skills or tools. The presence of key brain nutrients and a rich energy supply in shore-based foods would have provided the essential metabolic and nutritional support needed to gradually expand the hominid brain. Abundant availability of these foods also provided the time needed to develop and refine proto-human attributes that subsequently formed the basis of language, culture, tool making and hunting. The presence of body fat in human babies appears to be the product of a long period of

  8. Middle Palaeolithic burial is not a dead issue: the view from Qafzeh, Saint-Césaire, Kebara, Amud, and Dederiyeh.

    Science.gov (United States)

    Gargett, R H

    1999-07-01

    Inferences of purposeful Middle Palaeolithic (MP) burial are almost universally accepted, despite published arguments that the pre-1960s discoveries are equally well explained by natural processes. In the modern human origins debate (perhaps the most hotly disputed question in palaeoanthropology) inferences of MP burial are crucial in arguments for an early Upper Pleistocene emergence of modern humans. The present paper contributed to that debate by re-examining a number of post-1960s excavations of MP hominid remains. Because these were excavated with meticulous attention to depositional circumstances and stratigraphic context, most palaeoanthropologists consider these inferences of purposeful burial to be based on irrefutable evidence. This paper focuses on the reasoning behind such claims, especially the assumption that articulated sketetal material is prima facie evidence for deliberate burial. First it reviews a range of processes operating in caves and rockshelters that condition the probability of articulated skeletal material preserving without hominid intervention. Processes such as deposition, decomposition, and disturbance are inherently more variable in caves and rockshelters than is usually acknowledged. The first section concludes that purposeful protection is not necessary to account for the preservation of articulated skeletal remains. The second part of the paper examines the published record from Qafzeh, Saint-Césaire, Kebara, Amud and Dederiyeh, where the majority of the remains claimed to have been buried are fragmented, incomplete, and disarticulated. This re-examination suggests that in all of the post-1960s cases of putative burial, the hominid remains occur in special depositional circumstances, which by themselves are sufficient to account for the preservation in evidence at these sites. This conclusion severely weakens arguments for purposeful burial at the five sites. Moreover, the equivocal nature of the evidence in the more recent

  9. The antler finds at Bilzingsleben, excavations 1969-1993

    Directory of Open Access Journals (Sweden)

    Jürgen Vollbrecht

    2000-09-01

    Full Text Available 2820 antler remains from the Lower Palaeolithic site of Bilzingsleben, Thuringia, Germany (excavations 1969-1993 were the subject of detailed investigations. The two major goals were: 1.the consideration of taphonomic aspects 2.the critical evaluation of suggestions about artificial modifications to the antler material A detailed morphological description of the antler material provided the basis for the investigation. A prerequisite was the transfer of provenance data onto an x-y coordinate grid. Taphonomic aspects considered in this work include the relative frequencies of antler elements, estimates regarding the minimum number of individual deer, their age structure and seasonality, and, insofar as the condition of the antlers allowed, the classification of surface preservation, size classes and spatial distribution of the finds. The assemblage of antler finds, the majority of which seems to have come from red deer, is dominated by small fragments, mostly of tines. About one quarter of the finds are larger than 150 mm. Lower beams are more abundant than upper beams (e.g. crowns. Detailed counting, substantiated by systematic reconstruction, shows that in general the antlers are incomplete. After reconstruction of unshed antlers, it was possible to assess the minimum number of heads at 150 animals. Preliminary counting of postcranial and cranial (non antler cervid material points to about 70 cervids. Intentional accumulation of antlers by hominids can only be accepted as the reason for these disproportionate figures if other site formation processes can be ruled out. In fact, the correlation between sediment thickness and maximum antler densities, at least for finds smaller than 120mm, suggests that fluvial accumulation has to be taken into account as a probable element of the site formation history. Further, the mixture of unifacially abraded finds together with finds that exhibit bifacial abrasion points to a succession of changing fluvial

  10. Stable isotope-based Plio-Pleistocene southern hemisphere climate and vegetation reconstructions (Chiwondo Beds, Northern Malawi)

    Science.gov (United States)

    Luedecke, T.; Thiemeyer, H.; Schrenk, F.; Mulch, A.

    2013-12-01

    Oxygen and carbon isotope geochemistry of multi-proxy archives is a powerful tool to reconstruct paleoclimatic and paleoenvironmental conditions in particular when climate seasonality plays a key role in the evolution of ecosystems. Here we present the first pedogenic Plio-Pleistocene long-term East-African carbon, oxygen and clumped isotope (Δ47) records from some of the earliest hominid fossil sites in Eastern Africa. The studied 5.0 to 0.6 Ma paleosol, fluviatile, and lacustrine deposits of the Chiwondo Beds (Karonga-Chilumba area, NE shore of Lake Malawi) comprise abundant pedogenic carbonates and fossil remains of a diverse fauna which are dominated by large terrestrial mammals. The sediments are also home to two hominid fossil finds, a maxillary fragment of Paranthropus boisei and a mandible of Homo rudolfensis, both dated around 2.4 Ma. Here, we present stable carbon (δ13C) and oxygen (δ18O) isotope data from fossil enamel of different suid, bovid, and equid species as well as δ13C and δ18O values of pedogenic carbonate. We complement the latter by clumped isotope data as proxy for soil temperature. Our data represent the first southern hemisphere record in the East African Rift (EAR), a region particularly interesting for reconstructing vegetation patterns and correlating these across the ITCZ with data on the evolution and migration of early hominids. As our study site is situated between the well-known hominid-bearing sites of eastern and southern Africa it fills an important geographical gap for early hominid research. The δ13C values of enamel and pedogenic carbonate assess the evolutionary history of C3 and C4 biomass which is closely linked to climate patterns in the Malawi Rift Valley during the time of early hominid evolution. The reconstruction of the development of C4-grasslands give insights of changing atmospheric CO2-concentration, seasonality and distribution of precipitation, and the retreat of tree cover. Results of almost 500

  11. Ophiolite Emplacement and the Effects of the Subduction of the Active Chile Ridge System: Heterogeneous Paleostress Regimes Recorded in the Taitao Ophiolite (Southern Chile Emplazamiento de ofiolitas y los efectos de la subducción de la dorsal activa de Chile: Regímenes heterogéneos de paleostress registrados en la Oflolita Taitao (Sur de Chile

    Directory of Open Access Journals (Sweden)

    Eugenio E Veloso

    2009-01-01

    Full Text Available The repeated north and southward migration of the Chile Triple junction, offshore the Península de Taitao, is expected to have imposed contrasting stress fields in the forearc for the last 6 Ma because of changes in convergence direction and rate of subducting plates. NNW-SSE to E-W and minor NE-SW striking brittle faults developed in the plutonic units of the Mio-Pliocene Taitao Ophiolite, whereas NNE-SSW and minor NW-SE trending faults developed in its eastern border (Bahía Barrientes fault-zone. These brittle faults are studied to elucídate the style of ophiolite emplacement and the tectonic effects resulting from the alternated migration of the Chile Triple junction in the área. Analyses of heterogeneous fault-slip data on both áreas suggest that faults were activated by different stress fields. Two different compressional stress fields were identified in the plutomc units (A and B, whereas three different stress fields, ranging from compressional to strike-slip, were identified in the BahíaBarrientos fault-zone (C, D and E. Calculated directions of Oj axes for A, C, D and E solutions are mostly E-W trending, roughly similar to the convergence direction of subducting plates, whereas that for B solution is counterclockwise rotated ca. 60° with respect to the previous E-W trend. Brittle structures related to solution B were attributed to an early deformation of the ophiolite, most probably developed shortly after its emplacement {ca. 6 Ma. These structures were further counterclockwise rotated, while new structures (related to solution A developed in the plutomc units in order to absorb the continuous deformation. In the eastern margin of the ophiolite, the stress field divided inte compressional and strike-slip components. During periods of relatively strong compression (fast subduction of the Nazca píate, the fault-zone experienced well defined compressional and strike-slip movements (solutions C and D. In contrast, during periods of

  12. La châine andine du Pérou Central: chronologie, orientation et styles des phases tectoniques du Tertiaire Supérieur - Aperçus sur la Tectonique Quaternaire

    Directory of Open Access Journals (Sweden)

    1975-01-01

    fase de deformaciones quebradizas del plioceno, según una dirección de acortamiento N 090 (entre 8 y 4,5 M A. Una fase mioceno reciente (entre 14 y 10,5 M.A. con dirección N 000 en las Altas Mesetas y quizás de dirección N 045 en la Cordillera Occidental da deformaciones quebradizas pero con una ligera tectónica flexible La fase mioceno antiguo (entre 21 y 14 M.A. está caracterizada por una dirección N 045, estructuras quebradizas y anchas estructuras flexibles. La fase oligoceno inferior (entre 21,5 y 40 M.A. concierne a esfuerzos mucho más importantes en estructuras mas profundas. Las fases mioceno y plioceno están superpuestas. El estudio de la falla de Gran Bretaña confirma estos resultados sin que se pueda tener la prueba de dos fases mioceno se trata de un accidente de descolgamiento con escasos desechos horizontales. Las fallas de la zona de La Oroya-Junín-Tarma tienen una geometría semejante al accidente de Gran Bretaña: se pueden observar tres fases sin que sea posible darles una fecha pero sus características corresponden a las fases plioceno, mioceno y oligoceno inferior. Algunas observaciones en la Cordillera Blanca parecen relacionarse a las del Sur de Huancavelica, pero quedan por precisar. El cuaternario muestra una tectónica compresiva de direcciones N 130 en la Cordillera Blanca y San Ramón, N 000 y N 040 en la cuenca de Huancayo (eventualmente también N 075 siguiendo la edad de la formación Jauja. No se ha observado fallas normales mas que en la Cordillera Blanca (¿distensión? ¿subida del macizo granítico?. The mio-pliocene tectonic episodes are studied in many sectors of the Central Peruvian Andes South of Huancavelica (Choclococha, Huachocolpa, Lircay, a pliocene episode of breaking compression but with a light folding tectonic The ancient miocene episode (between 8 and 4.5 m y.. A recent miocene episode (between 14 and 105 m.y of direction N 000 in the High Plateaux and may be of direction N 045 in the western chain of

  13. Fish as a proxy for African paleogeography: results from both extant and fossil taxa and prospects to constrain faunal exchange pathway through time

    Science.gov (United States)

    Otero, Olga; Joordens, Josephine; Dettai, Agnès; Christ, Leemans; Pinton, Aurélie

    2016-04-01

    : relationships between Chad and neighbouring basins throughout the Mio-Pliocene. Palaeobiogeography, Palaeoclimatology, Palaeoecology, 274 (2009): 134-139. [5] Argyriou T., Otero O., Pavlakis P., Boaz N.T. 2012 - Description and paleobiogeographical implications of new Semlikiichthys (Teleostei, Perciformes) fish material from the Late Miocene deposits of Sahabi, Libya. Geobios, 45(2012): 429-436. [6] Joordens J (Pi) - Coastal origins? A biogeographical model for mominin evolution and dispersal in Africa between 5 and 2.5 million years ago.

  14. Our Magnetic Planet (Arthur Holmes Medal Lecture)

    Science.gov (United States)

    Laj, Carlo

    2015-04-01

    and Turkey) allowed to show that the main post-cretaceous geodynamical evolution of the Aegean Realm is dominated since 30 My by two phases of rotational deformation in opposite sense around two poles: one just north of Albania for the western part, the second in the South Eastern Mediterranean for the eastern part. During the sampling of Mio-Pliocene marls in Crete, using a LETI portable magnetometer to the development of which I have participated, we sampled a geomagnetic reversal registered over about 50 cm of sediments. Interestingly, some intermediate directions were clearly apparent. This gave me the idea that the dynamical directional behaviour of the reversing field could be studied. At the time, only a very few and very incomplete similar records existed. For me, this has been the beginning of an extraordinary adventure still going on today. From the accumulation of data, first from Crete, then from other worldwide spread sites, it became apparent, as illustrated in a cover of Nature, that sedimentary reversal transition paths had a tendency to coincide with the seismically cold deep regions, suggesting that a lower mantle control existed over the reversing geodynamo. This idea, sometimes greeted with scepticism, has stimulated joint efforts to test it both from different disciplines and different experimental and theoretical approaches. It is fair to say that 25 years after it was proposed, our idea is still "on the table" and discussed. We then turned to the study of the changes of the geomagnetic field intensity, still inadequately described at the time. Because measurements of traditional small cubic samples was largely too time consuming to allow surveys of the amplitude we had in mind, I adapted the u-channel measurement techniques to small access pass-through cryogenic magnetometers, and suggested to W. Goree of 2G-Enterprises a modification of the standard pick-up coil geometry (called the Laj-system by the manufacturer) to allow high spatial

  15. Revised age estimates of Australopithecus-bearing deposits at Sterkfontein, South Africa.

    Science.gov (United States)

    Berger, Lee R; Lacruz, Rodrigo; De Ruiter, Darryl J

    2002-10-01

    The Sterkfontein fossil site in South Africa has produced the largest concentration of early hominin fossils from a single locality. Recent reports suggest that Australopithecus from this site is found within a broad paleontological age of between 2.5-3.5 Ma (Partridge [2000] The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 100-125; Partridge et al. [2000a], The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 129-130; Kuman and Clarke [2000] J Hum Evol 38:827-847). Specifically, the hominin fossil commonly referred to as the "Little Foot" skeleton from Member 2, which is arguably the most complete early hominin skeleton yet discovered, has been magnetostratigraphically dated to 3.30-3.33 Ma (Partridge [2000] The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 100-125; Partridge et al. [2000a], The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 129-130). More recent claims suggest that hominin fossils from the Jacovec Cavern are even older, being dated to approximately 3.5 Ma. Our interpretation of the fauna, the archeometric results, and the magnetostratigraphy of Sterkfontein indicate that it is unlikely that any Members yet described from Sterkfontein are in excess of 3.04 Ma in age. We estimate that Member 2, including the Little Foot skeleton, is younger than 3.0 Ma, and that Member 4, previously dated to between 2.4-2.8 Ma, is more likely to fall between 1.5-2.5 Ma. Our results suggest that Australopithecus africanus should not be considered as a temporal contemporary of Australopithecus afarensis, Australopithecus bahrelghazali, and Kenyanthropus platyops. Copyright 2002 Wiley-Liss, Inc.

  16. Patterns of dental development in Homo, Australopithecus, Pan, and Gorilla.

    Science.gov (United States)

    Smith, B H

    1994-07-01

    Smith ([1986] Nature 323:327-330) distinguished patterns of development of teeth of juvenile fossil hominids as being "more like humans" or "more like apes" based on statistical similarity to group standards. Here, this central tendency discrimination (CTD) is tested for its ability to recognize ape and human patterns of dental development in 789 subadult hominoids. Tooth development of a modern human sample (665 black southern Africans) was scored entirely by an outside investigator; pongid and fossil hominid samples (59 Pan, 50 Gorilla, and 14 fossil hominids) were scored by the author. The claim of Lampl et al. ([1993] Am. J. Phys. Anthropol. 90:113-127) that Smith's 1986 method succeeds in only 8% of human cases was not sustained. Figures for overall success of classification (87% humans, 68% apes) mask important effects of teeth sampled and age class. For humans, the power of CTD varied between 53% and 92% depending on the number and kind of teeth available--nearly that of a coin toss when data described only two nearby teeth, but quite successful with more teeth or distant teeth. For apes, only age class affected accuracy: "Infant" apes (M1 development or = root 1/4), however, were correctly discriminated in 87% of cases. Overall, CTD can be considered reliable (accuracy of 92% for humans and 88% for apes) when data contrast development of distant dental fields and subjects are juveniles (not infants). Restricting analysis of fossils to specimens satisfying these criteria, patterns of dental development of gracile australopithecines and Homo habilis remain classified with African apes. Those of Homo erectus and Neanderthals are classified with humans, suggesting that patterns of growth evolved substantially in the Hominidae. To standardize future research, the computer program that operationalizes CTD is now available.

  17. Evolution of life history and behavior in Hominidae: towards phylogenetic reconstruction of the chimpanzee-human last common ancestor.

    Science.gov (United States)

    Duda, Pavel; Zrzavý, Jan

    2013-10-01

    The origin of the fundamental behavioral differences between humans and our closest living relatives is one of the central issues of evolutionary anthropology. The prominent, chimpanzee-based referential model of early hominin behavior has recently been challenged on the basis of broad multispecies comparisons and newly discovered fossil evidence. Here, we argue that while behavioral data on extant great apes are extremely relevant for reconstruction of ancestral behaviors, these behaviors should be reconstructed trait by trait using formal phylogenetic methods. Using the widely accepted hominoid phylogenetic tree, we perform a series of character optimization analyses using 65 selected life-history and behavioral characters for all extant hominid species. This analysis allows us to reconstruct the character states of the last common ancestors of Hominoidea, Hominidae, and the chimpanzee-human last common ancestor. Our analyses demonstrate that many fundamental behavioral and life-history attributes of hominids (including humans) are evidently ancient and likely inherited from the common ancestor of all hominids. However, numerous behaviors present in extant great apes represent their own terminal autapomorphies (both uniquely derived and homoplastic). Any evolutionary model that uses a single extant species to explain behavioral evolution of early hominins is therefore of limited use. In contrast, phylogenetic reconstruction of ancestral states is able to provide a detailed suite of behavioral, ecological and life-history characters for each hypothetical ancestor. The living great apes therefore play an important role for the confident identification of the traits found in the chimpanzee-human last common ancestor, some of which are likely to represent behaviors of the fossil hominins. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Fossil evidence for the origin of Homo sapiens.

    Science.gov (United States)

    Schwartz, Jeffrey H; Tattersall, Ian

    2010-01-01

    Our species Homo sapiens has never received a satisfactory morphological definition. Deriving partly from Linnaeus's exhortation simply to "know thyself," and partly from the insistence by advocates of the Evolutionary Synthesis in the mid-20th Century that species are constantly transforming ephemera that by definition cannot be pinned down by morphology, this unfortunate situation has led to huge uncertainty over which hominid fossils ought to be included in H. sapiens, and even over which of them should be qualified as "archaic" or as "anatomically modern," a debate that is an oddity in the broader context of paleontology. Here, we propose a suite of features that seems to characterize all H. sapiens alive today, and we review the fossil evidence in light of those features, paying particular attention to the bipartite brow and the "chin" as examples of how, given the continuum from developmentally regulated genes to adult morphology, we might consider features preserved in fossil specimens in a comparative analysis that includes extant taxa. We also suggest that this perspective on the origination of novelty, which has gained a substantial foothold in the general field of evolutionary developmental biology, has an intellectual place in paleoanthropology and hominid systematics, including in defining our species, H. sapiens. Beginning solely with the distinctive living species reveals a startling variety in morphologies among late middle and late Pleistocene hominids, none of which can be plausibly attributed to H. sapiens/H. neanderthalensis admixture. Allowing for a slightly greater envelope of variation than exists today, basic "modern" morphology seems to have appeared significantly earlier in time than the first stirrings of the modern symbolic cognitive system. Copyright © 2010 Wiley-Liss, Inc.

  19. The Functional Anatomy of the Carpometacarpal Complex in Anthropoids and Its Implications for the Evolution of the Hominoid Hand.

    Science.gov (United States)

    Selby, Michael S; Simpson, Scott W; Lovejoy, C Owen

    2016-05-01

    Previously, we described several features of the carpometacarpal joints in extant large-bodied apes that are likely adaptations to the functional demands of vertical climbing and suspension. We observed that all hominids, including modern humans and the 4.4-million-year-old hominid Ardipithecus ramidus, lacked these features. Here, we assess the uniqueness of these features in a large sample of monkey, ape, and human hands. These new data provide additional insights into the functional adaptations and evolution of the anthropoid hand. Our survey highlights a series of anatomical adaptations that restrict motion between the second and third metacarpals (MC2 and MC3) and their associated carpals in extant apes, achieved via joint reorganization and novel energy dissipation mechanisms. Their hamate-MC4 and -MC5 joint surface morphologies suggest limited mobility, at least in Pan. Gibbons and spider monkeys have several characters (angled MC3, complex capitate-MC3 joint topography, variably present capitate-MC3 ligaments) that suggest functional convergence in response to suspensory locomotion. Baboons have carpometacarpal morphology suggesting flexion/extension at these joints beyond that observed in most other Old World monkeys, probably as an energy dissipating mechanism minimizing collision forces during terrestrial locomotion. All hominids lack these specializations of the extant great apes, suggesting that vertical climbing was never a central feature of our ancestral locomotor repertoire. Furthermore, the reinforced carpometacarpus of vertically climbing African apes was likely appropriated for knuckle-walking in concert with other novel potential energy dissipating mechanisms. The most parsimonious explanation of the structural similarity of these carpometacarpal specializations in great apes is that they evolved independently. © 2016 Wiley Periodicals, Inc.

  20. Biometrical studies upon hominoid teeth: the coefficient of variation, sexual dimorphism and questions of phylogenetic relationship.

    Science.gov (United States)

    Blumenberg, B

    1985-01-01

    Sexual dimorphism as a function of variation in hominoid tooth metrics has been investigated for four groups of taxa: Recent great apes (two subfamilies), Dryopiths (one subfamily), Ramapiths (one subfamily) and hominids (one family). Gorilla, and to a lesser extent Pan, appear characterized by very high levels of sexual dimorphism and meet several criteria for statistical outliers. Recent great apes are the only group exhibiting consistently high levels of sexual dimorphism. Ramapiths are the only group characterized by low levels of sexual dimorphism and their relative canine length is most similar to Dryopiths. Both Dryopiths and hominids contain taxa with low and intermediate levels of sexual dimorphism. The Gingerich and Shoeninger hypothesis relating coefficients of variation to occlusal complexity is supported. Non-parametric statistics suggest that homogeneity of coefficient of variation profiles over most of the tooth row is characteristic of only the Dryopiths and a composite data set composed of the Dryopith plus Ramapith tooth measurements. Oxnard's model for the multifactorial basis of multiple sexual dimorphisms is also supported. The Dryopith and hominid patterns of sexual dimorphism are similar, an observation that suggests phylogenetic relationship. At the taxonomic level of subfamily or family, sexual dimorphism is a character of cladistic usefulness and possible phylogenetic valence. Assuming that breeding system and sexual dimorphism are functional correlates as many workers suggest, then Ramapithecus sp. China, Sivapithecus indicus and possibly Australopithecus boisei are good candidates for having possessed monogamous breeding/social structures. All Dryopith taxa, S. sivalensis, Sivapithecus sp. China, A. afarensis, Homo habilis and H. erectus emerge as the best candidates for having possessed a polygynous breeding/social structure. No biometrical affinities of Ramapiths with hominids can be demonstrated and some phylogenetic relationship with

  1. Damage and repair of ancient DNA

    DEFF Research Database (Denmark)

    Mitchell, David; Willerslev, Eske; Hansen, Anders

    2005-01-01

    Under certain conditions small amounts of DNA can survive for long periods of time and can be used as polymerase chain reaction (PCR) substrates for the study of phylogenetic relationships and population genetics of extinct plants and animals, including hominids. Because of extensive DNA...... such as extinct horses, cave bears, the marsupial wolf, the moa, and Neanderthal. In the past few years, this technology has been extended to the study of infectious disease in ancient Egyptian and South American mummies, the dietary habits of ancient animals, and agricultural practices and population dynamics...

  2. Religionshistorie og aksetid

    DEFF Research Database (Denmark)

    Jensen, Hans Jørgen Lundager

    2011-01-01

    in the science of religion, Bellah’s model, especially in its combination with recent approaches to the ‘axial age’ and to Merlin Donald’s biocultural cognitive model for hominid evolution, is recommended as a useful starting point for the revitalization of an honorable branch of religious studies. Dansk resume......English summary: The article presents and discusses two articles by Robert Bellah, “Religious evolution” from 1964 and “What is Axial about the Axial Age?” (2005). In what seems to be a general lack of interest in a history of religion (different from a history of religions) among academic scholars...

  3. Neutron Imaging in Cultural Heritage Research at the FRM II Reactor of the Heinz Maier-Leibnitz Center

    Directory of Open Access Journals (Sweden)

    Burkhard Schillinger

    2018-01-01

    Full Text Available Neutron Imaging is ideally suited for applications in cultural heritage even at small reactors with moderate image resolution. However, recently, high resolution imaging is being increasingly used for advanced studies, especially in paleontology. The special contrast for hydrogen and between neighboring elements in the periodic system allows for new applications that are not accessible for X-rays, like organic material in enclosed containers made of ceramics or metals, fossilized bones in chalk rock or in ferrous “red” beds, and even for animal and hominid teeth. Fission neutrons permit the examination of large samples that otherwise show large attenuation for thermal neutrons.

  4. Brains, tools, innovation and biogeography in crows and ravens

    DEFF Research Database (Denmark)

    Jønsson, Knud Andreas; Fabre, Pierre-Henri Fréderic; Irestedt, Martin

    2012-01-01

    BACKGROUND:Crows and ravens (Passeriformes: Corvus) are large-brained birds with enhanced cognitive abilities relative to other birds. They are among the few non-hominid organisms on Earth to be considered intelligent and well-known examples exist of several crow species having evolved innovative...... alone does not explain tool use, innovative feeding strategies and dispersal success within crows.CONCLUSIONS:Our study supports monophyly of the genus Corvus and further demonstrates the direction and timing of colonization from the area of origin in the Palaearctic to other continents and archipelagos...

  5. Deep trophoblast invasion and spiral artery remodelling in the placental bed of the lowland gorilla

    DEFF Research Database (Denmark)

    Pijnenborg, R; Vercruysse, L; Carter, Anthony Michael

    2011-01-01

    in the chimpanzee, we postulated the occurrence of deep invasion in gorilla pregnancy. Tissues were processed for histology (PAS, orcein), lectin staining (Ulex europaeus agglutinin 1) and immunohistochemistry (cytokeratin 7/17, α-actin). A specimen of young but undetermined gestational age included deep placental...... intramural trophoblast. Absence of inner myometrial tissue precluded assessment of invasion depth in this later specimen. Despite the limited material we can conclude that key aspects of trophoblast invasion are shared by the three hominid species: gorilla, chimpanzee and human....

  6. Fossilization Type of Elephas Hysudrindicus From Blora on the Basis of Petrographic and Scanning Electron Microscopic Analyses

    OpenAIRE

    Herman, Danny Z

    2011-01-01

    DOI: 10.17014/ijog.v6i2.117Either fossils of the hominid or vertebrate have long been known from terraces along the Solo River in Central and East Java. Most terraces consist of andesitic sand to andesitic tuffaceous sand with either gravelpebble or conglomerate and some of them contain vertebrate fossils. It is in this place, an ancient elephant fossil named Elephas hysudrindicus was discovered in 2009. This fossil was discovered at an abandoned sand quarry of Sunggun area, Medalem Village, ...

  7. Skeletal adaptations to bipedalism

    Directory of Open Access Journals (Sweden)

    Vasiljević Perica

    2014-01-01

    Full Text Available Bipedalism is the main characteristic of humans. During evolutin bipedalism emerged probably as an adaptation to a changing environment. Major changes in skeletal system included femur, pelvis, skull and spine. The significance of bipedal locomotion: Bipedalism freed the forelimbs for carrying objects, creation and usage of tools. In the upright position animals have a broader view of the environment and the early detection of predators is crucial for survival. Bipedal locomotion makes larger distances easier to pass, which is very important in the migration of hominids.

  8. Species, genera, and phylogenetic structure in the human fossil record: a modest proposal.

    Science.gov (United States)

    Tattersall, Ian

    2017-05-01

    Because of the greater morphological distances among them, genera should be more robustly recognizable in the fossil record than species are. But there are clearly upper as well as lower bounds to their species inclusivity. Currently, the vast majority of fossils composing the large and rapidly expanding paleoanthropological record are crammed into one of two genera (Australopithecus vs Homo), expanding the latter, especially, far beyond any reasonable morphological or phylogenetic limits. This excessive inclusivity obscures both diversity and the complexities of phylogenetic structure within the hominid family. © 2017 Wiley Periodicals, Inc.

  9. Buccal dental microwear variability in extant African Hominoidea: taxonomy versus ecology.

    Science.gov (United States)

    Galbany, Jordi; Estebaranz, Ferran; Martínez, Laura M; Pérez-Pérez, Alejandro

    2009-07-01

    Buccal microwear patterns on teeth are good indicators of the abrasiveness of foodstuffs and have been used to trace the dietary habits of fossil species, including primates and hominids. However, few studies have addressed the variability of this microwear. The abrasiveness of dietary components depends not only on the hardness of the particles ingested, but also on the presence of dust and other exogenous elements introduced during food processing. These elements are responsible for the microwear typology observed on the enamel surfaces of primate teeth. Here we analyzed the variability of buccal microwear patterns in African Great Apes (Gorilla gorilla and Pan troglodytes), using tooth molds obtained from the original specimens held in several osteological collections. Our results suggest that ecological adaptations at subspecies or population level account for differences in microwear patterns, which are attributed to habitat and ecological conditions within populations rather than differences between species. The findings from studies on the variability of buccal dental microwear in extant species will contribute to a better understanding of extinct hominids' diet and ecology.

  10. The Mobile Element Locator Tool (MELT): population-scale mobile element discovery and biology

    Science.gov (United States)

    Gardner, Eugene J.; Lam, Vincent K.; Harris, Daniel N.; Chuang, Nelson T.; Scott, Emma C.; Pittard, W. Stephen; Mills, Ryan E.; Devine, Scott E.

    2017-01-01

    Mobile element insertions (MEIs) represent ∼25% of all structural variants in human genomes. Moreover, when they disrupt genes, MEIs can influence human traits and diseases. Therefore, MEIs should be fully discovered along with other forms of genetic variation in whole genome sequencing (WGS) projects involving population genetics, human diseases, and clinical genomics. Here, we describe the Mobile Element Locator Tool (MELT), which was developed as part of the 1000 Genomes Project to perform MEI discovery on a population scale. Using both Illumina WGS data and simulations, we demonstrate that MELT outperforms existing MEI discovery tools in terms of speed, scalability, specificity, and sensitivity, while also detecting a broader spectrum of MEI-associated features. Several run modes were developed to perform MEI discovery on local and cloud systems. In addition to using MELT to discover MEIs in modern humans as part of the 1000 Genomes Project, we also used it to discover MEIs in chimpanzees and ancient (Neanderthal and Denisovan) hominids. We detected diverse patterns of MEI stratification across these populations that likely were caused by (1) diverse rates of MEI production from source elements, (2) diverse patterns of MEI inheritance, and (3) the introgression of ancient MEIs into modern human genomes. Overall, our study provides the most comprehensive map of MEIs to date spanning chimpanzees, ancient hominids, and modern humans and reveals new aspects of MEI biology in these lineages. We also demonstrate that MELT is a robust platform for MEI discovery and analysis in a variety of experimental settings. PMID:28855259

  11. Accelerated evolution of the ASPM gene controlling brain size begins prior to human brain expansion.

    Directory of Open Access Journals (Sweden)

    Natalay Kouprina

    2004-05-01

    Full Text Available Primary microcephaly (MCPH is a neurodevelopmental disorder characterized by global reduction in cerebral cortical volume. The microcephalic brain has a volume comparable to that of early hominids, raising the possibility that some MCPH genes may have been evolutionary targets in the expansion of the cerebral cortex in mammals and especially primates. Mutations in ASPM, which encodes the human homologue of a fly protein essential for spindle function, are the most common known cause of MCPH. Here we have isolated large genomic clones containing the complete ASPM gene, including promoter regions and introns, from chimpanzee, gorilla, orangutan, and rhesus macaque by transformation-associated recombination cloning in yeast. We have sequenced these clones and show that whereas much of the sequence of ASPM is substantially conserved among primates, specific segments are subject to high Ka/Ks ratios (nonsynonymous/synonymous DNA changes consistent with strong positive selection for evolutionary change. The ASPM gene sequence shows accelerated evolution in the African hominoid clade, and this precedes hominid brain expansion by several million years. Gorilla and human lineages show particularly accelerated evolution in the IQ domain of ASPM. Moreover, ASPM regions under positive selection in primates are also the most highly diverged regions between primates and nonprimate mammals. We report the first direct application of TAR cloning technology to the study of human evolution. Our data suggest that evolutionary selection of specific segments of the ASPM sequence strongly relates to differences in cerebral cortical size.

  12. Spain's magic mountain: narrating prehistory at Atapuerca.

    Science.gov (United States)

    Hochadel, Oliver

    2016-09-01

    The Sierra de Atapuerca in northern Spain is ranked among the most important excavation sites in human origins research worldwide. The project boasts not only spectacular hominid fossils, among them the 'oldest European', but also a fully fledged 'popularization industry'. This article interprets this multimedia industry as a generator of different narratives about the researchers as well as about the prehistoric hominids of Atapuerca. It focuses on the popular works of the three co-directors of the project. Juan Luis Arsuaga, José María Bermúdez de Castro and Eudald Carbonell make deliberate use of a variety of narrative devices, resonant cultural references and strategies of scientific self-commodification. All three, in different ways, use the history of science and of their own research project to mark their place in the field of human origins research, drawing on mythical elements to tell the story of the rise of a humble Spanish team overcoming all odds to achieve universal acclaim. Furthermore, the co-directors make skilful use of palaeofiction - that of Björn Kurtén and Jean Auel, as well as writing their own - in order to tell gripping stories about compassion and solidarity in human prehistory. This mixture of nationalist and universalist narratives invites the Spanish audience to identify not just with 'their ancestors' but also with the scientists, as objects and subjects of research become conflated through popularization.

  13. Aural exostoses (surfer's ear) provide vital fossil evidence of an aquatic phase in Man's early evolution.

    Science.gov (United States)

    Rhys Evans, P H; Cameron, M

    2017-11-01

    For over a century, otolaryngologists have recognised the condition of aural exostoses, but their significance and aetiology remains obscure, although they tend to be associated with frequent swimming and cold water immersion of the auditory canal. The fact that this condition is usually bilateral is predictable since both ears are immersed in water. However, why do exostoses only grow in swimmers and why do they grow in the deep bony meatus at two or three constant sites? Furthermore, from an evolutionary point of view, what is or was the purpose and function of these rather incongruous protrusions? In recent decades, paleoanthropological evidence has challenged ideas about early hominid evolution. In 1992 the senior author suggested that aural exostoses were evolved in early hominid Man for protection of the delicate tympanic membrane during swimming and diving by narrowing the ear canal in a similar fashion to other semiaquatic species. We now provide evidence for this theory and propose an aetiological explanation for the formation of exostoses.

  14. Stone tool function at the paleolithic sites of Starosele and Buran Kaya III, Crimea: behavioral implications.

    Science.gov (United States)

    Hardy, B L; Kay, M; Marks, A E; Monigal, K

    2001-09-11

    Stone tools are often the most abundant type of cultural remains at Paleolithic sites, yet their function is often poorly understood. Investigations of stone tool function, including microscopic use-wear and residue analyses, were performed on a sample of artifacts from the Paleolithic sites of Starosele (40,000-80,000 years BP) and Buran Kaya III (32,000-37,000 years BP). The Middle Paleolithic levels at Starosele exhibit a typical variant of the local Micoquian Industry. The artifacts from Buran Kaya III most closely resemble an Early Streletskayan Industry associated with the early Upper Paleolithic. The results of the functional analyses suggest that hominids at both sites were exploiting woody and starchy plant material as well as birds and mammals. Both sites show evidence of hafting of a wide variety of tools and the possible use of projectile or thrusting spears. These analyses were performed by using two different techniques conducted by independent researchers. Combined residue and use-wear analyses suggest that both the Upper Paleolithic and Middle Paleolithic hominids at these sites were broad-based foragers capable of exploiting a wide range of resources.

  15. First occurrence of early Homo in the Nachukui Formation (West Turkana, Kenya) at 2.3-2.4 Myr.

    Science.gov (United States)

    Prat, Sandrine; Brugal, Jean-Philip; Tiercelin, Jean-Jacques; Barrat, Jean-Alix; Bohn, Marcel; Delagnes, Anne; Harmand, Sonia; Kimeu, Kamoya; Kibunjia, Mzalendo; Texier, Pierre-Jean; Roche, Hélène

    2005-08-01

    Cognitive abilities and techno-economic behaviours of hominids in the time period between 2.6-2.3 Myr have become increasingly well-documented. This time period corresponds to the oldest evidence for stone tools at Gona (Kada Gona, West Gona, EG 10-12, OGS 6-7), Hadar (AL 666), lower Omo valley (Ftji1, 2 & 5, Omo 57, Omo 123) in Ethiopia, and West Turkana (Lokalalei sites -LA1 & LA2C-) in Kenya. In 2002 a new palaeoanthropological site (LA1alpha), 100 meters south of the LA1 archaeological site, produced a first right lower molar of a juvenile hominid (KNM-WT 42718). The relative small size of the crown, its marked MD elongation and BL reduction, the relative position of the cusps, the lack of a C6 and the mild expression of a protostylid, reinforced by metrical analyses, demonstrate the distinctiveness of this tooth compared with Australopithecus afarensis, A. anamensis, A. africanus and Paranthropus boisei, and its similarity to early Homo. The LA1alpha site lies 2.2 m above the Ekalalei Tuff which is slightly younger than Tuff F dated to 2.34+/-0.04 Myr. This juvenile specimen represents the oldest occurrence of the genus Homo in West Turkana.

  16. Sédimentation et tectonique dans le bassin marin Eocène supérieur-Oligocène des Alpes du Sud Sedimentation and Tectonics in the Upper Eocene-Oligocene Marine Basin in the Southern Alps

    Directory of Open Access Journals (Sweden)

    Riche P.

    2006-11-01

    'exprime nettement moins que précédemment. Le toit des grès est marqué par une surface de discontinuité fortement érosive correspondant à des canyons sous-marins de direction NE-SO. Cette surface peut être mise en relation avec l'écoulement des olistostromes qui termine le remplissage du bassin. La mise en place de ces olistostromes et des olistolithes qui les accompagnent n'est pas paléontologiquement datée : elle débute avec la fin de la sédimentation gréseuse. L'ensemble est encore affecté par une distension E-O ce qui tend à montrer que cette mise en place est antérieure à la phase de serrage miocène. La confrontation entre les observations de terrain, les expériences de sédimentation en canal et l'interprétation sismique de bassins offshore argumente les interprétations proposées. This paper is based on local field surveys performed recently by Institut Français du Pétrole (IFP and Ecole Nationale Supérieure du Pétrole et des Moteurs (ENSPM in the western part of the southern Alps nummulitic basin, to help interpret seismic data. It underlines the role of extensional tectonics during sedimentation. It questions the geodynamic interpretation of the basin as a foredeep basin in the Alpine orogenic belt. On a Mesozoic basement folded by the Pyreneo-Provençale orogeny, as early as the Lutetian the nummulitic transgression flooded the eastern area, which was subsequently obscured by the Pennine main fault during Mio-Pliocene times. It spread westward during the Upper Eocene. In the meantime, an E-W extension, shown clearly along the Var River faults and along the edge of the Pelvoux range, fragmented the fringes of the basin with blocks tilted during sedimentation. The result is fast changes of facies within the basal carbonates, which pass from platform types to slope types and to thin gravitational sediments farther into the basin. The overlying marls correspond to slope facies wrapping the inherited topography. The Gres d'Annot s. l

  17. Quantum Field Theory in Curved Spacetime

    Science.gov (United States)

    Reynolds, Sally C.; Gallagher, Andrew

    2012-03-01

    List of contributors; Foreword J. T. Francis Thackeray; 1. African genesis: an evolving paradigm Sally C. Reynolds; 2. Academic genealogy Peter Ungar and Phillip V. Tobias; Part I. In Search of Origins: Evolutionary Theory, New Species, and Paths into the Past: 3. Speciation in hominin evolution Colin Groves; 4. Searching for a new paradigm for hominid origins in Chad (Central Africa) Michel Brunet; 5. From hominoid arboreality to hominid bipedalism Brigitte Senut; 6. Orrorin and the African ape/hominid dichotomy Martin Pickford; 7. A brief history and results of 40 years of Sterkfontein excavations Ronald J. Clarke; Part II. Hominin Morphology Through Time: Brains, Bodies and Teeth: 8. Hominin brain evolution, 1925-2011: an emerging overview Dean Falk; 9. The issue of brain reorganisation in Australopithecus and early hominids: Dart had it right Ralph L. Holloway; 10. The mass of the human brain: is it a spandrel? Paul R. Manger, Jason Hemingway, Muhammad Spocter and Andrew Gallagher; 11. Origin and diversity of early hominin bipedalism Henry M. McHenry; 12. Forelimb adaptations in Australopithecus afarensis Michelle S. M. Drapeau; 13. Hominin proximal femur morphology from the Tugen Hills to Flores Brian G. Richmond and William L. Jungers; 14. Daily rates of dentine formation and root extension rates in Paranthropus boisei, KNM-ER 1817, from Koobi Fora, Kenya M. Christopher Dean; 15. On the evolutionary development of early hominid molar teeth and the Gondolin Paranthropus molar Kevin L. Kuykendall; 16. Digital South African fossils: morphological studies using reference-based reconstruction and electronic preparation Gerhard W. Weber, Philipp Gunz, Simon Neubauer, Philipp Mitteroecker and Fred L. Bookstein; Part III. Modern Human Origins: Patterns, and Processes: 17. Body size in African Middle Pleistocene Homo Steven E. Churchill, Lee R. Berger, Adam Hartstone-Rose and Headman Zondo; 18. The African origin of recent humanity Milford H. Wolpoff and Sang-Hee Lee

  18. The 'big bang' theory of the origin of psychosis and the faculty of language.

    Science.gov (United States)

    Crow, Timothy J

    2008-07-01

    To achieve a unified concept of the aetiology of psychosis. The nuclear symptoms of "schizophrenia" occur with approximately the same age- and sex-specific incidence in all human populations. No substantive environmental precipitant has been identified, and yet these "illnesses" are associated with deviations in brain structure that are uniform across populations, are established late in development and relate to the capacity for language. No genes have been identified by linkage or association strategies. It is postulated that the variation 1. relates precisely to the genetic mechanism that distinguishes the species Homo sapiens from its precursor. 2. constitutes a class of epigenetic diversity intrinsic to the genetic control of the species characteristic (the "specific mate recognition system" according to the theory of HEH Paterson). 3. reflects the role of the cerebral torque in the neuro-developmental re-organization that enabled the faculty of language. A genetic mechanism involving both the X and the Y chromosomes is suggested by 1) evidence for anomalies of asymmetry of brain structure and function in the sex chromosome aneuploidies, 2) a same sex concordance effect for handedness, 3) sex differences in lateralization, and verbal and spatial ability, and their inter-relationships. These three facts direct attention to the Xq21.3/Yp11.2 homology block that was established by an X to Y duplication 6 million years ago, ie at the time of origin of the hominid lineage. Within this block a gene pair (Protocadherin11X and Y) expressed as two cell surface adhesion molecules at axo-dendritic synapses has been subject to change (16 amino-acid substitutions in the Y, and critically 5 in the X sequence) in the hominid lineage. The X to Y duplication and its subsequent modification (4 deletions and a paracentric inversion) on the Y may have played a central role in hominid speciation with the most recent change (at around 160,000 years) representing the transition to

  19. The role of tephra studies in African paleoanthropology as exemplified by the Sidi Hakoma Tuff

    Science.gov (United States)

    WoldeGabriel, Giday; Endale, Tamrat; White, Tim D.; Thouveny, Nicolas; Hart, William K.; Renne, Paul R.; Asfaw, Berhane

    2013-01-01

    Beginning in the 1960s, geological and paleoanthropological exploration of the Ethiopian rift system's basins have led to the discovery and assembly of the most comprehensive record of human biological and technological change during the last 6 million years. The hominid fossils, including partial skeletons, were primarily discovered in the Afar Rift, the Main Ethiopian Rift, and in the Omo Basin of the broadly rifted zone of SW Ethiopia. The paleoanthropological research areas within the SW Afar Rift that have yielded many diverse hominid species and the oldest stone tools are, from north to south, Woranso-Mille (aff. Ardipithecus and Au. afarensis), Hadar (Au. afarensis, Homo sp.), Dikika (Au. afarensis), Gona (Ar. kadabba, Ar. ramidus, H. erectus, and oldest stone tools), Middle Awash (Ar. kadabba, Ar. ramidus, Au. anamensis, Au. afarensis, Au. garhi, H. erectus, H. rhodesiensis, H. sapiens idaltu, and the oldest paleo-butchery locality), and Galili (Au. afarensis). Additional hominid remains were discovered at Melka Kunture on the banks of the Awash River near its source along the western margin of the central part of the Main Ethiopian Rift (H. erectus), at Konso (H. erectus and A. boisei), and at the southern end of the MER, and in the Omo Basin (Au. anamensis, Au. afarensis, Au. aethiopicus, Au. boisei, H. habilis, and H. erectus). Distal and sometimes proximal tephra units interbedded within fossilifeous sedimentary deposits have become key elements in this work by providing chronological and correlative control and depositional contexts. Several regional tephra markers have been identified within the northern half of the eastern African rift valley in Ethiopia and Kenya, and in marine sediments of the Gulf of Aden Rift and the NW Indian Ocean. Out of the many regional tephra stratigraphic markers that range in age from the early Pliocene (3.97 Ma) to the late Pleistocene (0.16 Ma), the Sidi Hakoma Tuff (SHT) has been more widely identified and thoroughly

  20. Environmental availability, behavioural diversity and diet: a zooarchaeological approach from the TD10-1 sublevel of Gran Dolina (Sierra de Atapuerca, Burgos, Spain) and Bolomor Cave (Valencia, Spain)

    Science.gov (United States)

    Blasco, Ruth; Rosell, Jordi; Fernández Peris, Josep; Arsuaga, Juan Luis; Bermúdez de Castro, José María; Carbonell, Eudald

    2013-06-01

    The suggestion that the Neanderthal linage hominids had predominantly rich diet in meat derived from large game is progressing towards views which propose a higher nutritional diversity, at least in some regions. These postulates situate hominids as the knower of their natural surroundings and make them capable of selecting within the range of resources available in their landscapes. Using a zooarchaeological approach, the taxonomical representation in an anthropogenic site could indicate both the environment diversity that human groups can exploit and the decisions that they make when selecting prey. The Optimal Foraging theory is a basic decision model that is ideally applied within a larger framework of constraining conditions such as differential prey distributions, food-consumer imbalances and/or competition, among others. Nevertheless, if this theory is applied to human behaviour, uncontrolled variables could exist and substantially alter some predictions. These variables may not always be related to the need to optimise the resources; additionally, they can respond to the questions related to nutritional ecology, cultural standards or social relationships conditioned by ecological or technological factors. Environmental and socio-cultural aspects invite us to reflect on the characteristics that delimit the pre-Upper Palaeolithic diet and its correct assessment in relation to the availability of prey in the environment and the human behavioural parameters. In this study, we present data from several levels of Bolomor Cave (Valencia, Spain, MIS 9-5e) and a sample from the TD10-1 sublevel of Gran Dolina (Sierra de Atapuerca, Burgos, Spain, MIS 9). Both sites have been interpreted as habitat places and allow us to infer the high plasticity of human groups with respect to methods and techniques of acquisition and use of a diverse spectrum of prey. Environmental availability, duration and type of settlement seem to significantly influence the taxonomical

  1. Music as a technology for social bonding: Comment on "Music, empathy, and cultural understanding" by E. Clarke et al.

    Science.gov (United States)

    Launay, Jacques

    2015-12-01

    From the perspective of evolutionary psychology music can be seen as problematic. Despite its ubiquity there is still no clearly agreed function in terms of improving the fitness of the species. Is it therefore fairer to judge it as 'auditory cheesecake' (see [1]) rather than attributing it with any specific purpose? An alternative argument is that it plays a fundamental role in the formation of human social bonds, and the authors of ;Music, empathy, and cultural understanding; concur with the view that music has a unique capacity to help people connect with others [2]. There is now evidence that even in the modern world there is a significant effect of our social bonds on health and longevity [3], suggesting that our hominid ancestors might have relied heavily on their social network for survival. If music has the capacity to encourage the formation of these social bonds it could form a powerful tool in the success of our species.

  2. Sergey Vladimirovich Vasilyev is 50!

    Directory of Open Access Journals (Sweden)

    Gerasimova Margarita M.

    2013-09-01

    Full Text Available Colleagues congratulate Sergey Vladimirovich Vasilyev, head, Department of physical anthropology of the Institute of Ethnology and Anthropology, Russian Academy of Sciences, Doctor of Historical Sciences, on his 50th birth anniversary. The data on his biography and current scientific and organizational activities are provided. S. V. Vasilyev has proved himself as an expert in a wide scale of problems; he has conducted research in a variety of fields: from ethology of primates and morphology of the earliest hominids to the variability in the framework of different contemporary human communities, including problems of genetics and the possibility of identifying the remains of historical figures. He considers himself a disciple of Ya. Ya. Roginsky and A. A. Zubov. Of recent, the sphere of S.V. Vasilyev’s special attention has included the study of the craniology of medieval population of the European part of Russia. He has authored 11 monographs and over 150 articles on anthropology and paleoanthropology.

  3. Limits of spatial vision in Sumatran orangutans (Pongo abelii.

    Directory of Open Access Journals (Sweden)

    Laura C. Adams

    2017-08-01

    Full Text Available Although research with animals is often done under the assumption that visual abilities are similar across species, the visual ability of most animals, including orangutans, has not been experimentally evaluated. In this study we assessed the contrast sensitivity function (CSF of two female zoo-housed Sumatran orangutans (Pongo abelii aged 20 and 26 years old. Orangutans were rewarded for selecting vertical or horizontal square wave gratings at the correct orientation. Results showed a CSF similar in shape and position to that of human adults, although with lower contrast sensitivity. These lower values may be due to testing constraints or may be due to species differences. These data have implications for research on orangutan cognition, hominid evolution, and have practical implications for captive and wild management of this endangered species.

  4. The Impact of Evolutionary Driving Forces on Human Complex Diseases: A Population Genetics Approach

    Directory of Open Access Journals (Sweden)

    Amr T. M. Saeb

    2016-01-01

    Full Text Available Investigating the molecular evolution of human genome has paved the way to understand genetic adaptation of humans to the environmental changes and corresponding complex diseases. In this review, we discussed the historical origin of genetic diversity among human populations, the evolutionary driving forces that can affect genetic diversity among populations, and the effects of human movement into new environments and gene flow on population genetic diversity. Furthermore, we presented the role of natural selection on genetic diversity and complex diseases. Then we reviewed the disadvantageous consequences of historical selection events in modern time and their relation to the development of complex diseases. In addition, we discussed the effect of consanguinity on the incidence of complex diseases in human populations. Finally, we presented the latest information about the role of ancient genes acquired from interbreeding with ancient hominids in the development of complex diseases.

  5. The history of African trypanosomiasis

    Directory of Open Access Journals (Sweden)

    Steverding Dietmar

    2008-02-01

    Full Text Available Abstract The prehistory of African trypanosomiasis indicates that the disease may have been an important selective factor in the evolution of hominids. Ancient history and medieval history reveal that African trypanosomiasis affected the lives of people living in sub-Saharan African at all times. Modern history of African trypanosomiasis revolves around the identification of the causative agents and the mode of transmission of the infection, and the development of drugs for treatment and methods for control of the disease. From the recent history of sleeping sickness we can learn that the disease can be controlled but probably not be eradicated. Current history of human African trypanosomiasis has shown that the production of anti-sleeping sickness drugs is not always guaranteed, and therefore, new, better and cheaper drugs are urgently required.

  6. Two possible driving forces supporting the evolution of animal communication. Comment on "Towards a Computational Comparative Neuroprimatology: Framing the language-ready brain" by Michael A. Arbib

    Science.gov (United States)

    Moulin-Frier, Clément; Verschure, Paul F. M. J.

    2016-03-01

    In the target paper [1], M.A. Arbib proposes a quite exhaustive review of the (often computational) models developed during the last decades that support his detailed scenario on language evolution (the Mirror System Hypothesis, MSH). The approach considers that language evolved from a mirror system for grasping already present in LCA-m (the last common ancestor of macaques and humans), to a simple imitation system for grasping present in LCA-c (the last common ancestor of chimpanzees and humans), to a complex imitation system for grasping that developed in the hominid line since that ancestor. MSH considers that this complex imitation system is a key evolutionary step for a language-ready brain, providing all the required elements for an open-ended gestural communication system. The transition from the gestural (bracchio-manual and visual) to the vocal (articulatory and auditory) domain is supposed to be a less important evolutionary step.

  7. A tentative framework for the acquisition of language and modern human cognition.

    Science.gov (United States)

    Tattersall, Ian

    2016-06-20

    Modern human beings process information symbolically, rearranging mental symbols to envision multiple potential realities. They also express the ideas they form using structured articulate language. No other living creature does either of these things. Yet it is evident that we are descended from a non-symbolic and non-linguistic ancestor. How did this astonishing transformation occur? Scrutiny of the fossil and archaeological records reveals that the transition to symbolic reasoning happened very late in hominid history - indeed, within the tenure of anatomically recognizable Homo sapiens. It was evidently not simply a passive result of the increase in brain size that typified multiple lineages of the genus Homo over the Pleistocene. Instead, a brain exaptively capable of complex symbolic manipulation and language acquisition was acquired in the major developmental reorganization that gave rise to the anatomically distinctive species Homo sapiens. The new capacity it conferred was later recruited through the action of a cultural stimulus, most plausibly the spontaneous invention of language.

  8. Reflections on the Schön affair

    Science.gov (United States)

    Brandon, David; Santic, Branko

    2009-07-01

    In her feature article on the fraud perpetrated by Jan Hendrik Schön (May pp24-29), Eugenie Samuel Reich concludes that the fake data Schön generated at Bell Labs were designed primarily to meet the expectations of his peers. She is probably right, but the Schön case was by no means the first of its kind. A century ago the Piltdown fraud, in which medieval cranial fragments were matched with part of an orang-utan jaw bone, convinced British archaeologists and palaeontologists that early hominids developed on the South Downs. The scientific evidence was never fully accepted outside the British Empire, but it still took the UK's Natural History Museum 50 years to recognize the hoax. "Piltdown man" was created to meet the expectations of the British archaeological community, and hence the fraud succeeded.

  9. Genome wide analyses reveal little evidence for adaptive evolution in many plant species.

    Science.gov (United States)

    Gossmann, Toni I; Song, Bao-Hua; Windsor, Aaron J; Mitchell-Olds, Thomas; Dixon, Christopher J; Kapralov, Maxim V; Filatov, Dmitry A; Eyre-Walker, Adam

    2010-08-01

    The relative contribution of advantageous and neutral mutations to the evolutionary process is a central problem in evolutionary biology. Current estimates suggest that whereas Drosophila, mice, and bacteria have undergone extensive adaptive evolution, hominids show little or no evidence of adaptive evolution in protein-coding sequences. This may be a consequence of differences in effective population size. To study the matter further, we have investigated whether plants show evidence of adaptive evolution using an extension of the McDonald-Kreitman test that explicitly models slightly deleterious mutations by estimating the distribution of fitness effects of new mutations. We apply this method to data from nine pairs of species. Altogether more than 2,400 loci with an average length of approximately 280 nucleotides were analyzed. We observe very similar results in all species; we find little evidence of adaptive amino acid substitution in any comparison except sunflowers. This may be because many plant species have modest effective population sizes.

  10. Ontogenetic study of the supraorbital region in modern humans: a longitudinal test of the spatial model.

    Science.gov (United States)

    Fiscella, Gabriela N; Smith, Fred H

    2006-06-01

    The structural significance of the hominid supraorbital torus and its morphological variation have always been a controversial topic in physical anthropology. Understanding the function of browridge variation in living and fossil human populations is relevant to questions of human evolution. This study utilizes radiograph images to evaluate the spatial model in modern humans during ontogeny. This structural model attributes variation in the supraorbital region to the positional relationship between the neurocranium and the orbits. The relationship between measurements of the antero-posterior supraorbital length and the factors specified in the spatial model were assessed by correlation and partial correlation analyses. Growth rates were also examined to study ontogenetic trajectories and infer aspects of developmental relationships between critical variables. Results agree with previous research supporting the existence of spatial influences between the neural and orbital-upper facial regions on browridge length during ontogeny.

  11. Genetic, physiologic and ecogeographic factors contributing to variation in Homo sapiens: Homo floresiensis reconsidered.

    Science.gov (United States)

    Richards, Gary D

    2006-11-01

    A new species, Homo floresiensis, was recently named for Pleistocene hominid remains on Flores, Indonesia. Significant controversy has arisen regarding this species. To address controversial issues and refocus investigations, I examine the affinities of these remains with Homo sapiens. Clarification of problematic issues is sought through an integration of genetic and physiological data on brain ontogeny and evolution. Clarification of the taxonomic value of various 'primitive' traits is possible given these data. Based on this evidence and using a H. sapiens morphological template, models are developed to account for the combination of features displayed in the Flores fossils. Given this overview, I find substantial support for the hypothesis that the remains represent a variant of H. sapiens possessing a combined growth hormone-insulin-like growth factor I axis modification and mutation of the MCPH gene family. Further work will be required to determine the extent to which this variant characterized the population.

  12. Actions speak louder than words in socially foraging human groups.

    Science.gov (United States)

    Sumner, Seirian; King, Andrew J

    2011-11-01

    SOCIAL FORAGING IN HUMANS HAS A DEEP EVOLUTIONARY HISTORY: early hominids searched for dispersed food sources in a patchy, uncertain environment. A fundamental assumption is that social foragers benefit by exchanging information about food sources, in order to make collective decisions based on pooled information. We conducted the first experimental test of this assumption, and showed that, as predicted, communication significantly enhanced group performance. A further, unexpected result was that physical communication through gesturing, rather than verbal communication, appeared to play a crucial role in the early stages of group interaction, facilitating consensus decision making by groups.  The importance of gestures in human interactions may therefore be underestimated, and this has important implications for modern human societies, where communications are becoming increasingly dominated by virtual modes of communication that preclude the use of gestures. 

  13. Three new human skulls from the Sima de los Huesos Middle Pleistocene site in Sierra de Atapuerca, Spain.

    Science.gov (United States)

    Arsuaga, J L; Martínez, I; Gracia, A; Carretero, J M; Carbonell, E

    1993-04-08

    Three important fossil hominids were found in July 1992 in the Middle Pleistocene cave site called Sima de los Huesos (Sierra de Atapuerca, Burgos, Northern Spain). One is a complete calvaria (cranium 4), the second a virtually complete cranium (cranium 5), the third represents a more fragmentary cranium of an immature individual (cranium 6). There is a large difference in size between the two adult specimens (for example endocranial volume 1,125 cm3 versus 1,390 cm3). The Atapuerca human remains are dated to > 300,000 years. The Atapuerca cranial sample fits within the 'archaic Homo sapiens' group, but is well differentiated from the Asian Homo erectus group. The extensive Atapuerca human collection is the most complete sample of Middle Pleistocene humans yet discovered from one site, and appears to document an early stage in Neanderthal evolution.

  14. A complete human pelvis from the Middle Pleistocene of Spain.

    Science.gov (United States)

    Arsuaga, J L; Lorenzo, C; Carretero, J M; Gracia, A; Martínez, I; García, N; Bermúdez de Castro, J M; Carbonell, E

    1999-05-20

    The Middle Pleistocene site of Sima de los Huesos in Sierra de Atapuerca, Spain, has yielded around 2,500 fossils from at least 33 different hominid individuals. These have been dated at more than 200,000 years ago and have been classified as ancestors of Neanderthals. An almost complete human male pelvis (labelled Pelvis 1) has been found, which we associate with two fragmentary femora. Pelvis 1 is robust and very broad with a very long superior pubic ramus, marked iliac flare, and a long femoral neck. This pattern is probably the primitive condition from which modern humans departed. A modern human newborn would pass through the birth canal of Pelvis 1 and this would be even larger in a female individual. We estimate the body mass of this individual at 95 kg or more. Using the cranial capacities of three specimens from Sima de los Huesos, the encephalization quotients are substantially smaller than in Neanderthals and modern humans.

  15. Geochronology: age of Mexican ash with alleged 'footprints'.

    Science.gov (United States)

    Renne, Paul R; Feinberg, Joshua M; Waters, Michael R; Arroyo-Cabrales, Joaquin; Ochoa-Castillo, Patricia; Perez-Campa, Mario; Knight, Kim B

    2005-12-01

    A report of human footprints preserved in 40,000-year-old volcanic ash near Puebla, Mexico (http://www.royalsoc.ac.uk/exhibit.asp?id=3616&tip=1), was the subject of a press conference that stirred international media attention. If the claims (http://www.mexicanfootprints.co.uk) of Gonzalez et al. are valid, prevailing theories about the timing of human migration into the Americas would need significant revision. Here we show by 40Ar/39Ar dating and corroborating palaeomagnetic data that the basaltic tuff on which the purported footprints are found is 1.30+/-0.03 million years old. We conclude that either hominid migration into the Americas occurred very much earlier than previously believed, or that the features in question were not made by humans on recently erupted ash.

  16. The Paleo-Anthropocene and the Genesis of the Current Landscape of Israel

    Directory of Open Access Journals (Sweden)

    Ackermann Oren

    2017-12-01

    Full Text Available Worldwide, human impact on natural landscapes has intensified since prehistoric times, and this is well documented in the global archaeological record. The period between the earliest hominids and the Industrial Revolution of the late 18-19th centuries is known as the Paleo-Anthropocene. The current study reviews key geoarchaeological, floral and faunal factors of the Paleo-Anthropocene in Israel, an area that has undergone human activities in various intensities since prehistoric times. It discusses significant human imprints on these three features in the Israeli landscape, demonstrating that its current form is almost entirely anthropogenic. Moreover, some of the past physical changes still dynamically shape Israel’s zoological, archaeological and geomorphic landscape today. It is hoped that insights from this article might aid in guiding present-day management strategies of undeveloped areas through renewal of human activity guided by traditional knowledge.

  17. Paleoparasitology: the origin of human parasites

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    Adauto Araujo

    2013-09-01

    Full Text Available Parasitism is composed by three subsystems: the parasite, the host, and the environment. There are no organisms that cannot be parasitized. The relationship between a parasite and its host species most of the time do not result in damage or disease to the host. However, in a parasitic disease the presence of a given parasite is always necessary, at least in a given moment of the infection. Some parasite species that infect humans were inherited from pre-hominids, and were shared with other phylogenetically close host species, but other parasite species were acquired from the environment as humans evolved. Human migration spread inherited parasites throughout the globe. To recover and trace the origin and evolution of infectious diseases, paleoparasitology was created. Paleoparasitology is the study of parasites in ancient material, which provided new information on the evolution, paleoepidemiology, ecology and phylogenetics of infectious diseases.

  18. Human Uniqueness, Cognition by Description, and Procedural Memory

    Directory of Open Access Journals (Sweden)

    John Bolender

    2008-06-01

    Full Text Available Evidence will be reviewed suggesting a fairly direct link between the human ability to think about entities which one has never perceived — here called “cognition by description” — and procedural memory. Cognition by description is a uniquely hominid trait which makes religion, science, and history possible. It is hypothesized that cognition by description (in the manner of Bertrand Russell’s “knowledge by description” requires variable binding, which in turn utilizes quantifier raising. Quantifier raising plausibly depends upon the computational core of language, specifically the element of it which Noam Chomsky calls “internal Merge”. Internal Merge produces hierarchical structures by means of a memory of derivational steps, a process plausibly involving procedural memory. The hypothesis is testable, predicting that procedural memory deficits will be accompanied by impairments in cognition by description. We also discuss neural mechanisms plausibly underlying procedural memory and also, by our hypothesis, cognition by description.

  19. Cultural Evolutionary Perspectives on Creativity and Human Innovation.

    Science.gov (United States)

    Fogarty, Laurel; Creanza, Nicole; Feldman, Marcus W

    2015-12-01

    Cultural traits originate through creative or innovative processes, which might be crucial to understanding how culture evolves and accumulates. However, because of its complexity and apparent subjectivity, creativity has remained largely unexplored as the dynamic underpinning of cultural evolution. Here, we explore the approach to innovation commonly taken in theoretical studies of cultural evolution and discuss its limitations. Drawing insights from cognitive science, psychology, archeology, and even animal behavior, it is possible to generate a formal description of creativity and to incorporate a dynamic theory of creativity into models of cultural evolution. We discuss the implications of such models for our understanding of the archaeological record and the history of hominid culture. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. The topology of hair streams and whorls in man, with an observation on their relationship to epidermal ridge patterns.

    Science.gov (United States)

    Findlay, G H; Harris, W F

    1977-05-01

    Hair slope, whorl, cross and field formation is expressible in a topological form. The mathematical description required suggests an origin for the patterns in a growth process occurring in the upper dermis which determines the patterns of the hair slope. The formulae proposed by Euler, Poincaré and Ludwig are adopted as a descriptive method for the analysis of hair patterning resulting from hair slope. A unitary theory for hair streams and fingerprint patterns is suggested by the discovery, on one remarkable human foetus, of sites where epidermal ridges and convergent hair whorls were combined. Placement of the parietal scalp whorl in man is linked to hominid brain and skull development, and its associated hair field is noted to be bipartite, as revealed through patterns of differential hair loss.

  1. Throwing behavior and mass distribution of stone selection in tufted capuchin monkeys (Cebus apella).

    Science.gov (United States)

    Cleveland, A; Rocca, A R; Wendt, E L; Westergaard, G C

    2003-12-01

    Cannell [Journal of Archaeological Science 29:335-339, 2002] argued that sex-based differences among humans in terms of the mass of chosen throwing stones could be used to infer body mass and patterns of sexual dimorphism in early hominids from Olduvai and Koobi Fora by examining the mass distributions of unaltered stone tools at those sites. We examined this hypothesis in tufted capuchin monkeys using a comparative approach, by investigating the relationships among body mass, sex, stone weight preference, and accuracy in a throwing task. The subject sample consisted of nine monkeys trained to perform an aimed-throwing task in which a food reward could be obtained by throwing a stone into a bucket. We found that 1) the subjects showed a strong mean stone mass preference; 2) the females chose heavier stones than the males, in terms of absolute mean selected stone mass and selected stone mass relative to body mass; 3) subjects threw more accurately when they used stones of preferred mass vs. stones of nonpreferred mass; and 4) overall, the males were more accurate in the throwing task than the females. We conclude that capuchins are highly selective when choosing throwing stones, and that this confers an advantage for throwing accuracy. Our results indicate that the sexually dimorphic pattern in stone mass preference observed among humans does not generalize to Cebus apella. We suggest that researchers examining this pattern in humans in an attempt to explain early hominid patterns of dimorphism and behavior should take into account not only stone weight preference, but also its adaptive advantage. Copyright 2003 Wiley-Liss, Inc.

  2. The effect of lower limb length on the energetic cost of locomotion: implications for fossil hominins.

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    Steudel-Numbers, Karen L; Tilkens, Michael J

    2004-01-01

    The consequences of the relatively short lower limbs characteristic of AL 288-1 have been widely discussed, as have the causes and consequences of the short limbs of Neanderthals. Previous studies of the effect of limb length on the energetic cost of locomotion have reported no relationship; however, limb length could have accounted for as much as 19% of the variation in cost and gone undetected (Steudel and Beattie, 1995; Steudel, 1994, 1996). Kramer (1999) and Kramer and Eck (2000) have recently used a theoretical model to predict the effect of the shorter limbs of early hominids, concluding that the shorter limbs may actually have been energetically advantageous. Here, we took an experimental approach. Twenty-one human subjects, of varying limb lengths, walked on a treadmill at 2.6, 2.8, 3.0 and 3.2m.p.h., while their expired gases were analyzed. The subjects walked for 12 minutes at each speed and their rates of oxygen consumption (VO2) over four minutes were averaged to estimate VO2. We also measured each subject's height, weight and lower limb length. Lean body mass and % fat were determined using dual-energy x-ray absorptiometry. ANCOVA with total VO2 at either speed as the dependent variable and total lean mass, % fat and lower limb length as covariates resulted in all three covariates having a significant positive effect on VO2 at p<0.01. Subjects with relatively longer lower limbs had lower locomotor costs. Thus the short lower limbs characteristic of some hominid taxa would have resulted in more costly locomotion, barring some physiological anomaly. The magnitude of this effect is substantial; Neanderthals are estimated to have had locomotor costs 30% greater than those of contemporary anatomically modern humans. By contrast the increase in lower limb length seen in H. erectus would have mitigated the increase in locomotor costs produced by the increase in body size.

  3. Dating the Naisiusiu Beds, Olduvai Gorge, by electron spin resonance

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    Skinner, A. R.; Hay, R. L.; Masao, F.; Blackwell, B. A. B.

    2003-05-01

    The lower beds at Olduvai Gorge are well known for containing early hominid fossils and Oldowan stone tools, and their ages have been established by 40Ar/ 39Ar dating and paleomagnetic stratigraphy. Ages are generally less certain for the upper deposits at Olduvai Gorge because of the scarcity of datable tuffs. The youngest archaeologically significant site at Olduvai is microlithic LSA, which lies in the type section of the Naisiusiu Beds. The age for the site is controversial, with 14C dates of 17,000-17,550 (Hay, R.L., 1976 Geology of Olduvai Gorge, University of California Press, Berkeley) and >42,000 BP (Manega, P.C., 1993. Geochronology, geochemistry, and isotopic study of the Plio-Pleistocene Hominid sites and the Ngorongoro Volcanic Highland in Northern Tanzania. Unpublished Ph.D. Thesis, University of Colorado, Boulder, CO). The tuff bed in the zone with artifacts does not contain materials datable by 40Ar/ 39Ar, and some other dating method was needed. In the summer of 2001, five equid teeth were collected from the type Naisiusiu site. Another tooth had previously been collected. ESR ages have been determined for three teeth from the archaeological level and their ages cluster around 62±5 ka, assuming linear uranium uptake. Another tooth from a level without artifacts and believed to be significantly younger dated to 39±5 ka, again assuming LU. These dates are considerably older than previous estimates and suggest that the East African MSA/LSA transition occurred very early.

  4. Game-Changing Innovations: How Culture Can Change the Parameters of Its Own Evolution and Induce Abrupt Cultural Shifts.

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    Oren Kolodny

    2016-12-01

    Full Text Available One of the most puzzling features of the prehistoric record of hominid stone tools is its apparent punctuation: it consists of abrupt bursts of dramatic change that separate long periods of largely unchanging technology. Within each such period, small punctuated cultural modifications take place. Punctuation on multiple timescales and magnitudes is also found in cultural trajectories from historical times. To explain these sharp cultural bursts, researchers invoke such external factors as sudden environmental change, rapid cognitive or morphological change in the hominids that created the tools, or replacement of one species or population by another. Here we propose a dynamic model of cultural evolution that accommodates empirical observations: without invoking external factors, it gives rise to a pattern of rare, dramatic cultural bursts, interspersed by more frequent, smaller, punctuated cultural modifications. Our model includes interdependent innovation processes that occur at different rates. It also incorporates a realistic aspect of cultural evolution: cultural innovations, such as those that increase food availability or that affect cultural transmission, can change the parameters that affect cultural evolution, thereby altering the population's cultural dynamics and steady state. This steady state can be regarded as a cultural carrying capacity. These parameter-changing cultural innovations occur very rarely, but whenever one occurs, it triggers a dramatic shift towards a new cultural steady state. The smaller and more frequent punctuated cultural changes, on the other hand, are brought about by innovations that spur the invention of further, related, technology, and which occur regardless of whether the population is near its cultural steady state. Our model suggests that common interpretations of cultural shifts as evidence of biological change, for example the appearance of behaviorally modern humans, may be unwarranted.

  5. Tortoises as a dietary supplement: A view from the Middle Pleistocene site of Qesem Cave, Israel

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    Blasco, Ruth; Rosell, Jordi; Smith, Krister T.; Maul, Lutz Christian; Sañudo, Pablo; Barkai, Ran; Gopher, Avi

    2016-02-01

    Dietary reconstructions can offer an improved perspective on human capacities of adaptation to the environment. New methodological approaches and analytical techniques have led to a theoretical framework for understanding how human groups used and adapted to their local environment. Faunal remains provide an important potential source of dietary information and allow study of behavioural variation and its evolutionary significance. Interest in determining how hominids filled the gaps in large prey availability with small game or what role small game played in pre-Upper Palaeolithic societies is an area of active research. Some of this work has focused on tortoises because they represent an important combination of edible and non-edible resources that are easy to collect if available. The exploitation of these slow-moving animals features prominently in prey choice models because the low handling costs of these reptiles make up for their small body size. Here, we present new taphonomic data from two tortoise assemblages extracted from the lower sequence of the Middle Pleistocene site of Qesem Cave, Israel (420-300 ka), with the aim of assessing the socio-economic factors that may have led to the inclusion of this type of resource in the human diets. We show that hominid damage on large tortoise specimens from Qesem Cave is not unusual and that evidence such as cut marks, percussion marks and consistent patterns of burning suggests established sequences of processing, including cooking in the shell, defleshing, and direct percussion to access the visceral content. These matters make it possible not only to assess the potential role of tortoises as prey, but also to evaluate collecting behaviour in the resource acquisition systems and eco-social strategies at the Acheulo-Yabrudian Cultural Complex (AYCC) in the southern Levant.

  6. Creativity as a Determinant of the Development of Homo Sapiens

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    Alexander G. Kruglov

    2016-12-01

    Full Text Available This work was undertaken to determine the genesis and role of creativity (Cr in the formation of mental qualities that gave Homo sapiens (HS the evolutionary advantages in intra- and interspecific competition during the period of the intraspecific bifurcation of hominids on the border of the Middle and Upper Paleolithic. Creativity allowed HS to design the adaptive forms of purposeful behavior corresponding to the conditions and the degree of uncertainty, and create stable mental constructs, in the absence of perceptual sources, that do not require reactive behavior. Visualization of a target image, which originally had an applied and instructional value in the process of semantic filling, was transformed into a symbol, which, getting the qualities of the perceptual source, loses its connection to the primary value and initiates the creation of qualitatively new needs for hominids: bilateral (direct and inverse relations in the system "subject-symbol." The ability to produce the prognostic hypothesis with expansion of the operating range of the HS mind allowed the ability to search and change the tactics of an adaptive behavior, which gave the results: improvements in quality of life and an increase in life expectancy (genetically fixed; domination in intra- and interspecific competition; the emergence of new operating systems of the psyche, including the emergence and development of symbolic thought. As a criterion of creativity, with the potential ability for quantitative measurement, we propose the value of deviation of creative oscillations ("proposal" of a creative individual from the boundaries between stereotypes: for the cognition sphere, a deviation from the border between recognizable and unrecognizable; for the social sphere, between acceptable and unacceptable.

  7. Developmental identity versus typology: Lucy has only four sacral segments.

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    Machnicki, Allison L; Lovejoy, C Owen; Reno, Philip L

    2016-08-01

    Both interspecific and intraspecific variation in vertebral counts reflect the action of patterning control mechanisms such as Hox. The preserved A.L. 288-1 ("Lucy") sacrum contains five fused elements. However, the transverse processes of the most caudal element do not contact those of the segment immediately craniad to it, leaving incomplete sacral foramina on both sides. This conforms to the traditional definition of four-segmented sacra, which are very rare in humans and African apes. It was recently suggested that fossilization damage precludes interpretation of this specimen and that additional sacral-like features of its last segment (e.g., the extent of the sacral hiatus) suggest a general Australopithecus pattern of five sacral vertebrae. We provide updated descriptions of the original Lucy sacrum. We evaluate sacral/coccygeal variation in a large sample of extant hominoids and place it within the context of developmental variation in the mammalian vertebral column. We report that fossilization damage did not shorten the transverse processes of the fifth segment of Lucy's sacrum. In addition, we find that the extent of the sacral hiatus is too variable in apes and hominids to provide meaningful information on segment identity. Most importantly, a combination of sacral and coccygeal features is to be expected in vertebrae at regional boundaries. The sacral/caudal boundary appears to be displaced cranially in early hominids relative to extant African apes and humans, a condition consistent with the likely ancestral condition for Miocene hominoids. While not definitive in itself, a four-segmented sacrum accords well with the "long-back" model for the Pan/Homo last common ancestor. Am J Phys Anthropol 160:729-739, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  8. Taxonomic identification of Lower Pleistocene fossil hominins based on distal humeral diaphyseal cross-sectional shape

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    Michael R. Lague

    2015-07-01

    Full Text Available The coexistence of multiple hominin species during the Lower Pleistocene has long presented a challenge for taxonomic attribution of isolated postcrania. Although fossil humeri are well-suited for studies of hominin postcranial variation due to their relative abundance, humeral articular morphology has thus far been of limited value for differentiating Paranthropus from Homo. On the other hand, distal humeral diaphyseal shape has been used to justify such generic distinctions at Swartkrans. The potential utility of humeral diaphyseal shape merits larger-scale quantitative analysis, particularly as it permits the inclusion of fragmentary specimens lacking articular morphology. This study analyzes shape variation of the distal humeral diaphysis among fossil hominins (c. 2-1 Ma to test the hypothesis that specimens can be divided into distinct morphotypes. Coordinate landmarks were placed on 3D laser scans to quantify cross-sectional shape at a standardized location of the humeral diaphysis (proximal to the olecranon fossa for a variety of fossil hominins and extant hominids. The fossil sample includes specimens attributed to species based on associated craniodental remains. Mantel tests of matrix correlation were used to assess hypotheses about morphometric relationships among the fossils by comparing empirically-derived Procrustes distance matrices to hypothetical model matrices. Diaphyseal shape variation is consistent with the hypothesis of three distinct morphotypes (Paranthropus, Homo erectus, non-erectus early Homo in both eastern and southern Africa during the observed time period. Specimens attributed to non-erectus early Homo are unique among hominids with respect to the degree of relative anteroposterior flattening, while H. erectus humeri exhibit morphology more similar to that of modern humans. In both geographic regions, Paranthropus is characterized by a morphology that is intermediate with respect to those morphological features

  9. Should autism be considered a canary bird telling that Homo sapiens may be on its way to extinction?

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    Olav Albert Christophersen

    2012-08-01

    Full Text Available There has been a dramatic enhancement of the reported incidence of autism in different parts of the world over the last 30 years. This can apparently not be explained only as a result of improved diagnosis and reporting, but may also reflect a real change. The causes of this change are unknown, but if we shall follow T.C. Chamberlin's principle of multiple working hypotheses, we need to take into consideration the possibility that it partly may reflect an enhancement of the average frequency of responsible alleles in large populations. If this hypothesis is correct, it means that the average germline mutation rate must now be much higher in the populations concerned, compared with the natural mutation rate in hominid ancestors before the agricultural and industrial revolutions. This is compatible with the high prevalence of impaired human semen quality in several countries and also with what is known about high levels of total exposure to several different unnatural chemical mutagens, plus some natural ones at unnaturally high levels. Moreover, dietary deficiency conditions that may lead to enhancement of mutation rates are also very widespread, affecting billions of people. However, the natural mutation rate in hominids has been found to be so high that there is apparently no tolerance for further enhancement of the germline mutation rate before the Eigen error threshold will be exceeded and our species will go extinct because of mutational meltdown. This threat, if real, should be considered far more serious than any disease causing the death only of individual patients. It should therefore be considered the first and highest priority of the best biomedical scientists in the world, of research-funding agencies and of all medical doctors to try to stop the express train carrying all humankind as passengers on board before it arrives at the end station of our civilization.

  10. Evolutionary and functional significance of hominoid tooth enamel.

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    Gantt, D G; Rafter, J A

    1998-01-01

    The purpose of this investigation is to evaluate enamel thickness in extant and extinct hominoids. The material used in this study spans the evolutionary history of this group, from 20 million years ago to the present. The objectives of this investigation are to test three hypotheses: (1) the Loading Hypothesis: loading areas of the crown have thicker enamel than non-loading areas; (2) the Phyletic Hypothesis: differences in enamel thickness provide a basis for determining evolutionary relationships; and (3) the Functional Hypothesis: differences among hominoids result from adaptations to differing dietary and ecological habitats, that is from folivory to frugivory to hard object feeding and from tropical to forest to savanna habitats. Thin sections were prepared and polished to approximately 100 microm in thickness. Each section was then enlarged and digitally captured to the computer. Image processing and analysis software, SigmaImage (was used to measure the sections. Subsequent statistical analysis was conducted with SigmaStat and SPSS statistical software programs. The data provides statistical support for all hypotheses. In particular, the data support the proposal that "thick" enamel is the ancestral condition for the great apes and human clade. Therefore, Pongo would have retained its enamel thickness from the common ancestor of the great apes and Gorilla and Pan would have secondarily reduced enamel thickness to "thin." The common ancestor of the hominids, the australopithecines, would have "thick" enamel. The "hyper-thick" enamel of the australopithecines would be a derived character for this clade due to increased crushing and grinding and adaptation to savanna habitat. Homo would have secondarily reduced enamel thickness to "thick." Evolutionary biology of enamel differs markedly in hominids from that found in other hominoids and primates. Increased enamel thickness involved both increases in absolute thickness of enamel and crown size in response to

  11. A systematic reassessment and paleogeographic review of fossil xenarthra from Peru

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    2004-01-01

    exclusivamente andino presentando formas de tamaño pequeño, cuadrupedos y con tendencia a pastar perteneciente al subgénero M. (Pseudomegatherium e incluye a M. (P. tarijensis, M. (P. elenense, M. (P. urbinai y una nueva especie de la zona norandina. Las grandes especies de perezosos como M. (Megatherium americanum, Lestodon sp., y Scelidotherium leptocephalum descubiertos en las Pampas Argentinas no han sido reportados en el Perú. Un nuevo megaloníquido muy peculiar fue descubierto en la costa norte (desierto de Cupisnique y en los Andes, cerca al lago Titicaca (cueva casa del diablo. Dataciones relizadas con 14C, así como la asociación faunística indican que la mayoría de los mamíferos fósiles del Perú pertenecen al Lujanense. A lo largo de la costa y probablemente en la Amazonía, los Xenarthra han sido descubiertos en localidades abiertas, en contraste con la región andina donde la mayor parte de los especímenes se conservaron en cuevas. En el Perú y en toda Sudamérica los grandes Xenartros se extinguen al comienzo del Holoceno. A revision of Peruvian Xenarthra and the discovery of new specimens have increased our knowledge of the Order in this country. About thirty sites from three geographic regions, Amazonian Forest, the Andes, and the coast have yielded Xenarthra in Peru. The only well known Pre-Pleistocene Xenarthra is Thalassocnus from the Mio-Pliocene of the Pisco Formation. Pleistocene Phyllophaga (Megatheriidae, Nothrotheriidae, Mylodontidae, and Megalonychidae and Cingulata (Pampatheriidae and Glyptodontidae are rare in the Amazonian forest region, abundant in the coastal region and are particularly frequent in the Andes (between 2 500 and 4 500 meters. Cingulata are not as diverse and are represented only by Holmesina cf. paulacoutoi along the coast and Glyptodon clavipes in the Andes. The mylodontid Glossotherium sp. is recognized in the entire Peruvian coast and the scelidothere Scelidodon chiliensis is abundant in both the Andes and northern

  12. Evidence from facial morphology for similarity of Asian and African representatives of Homo erectus.

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    Rightmire, G P

    1998-05-01

    It has been argued that Homo erectus is a species confined to Asia. Specialized characters displayed by the Indonesian and Chinese skulls are said to be absent in material from eastern Africa, and individuals from Koobi Fora and Nariokotome are now referred by some workers to H. ergaster. This second species is held to be the ancestor from which later human populations are derived. The claim for two taxa is evaluated here with special reference to the facial skeleton. Asian fossils examined include Sangiran 4 and Sangiran 17, several of the Ngandong crania, Gongwangling, and of course the material from Zhoukoudian described by Weidenreich ([1943] Palaeontol. Sin. [New Ser. D] 10:1-484). African specimens compared are KNM-ER 3733 and KNM-ER 3883 from Koobi Fora and KNM-WT 15000 from Nariokotome. Hominid 9 from Olduvai is useful only insofar as the brows and interorbital pillar are preserved. Neither detailed anatomical comparisons nor measurements bring to light any consistent patterns in facial morphology which set the African hominids apart from Asian H. erectus. Faces of the African individuals do tend to be high and less broad across the orbits. Both of the Koobi Fora crania but not KNM-WT 15000 have nasal bones that are narrow superiorly, while the piriform aperture is relatively wide. In many other characters, including contour of the supraorbital torus, glabellar prominence, nasal bridge dimensions, internasal keeling, anatomy of the nasal sill and floor, development of the canine jugum, orientation of the zygomaticoalveolar pillar, rounding of the anterolateral surface of the cheek, formation of a malar tubercle, and palatal rugosity, there is variation among individuals from localities within the major geographic provinces. Here it is not possible to identify features that are unique to either the Asian or African assemblages. Additional traits such as a forward sloping "crista nasalis," presence of a "sulcus maxillaris," a high (and massive) cheek coupled

  13. Variation and diversity in Homo erectus: a 3D geometric morphometric analysis of the temporal bone.

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    Terhune, Claire E; Kimbel, William H; Lockwood, Charles A

    2007-07-01

    Although the level of taxonomic diversity within the fossil hominin species Homo erectus (sensu lato) is continually debated, there have been relatively few studies aiming to quantify the morphology of this species. Instead, most researchers have relied on qualitative descriptions or the evaluation of nonmetric characters, which in many cases display continuous variation. Also, only a few studies have used quantitative data to formally test hypotheses regarding the taxonomic composition of the "erectus" hypodigm. Despite these previous analyses, however, and perhaps in part due to these varied approaches for assessing variation within specimens typically referred to H. erectus (sensu lato) and the general lack of rigorous statistical testing of how variation within this taxon is partitioned, there is currently little consensus regarding whether this group is a single species, or whether it should instead be split into separate temporal or geographically delimited taxa. In order to evaluate possible explanations for variation within H. erectus, we tested the general hypothesis that variation within the temporal bone morphology of H. erectus is consistent with that of a single species, using great apes and humans as comparative taxa. Eighteen three-dimensional (3D) landmarks of the temporal bone were digitized on a total of 520 extant and fossil hominid crania. Landmarks were registered by Generalized Procrustes Analysis, and Procrustes distances were calculated for comparisons of individuals within and between the extant taxa. Distances between fossil specimens and between a priori groupings of fossils were then compared to the distances calculated within the extant taxa to assess the variation within the H. erectus sample relative to that of known species, subspecies, and populations. Results of these analyses indicate that shape variation within the entire H. erectus sample is generally higher than extant hominid intraspecific variation, and putative H. ergaster

  14. Magnetostratigraphy of the Koobi Fora Formation, Lake Turkana, Kenya

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    Hillhouse, J. W.; Cerling, T. E.; Brown, F. H.

    1986-10-01

    The Koobi Fora Formation, a Pliocene and Pleistocene sequence of sedimentary deposits northeast of Lake Turkana, has yielded numerous fossils and stone artifacts of early hominids. Stratigraphic correlation of the hominid-bearing deposits throughout the Turkana region was established primarily by the chemistry and isotopic ages of volcanic tuffs and complemented by magnetostratigraphic studies. We have reinterpreted previously published magnetostratigraphy from the upper part of the Koobi Fora Formation because the original stratigraphy and dating of tuffs have been revised. In our reinterpretation we include previously unpublished data from the uppermost part of the formation. The upper magnetozones correlate with parts of the Brunhes Normal-Polarity Chron and Matuyama Reversed-Polarity Chron (about 0.6-0.85 Ma) and are separated from the magnetozones of the upper part of the Matuyama (2.0-1.25 Ma) by a disconformity. The Olduvai Normal-Polarity Subchron is represented within the Matuyama, but the lower part of the Matuyama (2.4-2.0 Ma) is missing due to an erosional disconformity. We have also determined magnetozones in the lower part of the Koobi Fora Formation, which had not been sampled for paleomagnetism during the earlier studies. Our time calibration of the magnetozones is made possible by isotopic dating of several tuffs and by chemical correlation of Koobi Fora tuffs with dated tuffs in the Shungura Formation of southern Ethiopia. The tephra correlations are corroborated by the excellent concordance between the magnetostratigraphies of the Koobi Fora and Shungura formations. The lower part of the Koobi Fora spans the interval from about 4 Ma to 2.4 Ma, within the Gilbert Reversed-Polarity and Gauss Normal-Polarity chrons. Rock magnetic studies indicate that detrital magnetite carries most of the stable remanence, although hematite contributes to the remanence as indicated by thermal demagnetization. The hematite, which presumably formed by

  15. From monkey-like action recognition to human language: an evolutionary framework for neurolinguistics.

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    Arbib, Michael A

    2005-04-01

    The article analyzes the neural and functional grounding of language skills as well as their emergence in hominid evolution, hypothesizing stages leading from abilities known to exist in monkeys and apes and presumed to exist in our hominid ancestors right through to modern spoken and signed languages. The starting point is the observation that both premotor area F5 in monkeys and Broca's area in humans contain a "mirror system" active for both execution and observation of manual actions, and that F5 and Broca's area are homologous brain regions. This grounded the mirror system hypothesis of Rizzolatti and Arbib (1998) which offers the mirror system for grasping as a key neural "missing link" between the abilities of our nonhuman ancestors of 20 million years ago and modern human language, with manual gestures rather than a system for vocal communication providing the initial seed for this evolutionary process. The present article, however, goes "beyond the mirror" to offer hypotheses on evolutionary changes within and outside the mirror systems which may have occurred to equip Homo sapiens with a language-ready brain. Crucial to the early stages of this progression is the mirror system for grasping and its extension to permit imitation. Imitation is seen as evolving via a so-called simple system such as that found in chimpanzees (which allows imitation of complex "object-oriented" sequences but only as the result of extensive practice) to a so-called complex system found in humans (which allows rapid imitation even of complex sequences, under appropriate conditions) which supports pantomime. This is hypothesized to have provided the substrate for the development of protosign, a combinatorially open repertoire of manual gestures, which then provides the scaffolding for the emergence of protospeech (which thus owes little to nonhuman vocalizations), with protosign and protospeech then developing in an expanding spiral. It is argued that these stages involve

  16. Can Cooler Heads Prevail?

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    Rice, A. R.

    2015-12-01

    The significant correlation between dropping temperatures throughout the Pliocene and the concomitant explosive expansion of the Hominid brain has led a number of workers to postulate climate change drove human evolution. Our brain (that of Homo sapiens), comprises 1-2 percent of our body weight but consumes 20 -25 percent of the body's caloric intake. We are "hotheads". Brains are extremely sensitive to overheating but we are endowed with unparalleled thermal regulation, much of it given over to protecting the Central Nervous System (CNS). Will there be reversed trends with global warming? The human brain has been shrinking since the end of the Ice Ages, losing about 150cc over the past 10,000 years. Polar bear skulls have been downsizing as well. Almost all mass extinctions or evolutionary upheavals are attributed to global warming: e.g. the Permian/Triassic (P/T) event, i.e., "The Great Dying", 250 million years ago (~90% of all life forms wiped out); the Paleocene/ Eocene Thermal Maximum (PETM) 55 million years ago. They may be analogs for what might await us. Large creatures, whose body size inhibits cooling, melted away during the PETM. Horses, initially the size of dogs then, reduced to the size of cats. An unanticipated hazard for humans that may attend extreme global warming is dumbing down or needing to retreat to the Poles as did those creatures that survived the P/T event (some references: http://johnhawks.net/research/hawks-2011-brain-size-selection-holocene; Kandel, E. et al Principles of Neural Science 4th ed. New York (US): McGraw-Hill, 2000; Selective Brain Cooling in Early Hominids:phylogenetic and evolutionary implications, Reeser, H., reeser@flmnh.ufl.edu; How the body controls brain temperature; the temperature shielding effect of cerebral blood flow, Mingming Z. et al. J Appl Physiol. 2006 November; 101(5): 1481-1488; news.nationalgeographic.com/ news/2014/03/140327-climate-change-shrinks-salamanders-global-warming-science/; Heat illness and

  17. The importance of the nutritive value of old bones in the diet of Bearded vultures Gypaetus barbatus.

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    Margalida, Antoni; Villalba, Daniel

    2017-08-14

    Vultures are central-place foragers and need to optimize their foraging behaviour to offset travel costs by increasing their energy gain. This process is more obvious in certain vulture species that do not feed their young by regurgitation and so must carry food items back to the nest. The Bearded Vulture Gypaetus barbatus is the only species with a bone-diet based. We analysed the chemical composition of bones and the age-related changes in their nutritive value to assess the differences in energy content between bones of differing age, body part and species. We found differences between specific anatomical parts, species and the age of the bones. Fresh bones contain 108% as much energy as fresh meat and, interestingly, dry bones retain 90% of the protein found in fresh bones. Dry femurs weighing 140 g retain enough protein to be comparable to 111 g of fresh meat, in energy terms. Compared to meat-eating species, the specialized osteophagous diet of the Bearded Vulture seems to have certain advantages. A better understanding of nutrient levels in food remains could help to improve theoretical foraging models, assist in conservation management, and even improve our understanding of the use of bones by early hominids.

  18. Ancient origin and gene mosaicism of the progenitor of mycobacteriumtuberculosis.

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    2005-09-01

    Full Text Available The highly successful human pathogen Mycobacterium tuberculosis has an extremely low level of genetic variation, which suggests that the entire population resulted from clonal expansion following an evolutionary bottleneck around 35,000 y ago. Here, we show that this population constitutes just the visible tip of a much broader progenitor species, whose extant representatives are human isolates of tubercle bacilli from East Africa. In these isolates, we detected incongruence among gene phylogenies as well as mosaic gene sequences, whose individual elements are retrieved in classical M. tuberculosis. Therefore, despite its apparent homogeneity, the M. tuberculosis genome appears to be a composite assembly resulting from horizontal gene transfer events predating clonal expansion. The amount of synonymous nucleotide variation in housekeeping genes suggests that tubercle bacilli were contemporaneous with early hominids in East Africa, and have thus been coevolving with their human host much longer than previously thought. These results open novel perspectives for unraveling the molecular bases of M. tuberculosis evolutionary success.

  19. Chemistry and mineralogy of some Plio-Pleistocene tuffs from the Shungura Formation, southwest Ethiopia

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    Martz, A. M.; Brown, F. H.

    1981-09-01

    The Shungura Formation of southwestern Ethiopia has yielded many tens of thousands of vertebrate fossils including hominids and microvertebrates, and in addition has also yielded fossil wood, pollen, and invertebrates. Widespread tuffs have made subdivision and detailed mapping of the formation possible, have provided material for potassium-argon dating, and have allowed direct lithostratigraphic correlation with the Koobi Fora Formation in northern Kenya. The basis for correlation between the two formations is the distinctive chemistry of the tuffs, but systematic chemical variation within some tuffs invalidates some statistical correlation techniques. Here chemical analysis of glass separates and minerals from tuffs of the Shungura and Usno Formations are presented which may allow further ties to be established when data become available on other tuffs of the Koobi Fora Formation. The tuffs consist primarily of glass, but also contain phenocrysts of anorthoclase, hedenbergitic pyroxene, sodic amphibole, ilmenite, titanomagnetite, chevkinite, quartz, zircon, and rarely orthopyroxene and plagioclase. The glasses show evidence of alkali loss during hydration, and are not now peralkaline, although it is likely that they were initially. The source volcanoes were most likely situated within the Ethiopian rift valley, or on its margins.

  20. New Australopithecus boisei calvaria from East Lake Turkana, Kenya.

    Science.gov (United States)

    Brown, B; Walker, A; Ward, C V; Leakey, R E

    1993-06-01

    The calvaria of an adult Australopithecus boisei from Area 104, Koobi Fora, Lake Turkana, is described. The specimen, KNM-ER 23000, comes from sediments dated to about 1.9 Ma. It consists of the frontal, both parietals, both temporals, most of the occipital as well as two small pieces of sphenoid, and a mandibular tooth root. The specimen is presumed to be an adult male, based on its size and the great development of features associated with the masticatory apparatus. KNM-ER 23000 is close in general size and shape to KNM-ER 406, KNM-ER 13750, and Olduvai Hominid 5 and it has a mixture of features seen in these three roughly contemporaneous crania. The frontal, especially the tori, resembles that of OH 5; the parietals are most like those of KNM-ER 13750; the occipital is like those of the two other Turkana specimens, and the temporals have a mixture of features from all of these, This specimen adds to our knowledge of variability in A. boisei.

  1. The Lake Ndutu cranium and early Homo sapiens in Africa.

    Science.gov (United States)

    Rightmire, G P

    1983-06-01

    The partial cranium from Lake Ndutu, near Olduvai Gorge in northern Tanzania, has generally been viewed as Homo erectus, although points of similarity to H. sapiens have also been recognized. Bones of the vault are in fact quite thick, and the cranium is small. Length and breadth dimensions are comparable to those of earlier H. erectus from Koobi Fora and Ileret, and the Ndutu individual is more similar in size to O.H. 12 than to O.H. 9. Unfortunately, the facial skeleton and frontal bone are very incomplete, and little useful information can be obtained from these parts of the existing reconstruction. The parietals are also damaged, but the left temporal is more satisfactorily preserved, and the occiput is nearly complete. Occipital morphology, mastoid shape, and characteristics of the glenoid cavity and tympanic plate probably provide the best available guide to affinities of the Ndutu hominid. In many of these features the cranium resembles Broken Hill, Elandsfontein, and other African fossils referred to archaic H. sapiens. There are some similarities to modern humans also, but no ties to the Neanderthals of Europe. Allocation of Ndutu to an African subspecies of H. sapiens seems most appropriate, even if the pattern of relationships between such archaic populations and recent humans is still unclear.

  2. Procesos de formación de los yacimientos plio-pleistocenicos africanos y su relevancia para los modelos de comportamiento homínido

    Directory of Open Access Journals (Sweden)

    Ignacio de la Torre Sainz

    1999-01-01

    Full Text Available La controversia surgida a principios de los años 80 sobre la naturaleza del registro del Plio-Pleistoceno, ha conducido a un debate aún vigente en torno a los agentes envueltos en la formación de los primeros yacimientos arqueológicos. Algunos autores argüyeron que estos depósitos eran palimpsestos en los que la actividad humana fue marginal, mientras que otros opinan que son el resultado de unas estrategias complejas llevadas a cabo por los primeros representantes del género Homo. En el presente trabajo se hace una valoración crítica de los datos disponibles sobre el registro arqueológico plio-pleistocénico, y se propone el marco conductual que hizo posible la formación de estos primeros yacimientos.The controversy about the formation of the early Piio-Pieistocene archaeological site formation has resulted in a wide array of studies regarding the different processes involved therein. Some authors argüe that early sites were palimpsest where hominid intervention was minimal, whereas other researchers support the idea that sites were referential places used by the earliest representatives of the genus Homo. This paper presents the available evidence supporting either hyphoteses and several behavioral models are critically revised.

  3. Exploring the Potential of Laser Ablation Carbon Isotope Analysis for Examining Ecology during the Ontogeny of Middle Pleistocene Hominins from Sima de los Huesos (Northern Spain)

    Science.gov (United States)

    Garcia, Nuria; Feranec, Robert S.; Passey, Benjamin H.; Cerling, Thure E.; Arsuaga, Juan Luis

    2015-01-01

    Laser ablation of tooth enamel was used to analyze stable carbon isotope compositions of teeth of hominins, red deer, and bears from middle Pleistocene sites in the Sierra de Atapuerca in northern Spain, to investigate the possibility that this technique could be used as an additional tool to identify periods of physiological change that are not detectable as changes in tooth morphology. Most of the specimens were found to have minimal intra-tooth variation in carbon isotopes (< 2.3‰), suggesting isotopically uniform diets through time and revealing no obvious periods of physiological change. However, one of the two sampled hominin teeth displayed a temporal carbon isotope shift (3.2‰) that was significantly greater than observed for co-occurring specimens. The δ13C value of this individual averaged about -16‰ early in life, and -13‰ later in life. This isotopic change occurred on the canine crown about 4.2 mm from the root, which corresponds to an approximate age of two to four years old in modern humans. Our dataset is perforce small owing to the precious nature of hominid teeth, but it demonstrates the potential utility of the intra-tooth isotope profile method for extracting ontogenetic histories of human ancestors. PMID:26673156

  4. Sex differences in impulsive and compulsive behaviors: a focus on drug addiction.

    Science.gov (United States)

    Fattore, Liana; Melis, Miriam

    2016-09-01

    Sex differences in inhibition and self-regulation at a behavioral level have been widely described. From an evolutionary point of view, the different selection pressures placed on male and female hominids led them to differ in their behavioral strategies that allowed our species to survive during natural selection processes. These differences reflect changes in neural and structural plasticity that might be the core of sex differences, and of the susceptibility towards one psychiatric condition rather than another. The goal of the present review is to summarize current evidence for such a dichotomy in impulsive and compulsive behavior with a focus on drug addiction. Sex-dependent differences in drug abuse and dependence will be examined in the context of pathophysiological regulation of impulse and motivation by neuromodulators (i.e. gonadal hormones) and neurotransmitters (i.e. dopamine). Advances in the understanding of the sex differences in the capability to control impulses and motivational states is key for the determination of efficacious biologically based intervention and prevention strategies for several neuropsychiatric disorders where loss of impulse control and compulsivity are the core symptoms. © 2016 Society for the Study of Addiction.

  5. Early human occupation of Western Europe: Paleomagnetic dates for two paleolithic sites in Spain

    Science.gov (United States)

    Oms, O.; Parés, J. M.; Martínez-Navarro, B.; Agustí, J.; Toro, I.; Martínez-Fernández, G.; Turq, A.

    2000-01-01

    The lacustrine deposits infilling the intramontane Guadix-Baza Basin, in the Betic Range of Southern Spain, have yielded abundant well-preserved lithic artifacts. In addition, the lake beds contain a wide range of micromammals including Mimomys savini and Allophaiomys burgondiae and large mammals such as Mammuthus and Hippopotamus together with the African saber-toothed felid Megantereon. The association of the lithic artifacts along with the fossil assemblages, themselves of prime significance in the Eurasian mammal biochronology, is providing new insight into the controversy of the human settlement in Southern Europe. Despite the importance of the artifacts and fossil assemblage, estimates of the geological age of the site are still in conflict. Some attempts at dating the sediments have included biochronology, uranium series, amino acid racemization, and stratigraphic correlation with other well-dated sections in the basin, but so far have failed to yield unambiguous ages. Here we present paleomagnetic age dating at the relevant localities and thus provide useful age constraints for this critical paleoanthropological and mammal site. Our data provide firm evidence for human occupation in Southern Europe in the Lower Pleistocene, around 1 mega-annum ago. The current view of when and how hominids first dispersed into Europe needs to be reevaluated. PMID:10973485

  6. Gorilla MHC class I gene and sequence variation in a comparative context.

    Science.gov (United States)

    Hans, Jörg B; Bergl, Richard A; Vigilant, Linda

    2017-05-01

    Comparisons of MHC gene content and diversity among closely related species can provide insights into the evolutionary mechanisms shaping immune system variation. After chimpanzees and bonobos, gorillas are humans' closest living relatives; but in contrast, relatively little is known about the structure and variation of gorilla MHC class I genes (Gogo). Here, we combined long-range amplifications and long-read sequencing technology to analyze full-length MHC class I genes in 35 gorillas. We obtained 50 full-length genomic sequences corresponding to 15 Gogo-A alleles, 4 Gogo-Oko alleles, 21 Gogo-B alleles, and 10 Gogo-C alleles including 19 novel coding region sequences. We identified two previously undetected MHC class I genes related to Gogo-A and Gogo-B, respectively, thereby illustrating the potential of this approach for efficient and highly accurate MHC genotyping. Consistent with their phylogenetic position within the hominid family, individual gorilla MHC haplotypes share characteristics with humans and chimpanzees as well as orangutans suggesting a complex history of the MHC class I genes in humans and the great apes. However, the overall MHC class I diversity appears to be low further supporting the hypothesis that gorillas might have experienced a reduction of their MHC repertoire.

  7. Brain disorders and the biological role of music.

    Science.gov (United States)

    Clark, Camilla N; Downey, Laura E; Warren, Jason D

    2015-03-01

    Despite its evident universality and high social value, the ultimate biological role of music and its connection to brain disorders remain poorly understood. Recent findings from basic neuroscience have shed fresh light on these old problems. New insights provided by clinical neuroscience concerning the effects of brain disorders promise to be particularly valuable in uncovering the underlying cognitive and neural architecture of music and for assessing candidate accounts of the biological role of music. Here we advance a new model of the biological role of music in human evolution and the link to brain disorders, drawing on diverse lines of evidence derived from comparative ethology, cognitive neuropsychology and neuroimaging studies in the normal and the disordered brain. We propose that music evolved from the call signals of our hominid ancestors as a means mentally to rehearse and predict potentially costly, affectively laden social routines in surrogate, coded, low-cost form: essentially, a mechanism for transforming emotional mental states efficiently and adaptively into social signals. This biological role of music has its legacy today in the disordered processing of music and mental states that characterizes certain developmental and acquired clinical syndromes of brain network disintegration. © The Author (2014). Published by Oxford University Press.

  8. Why Barbie is perceived as beautiful.

    Science.gov (United States)

    Magro, A M

    1997-08-01

    The long-term acceptance and success of the Barbie doll suggests the physical characteristics of the doll are perceived as attractive. When viewed in the context of universal attractiveness, response to the doll raises the question why Barbie is perceived as attractive. Published paleontological data on hominid fossils indicate how the shapes and anatomical proportions of humans have evolved. Included in the fossils are phenotypic traits no longer prevalent in humans (primitive) and phenotypic traits that have become increasingly prevalent (derived). It is noted that the anatomical proportions of the Barbie doll are exaggerated and emphasize derived characteristics. It was proposed that in the perception of human form, derived traits are perceived as attractive while primitive traits are perceived as unattractive. Drawings and photographs were utilized to survey reactions to a comparison of primitive vs derived traits by 495 subjects, instructed to select the shape or proportion they considered more attractive. There was significant agreement among the subjects that derived anatomical traits were perceived as more attractive than primitive ones. The Barbie doll is illustrative of how human beauty has evolved and indicates elements of human form that appear beautiful. The doll emphasizes our derived evolutionary traits and, possibly, that is why the doll is perceived as attractive.

  9. Voyages Through Time: Everything Evolves

    Science.gov (United States)

    Fisher, Jane; Tarter, Jill; Devore, Edna; Pendleton, Yvonne; O'Sullivan, Kathleen; Burke, Meg

    2004-06-01

    The SETI Institute, the California Academy of Sciences, NASA Ames Research Center, and San Francisco State University have developed standards-based curriculum materials for a one-year high school integrated science course centered on the unifying theme of evolution. Scientists, teachers, curriculum writers, and media specialists are currently finalizing six modules that integrate astronomical, geological, and biological sciences as well as the history of science and technology. The sequence of lessons in each module is designed to promote students' understanding and skills as defined by the National Science Education Standards and Benchmarks for Science Literacy. The modules cover: Cosmic Evolution, Planetary Evolution, Origin of Life, Evolution of Life, Hominid Evolution, and the Evolution of Technology. The core lessons for all six modules are provided via CD-ROM, including instructional guidelines, science background information, and additional resources (print, audiovisual, software, WWW sites, and databases). These products will be published as a complete set for use as a yearlong science course and will also be available as individual modules for use in discipline-based courses. Evolutionary change is a powerful framework for studying our world and our place therein. It is a story of epic size, capable of inspiring awe and of expanding our sense of time and place. This story is the basis of Voyages Through Time.

  10. Direct radiocarbon dates for prehistoric paintings at the Altamira, El Castillo and Niaux caves

    International Nuclear Information System (INIS)

    Valladas, H.; Cachier, H.; Maurice, P.; Arnold, M.; Quiros, F.B. de; Valdes, V.C.; Uzquiano, P.

    1992-01-01

    Among things that most strikingly distinguish modern humans from other hominids and the rest of the animal kingdom is the ability to represent things and events pictorially. Complex paintings of the type discovered in the Altamira, El Castillo, Niaux and Lascaux caves represent an important stepping stone in the cultural evolution of humankind. Until now dates were derived from style or dated remains left by prehistoric visitors and could be biased by prolonged occupation or visits unrelated to painting activity. Here we report the first radiocarbon dates for the charcoal used to draw stylistically similar bisons in these caves: 14,000 ± 400 yr BP in the Spanish caves of Altamira, 12,990 ± 200 yr BP in El Castillo, and 12,890 ± 160 yr BP for a bison of different style in the French Pyrenean cave of Niaux. Our results demonstrate the imprecise nature of stylistic dating and show that painting dates derived from remains of human activities should be used with caution. (Author)

  11. An Early Pleistocene high-resolution paleoclimate reconstruction from the West Turkana (Kenya) HSPDP drill site

    Science.gov (United States)

    Stockhecke, Mona; Beck, Catherine; Brown, Erik T.; Cohen, Andrew; Deocampo, Daniel M.; Feibel, Craig S.; Pelletier, Jon D.; Rabideaux, Nathane M.; Sier, Mark

    2016-04-01

    The Hominin Sites and Paleolakes Drilling Project (HSPDP), and the related Olorgesailie Drilling Project (ODP), recovered ~2 km of drill core since 2012. At the HSPDP West Turkana Kaitio (WTK) site a 216 m-long core that covers the Early Pleistocene time window (1.3 to 1.87 Ma) during which hominids first expanded out of Africa and marine records document reorganization of tropical climate and the development of the strong Walker circulation. WTK carries particular interest for paleoclimate and paleoenvironmental reconstructions as it is located only 2.5 km from the location of one of the most complete hominin skeletons ever recovered (Nariokotome Boy). XRF core scanning data provide a means of evaluating records of past environmental conditions continuously and at high resolution. However, the record contains complex lithologies reflecting repeated episodes of inundation and desiccation along a dynamic lake margin. Here we present a methodological approach to address the highly variable lithostratigraphy of the East African records to establish comprehensive paleoclimate timeseries. The power spectrum of the presented hydroclimate record peaks at Milankovitch cycles, qualifying HSPDP drill cores from the Turkana Basin to be used as high-resolution Early Pleistocene paleoclimate archive. Comparing these data with marine climate reconstructions sheds light into athmospheric processes and continental climate dynamics.

  12. Culture, Urbanism and Changing Human Biology.

    Science.gov (United States)

    Schell, L M

    2014-04-03

    Anthropologists have long known that human activity driven by culture changes the environment. This is apparent in the archaeological record and through the study of the modern environment. Perhaps the largest change since the paleolithic era is the organization of human populations in cities. New environments can reshape human biology through evolution as shown by the evolution of the hominid lineage. Evolution is not the only process capable of reshaping our biology. Some changes in our human biology are adaptive and evolutionary while others are pathological. What changes in human biology may be wrought by the modern urban environment? One significant new change in the environment is the introduction of pollutants largely through urbanization. Pollutants can affect human biology in myriad ways. Evidence shows that human growth, reproduction, and cognitive functioning can be altered by some pollutants, and altered in different ways depending on the pollutant. Thus, pollutants have significance for human biologists and anthropologists generally. Further, they illustrate the bio-cultural interaction characterizing human change. Humans adapt by changing the environment, a cultural process, and then change biologically to adjust to that new environment. This ongoing, interactive process is a fundamental characteristic of human change over the millennia.

  13. Scientific controversies on biological knowledge construction: investigating a continued formation course for teachers with respect for human biological evolution

    Directory of Open Access Journals (Sweden)

    Marcelo Erdmann Bulla

    2016-08-01

    Full Text Available The research here presented has as central theme the human biological evolution, its scientific controversies and the continued formation of science and biology teachers. We evaluate the development of a teaching sequence on the topic, emphasizing the scientific controversy regarding the supposed fossil hominid Ardipithecus ramidus (“Ardi” in a continued formation course for teachers of science and biology of basic public network Cascavel-PR and region. The empirical work involved collecting data from the responses provided by teachers to an initial questionnaire and a final. The analysis and data discussion has highlighted the importance of scientific controversy for the development of scientific knowledge and the urgency to insert the contents of human evolution in subjects on the initial formation of courses in licentiate of Biological Sciences. It is necessary also to offer continued formation courses to include such content for teachers already inserted in schools. We conclude that teaching biology and science using scientific controversies may be in satisfactory teaching tool to introduce the history and nature of science, since scientific activity is permeated by conflicts.

  14. Evolutionary history of enigmatic bears in the Tibetan Plateau-Himalaya region and the identity of the yeti.

    Science.gov (United States)

    Lan, Tianying; Gill, Stephanie; Bellemain, Eva; Bischof, Richard; Nawaz, Muhammad Ali; Lindqvist, Charlotte

    2017-12-13

    Although anecdotally associated with local bears ( Ursus arctos and U. thibetanus ), the exact identity of 'hominid'-like creatures important to folklore and mythology in the Tibetan Plateau-Himalaya region is still surrounded by mystery. Recently, two purported yeti samples from the Himalayas showed genetic affinity with an ancient polar bear, suggesting they may be from previously unrecognized, possibly hybrid, bear species, but this preliminary finding has been under question. We conducted a comprehensive genetic survey of field-collected and museum specimens to explore their identity and ultimately infer the evolutionary history of bears in the region. Phylogenetic analyses of mitochondrial DNA sequences determined clade affinities of the purported yeti samples in this study, strongly supporting the biological basis of the yeti legend to be local, extant bears. Complete mitochondrial genomes were assembled for Himalayan brown bear ( U. a. isabellinus ) and black bear ( U. t. laniger ) for the first time. Our results demonstrate that the Himalayan brown bear is one of the first-branching clades within the brown bear lineage, while Tibetan brown bears diverged much later. The estimated times of divergence of the Tibetan Plateau and Himalayan bear lineages overlap with Middle to Late Pleistocene glaciation events, suggesting that extant bears in the region are likely descendants of populations that survived in local refugia during the Pleistocene glaciations. © 2017 The Authors.

  15. The Paradox of Isochrony in the Evolution of Human Rhythm

    Directory of Open Access Journals (Sweden)

    Andrea Ravignani

    2017-11-01

    Full Text Available Isochrony is crucial to the rhythm of human music. Some neural, behavioral and anatomical traits underlying rhythm perception and production are shared with a broad range of species. These may either have a common evolutionary origin, or have evolved into similar traits under different evolutionary pressures. Other traits underlying rhythm are rare across species, only found in humans and few other animals. Isochrony, or stable periodicity, is common to most human music, but isochronous behaviors are also found in many species. It appears paradoxical that humans are particularly good at producing and perceiving isochronous patterns, although this ability does not conceivably confer any evolutionary advantage to modern humans. This article will attempt to solve this conundrum. To this end, we define the concept of isochrony from the present functional perspective of physiology, cognitive neuroscience, signal processing, and interactive behavior, and review available evidence on isochrony in the signals of humans and other animals. We then attempt to resolve the paradox of isochrony by expanding an evolutionary hypothesis about the function that isochronous behavior may have had in early hominids. Finally, we propose avenues for empirical research to examine this hypothesis and to understand the evolutionary origin of isochrony in general.

  16. Cosmic evolution, life and man

    International Nuclear Information System (INIS)

    Oro, J.

    1995-01-01

    Among the most basic problems confronting science are those regarding the origin of the universe, the origin of life and the origin of man. This general overview starts (1) with a brief introduction addressed primarily to the Cyril Ponnamperuma Memorial. Then, the thesis is presented that the appearance of life and intelligence on our planet can be understood as the result of a number of cosmic and biological evolutionary processes, including (2) the stellar thermonuclear synthesis of the biogenic elements other than hydrogen (C, N, O, P and S), their dispersal into space, and their combination into circumstellar and interstellar molecules. (3) The formation of the Solar System and the Earth-Moon System. (4) The role of comets and carbonaceous chondrites in contributing organic matter to the primitive Earth. (5) The prebiotics synthesis of amino acids, purines, pyrimidines, fatty acids, and other biochemical monomers. (6) The prebiotic condensation reactions leading to the synthesis of oligomers such as oligonucleotides and oligopeptides, with replicative and catalytic activities. (7) The synthesis of amphiphilic lipids, and their self-assembly into liposomes with bi-layered membranes. (8) The formation of protocellular structures. (9) The activation of protocells into a functioning Darwin's ancestral cell. (10) Early evolution of life. (11) The K-T boundary event and the disappearance of dinosaurs. (12) Evolution of hominids leading to Homo sapiens. (13) The rapid development of civilization. (14) The exploration of the Solar System. (15) Life beyond our planetary system. (16) Epilogue. Peace from cosmic evolution? (Abstract only)

  17. Visitors views of human origins after visiting the Cradle of Humankind World Heritage Site

    Directory of Open Access Journals (Sweden)

    Anthony Lelliott

    2016-02-01

    Full Text Available The Cradle of Humankind World Heritage Site, west of Johannesburg, was designated in 1999 because of its importance as a locality where numerous hominid fossils have been discovered since the 1930s. In this article, responses to questions from a survey of more than 800 adult visitors to the Cradle of Humankind visitor centres are analysed, covering their understanding of the concept of the "cradle" and their views on human evolution. Findings indicated that 63% of the respondents conceptualised the cradle as the origin or birthplace of humankind, and a similar proportion thought that nowhere else could be called the Cradle of Humankind (77% of people of South African nationality thought this. Nearly 60% of respondents accepted that humans evolved from an ape-like ancestor, while 25% disagreed. South Africans were less likely to accept human evolution than their international counterparts. The great majority of participants who accepted human evolution based their agreement on various forms of evidence and their knowledge of evolution. A religious foundation was used for their rationale by 60% of those who rejected evolution, with 33% citing evidence for their rejection. The implications of the findings are discussed in the light of public awareness and human origins.

  18. Out of Africa: modern human origins special feature: human origins: out of Africa.

    Science.gov (United States)

    Tattersall, Ian

    2009-09-22

    Our species, Homo sapiens, is highly autapomorphic (uniquely derived) among hominids in the structure of its skull and postcranial skeleton. It is also sharply distinguished from other organisms by its unique symbolic mode of cognition. The fossil and archaeological records combine to show fairly clearly that our physical and cognitive attributes both first appeared in Africa, but at different times. Essentially modern bony conformation was established in that continent by the 200-150 Ka range (a dating in good agreement with dates for the origin of H. sapiens derived from modern molecular diversity). The event concerned was apparently short-term because it is essentially unanticipated in the fossil record. In contrast, the first convincing stirrings of symbolic behavior are not currently detectable until (possibly well) after 100 Ka. The radical reorganization of gene expression that underwrote the distinctive physical appearance of H. sapiens was probably also responsible for the neural substrate that permits symbolic cognition. This exaptively acquired potential lay unexploited until it was "discovered" via a cultural stimulus, plausibly the invention of language. Modern humans appear to have definitively exited Africa to populate the rest of the globe only after both their physical and cognitive peculiarities had been acquired within that continent.

  19. Ancient origin and gene mosaicism of the progenitor of Mycobacterium tuberculosis.

    Directory of Open Access Journals (Sweden)

    M Cristina Gutierrez

    2005-09-01

    Full Text Available The highly successful human pathogen Mycobacterium tuberculosis has an extremely low level of genetic variation, which suggests that the entire population resulted from clonal expansion following an evolutionary bottleneck around 35,000 y ago. Here, we show that this population constitutes just the visible tip of a much broader progenitor species, whose extant representatives are human isolates of tubercle bacilli from East Africa. In these isolates, we detected incongruence among gene phylogenies as well as mosaic gene sequences, whose individual elements are retrieved in classical M. tuberculosis. Therefore, despite its apparent homogeneity, the M. tuberculosis genome appears to be a composite assembly resulting from horizontal gene transfer events predating clonal expansion. The amount of synonymous nucleotide variation in housekeeping genes suggests that tubercle bacilli were contemporaneous with early hominids in East Africa, and have thus been coevolving with their human host much longer than previously thought. These results open novel perspectives for unraveling the molecular bases of M. tuberculosis evolutionary success.

  20. Lecture One: Rediscovering Darwin for theology – Rethinking human personhood

    Directory of Open Access Journals (Sweden)

    J. Wentzel van Huyssteen

    2017-11-01

    Full Text Available In a series of three articles, presented at the Goshen Annual Conference on Science and Religion in 2015, with the theme ‘Interdisciplinary Theology and the Archeology of Personhood’, J. Wentzel van Huyssteen considers the problem of human evolution – also referred to as ‘the archaeology of personhood’ – and its broader impact on theological anthropology. These Goshen Lectures explore the potentiality that the history of human evolution provides bridge theories to theological anthropology and thus to a positive and constructive way of appropriating Darwinian thought for a public, interdisciplinary Christian theology. Lecture One tracks a select number of contemporary proposals for the evolution of aspects of human personhood. These aspects were of significance for Darwin: the evolution of cognition; the evolution of imagination, music and language; the evolution of morality; and the evolution of the religious disposition. The article acknowledges the close ties to hominid ancestors and focuses on the emergence of human distinctiveness, consciousness and personhood, and the propensity for religious awareness and experience.

  1. Right-handed fossil humans.

    Science.gov (United States)

    Lozano, Marina; Estalrrich, Almudena; Bondioli, Luca; Fiore, Ivana; Bermúdez de Castro, José-Maria; Arsuaga, Juan Luis; Carbonell, Eudald; Rosas, Antonio; Frayer, David W

    2017-11-01

    Fossil hominids often processed material held between their upper and lower teeth. Pulling with one hand and cutting with the other, they occasionally left impact cut marks on the lip (labial) surface of their incisors and canines. From these actions, it possible to determine the dominant hand used. The frequency of these oblique striations in an array of fossil hominins documents the typically modern pattern of 9 right- to 1 left-hander. This ratio among living Homo sapiens differs from that among chimpanzees and bonobos and more distant primate relatives. Together, all studies of living people affirm that dominant right-handedness is a uniquely modern human trait. The same pattern extends deep into our past. Thus far, the majority of inferred right-handed fossils come from Europe, but a single maxilla from a Homo habilis, OH-65, shows a predominance of right oblique scratches, thus extending right-handedness into the early Pleistocene of Africa. Other studies show right-handedness in more recent African, Chinese, and Levantine fossils, but the sample compiled for non-European fossil specimens remains small. Fossil specimens from Sima del los Huesos and a variety of European Neandertal sites are predominately right-handed. We argue the 9:1 handedness ratio in Neandertals and the earlier inhabitants of Europe constitutes evidence for a modern pattern of handedness well before the appearance of modern Homo sapiens. © 2017 Wiley Periodicals, Inc.

  2. Stamping, Clapping and Chanting: An Ancient Learning Pathway?

    Directory of Open Access Journals (Sweden)

    Marion M. Long

    2006-04-01

    Full Text Available In this review I explore the effect of temporal integration as a means of improving learning in schoolchildren. I focus first on theorists that have linked physical activity with a positive effect on children’s learning and second to psychological studies that have established the existence of innate temporal patterns. These findings are related to a model of temporal integration that I have developed from Croce’s writings on aesthetics (1900. From philosophy to neurology, I discuss recent neurological findings relating to timing and conclude that an organ of temporal integration, regulation and coordination operates in the brain with respect to physical, intuitive and higher cognitive function. I link recent findings in neurophysiology to notably similar findings in recent biomusicological studies. The finding that humans have an involuntary physical response to loud, low-frequency sounds are attributed to an innate legacy of proto-music and proto-dance behaviour among hominids. I develop the model of temporal integration further by examining the literature on stamping and clapping patterns of ancient traditional dances in relation to Husserl’s writings on theoretical succession. From philosophy to pedagogy, I summarise the review by proposing stamping, clapping and chanting as a means of achieving improved temporal integration.

  3. Preliminary results of combined ESR/U-series dating of fossil teeth from Longgupo cave, China

    International Nuclear Information System (INIS)

    Han, Fei; Bahain, Jean-Jacques; Falgueres, Christophe; Shao, Qingfeng; Boeda, Eric; Hou, Yamei; Huang, Wanbo; Rasse, Michel; Wei, Guangbiao; Garcia, Tristan; Yin, Gongming

    2012-01-01

    Longgupo Cave site, located in Wushan County, Chongqing, China has attracted continuous attention since its discovery of hominid remains in association with late Pliocene-early Pleistocene fauna and numerous lithic artefacts. In 2003-2006, new excavation was carried out on this site, allowing the description of a detailed stratigraphy of the highly complex cave in-fillings and the sampling of teeth for combined ESR/U-series analyses. Here we report preliminary dating results of seven herbivorous fossil teeth from different archaeological layers of the lowest geological unit (C III). Uranium-series analyses indicate that no obvious uranium leaching has occurred and all the teeth (except one) underwent a very recent uranium uptake history. The obtained US-ESR results show that the age of six teeth are basically consistent, between similar to 1.4 and 1.8 Ma. At the same time, we observed an inverse correlation of two samples with the stratigraphic sequence. This could be caused by the distinct uranium uptake history of one sample, high uranium content in the enamel for another or bad estimation of external dose rate. Due to the complexity of the stratigraphic sequence, supplementary in situ gamma dose rate measurement should be performed for all the samples during the following excavations in order to confirm this preliminary ESR/U-series chronology. (authors)

  4. Neuromusculoskeletal computer modeling and simulation of upright, straight-legged, bipedal locomotion of Australopithecus afarensis (A.L. 288-1).

    Science.gov (United States)

    Nagano, Akinori; Umberger, Brian R; Marzke, Mary W; Gerritsen, Karin G M

    2005-01-01

    The skeleton of Australopithecus afarensis (A.L. 288-1, better known as "Lucy") is by far the most complete record of locomotor morphology of early hominids currently available. Even though researchers agree that the postcranial skeleton of Lucy shows morphological features indicative of bipedality, only a few studies have investigated Lucy's bipedal locomotion itself. Lucy's energy expenditure during locomotion has been the topic of much speculation, but has not been investigated, except for several estimates derived from experimental data collected on other animals. To gain further insights into how Lucy may have walked, we generated a full three-dimensional (3D) reconstruction and forward-dynamic simulation of upright bipedal locomotion of this ancient human ancestor. Laser-scanned 3D bone geometries were combined with state-of-the-art neuromusculoskeletal modeling and simulation techniques from computational biomechanics. A detailed full 3D neuromusculoskeletal model was developed that encompassed all major bones, joints (10), and muscles (52) of the lower extremity. A model of muscle force and heat production was used to actuate the musculoskeletal system, and to estimate total energy expenditure during locomotion. Neural activation profiles for each of the 52 muscles that produced a single step of locomotion, while at the same time minimizing the energy consumed per meter traveled, were searched through numerical optimization. The numerical optimization resulted in smooth locomotor kinematics, and the predicted energy expenditure was appropriate for upright bipedal walking in an individual of Lucy's body size. (c) 2004 Wiley-Liss, Inc.

  5. Milk composition of captive vervet monkey (Chlorocebus pygerythrus) and rhesus macaque (Macaca mulatta) with observations on gorilla (Gorilla gorilla gorilla) and white handed gibbon (Hylobates lar).

    Science.gov (United States)

    Osthoff, G; Hugo, A; de Wit, M; Nguyen, T P M; Seier, J

    2009-04-01

    The nutrient content and fatty acid composition of vervet monkey milk has been determined and is compared with rhesus macaque, and two hominoid apes, the white handed gibbon and gorilla. With 15.7+/-4.1 g protein, 33.1+/-9.4 g fat, and 85.1+/-7.5 g lactose per kg milk, vervet monkey milk does not differ from that of rhesus macaque, and is within the range of other primates. Small amounts (>1 g kg(-1)) of oligosaccharides, glucose, galactose and fucose were noted. In comparison, gorilla milk has a low fat content of 13.8 g kg(-1), but contains high levels of oligosaccharides at 7.0 g kg(-1) milk. The hominoid partner, the white handed gibbon, contains no oligosaccharides and a milk fat content similar to other hominoid species. Differences between vervet monkey and rhesus macaque milks were observed in the electrophoretic pattern of the milk proteins, mainly amongst the kappa- and gamma-caseins, which also differ from that of the hominids. The fatty acid contents of these milks differ from studies where a natural diet of leafy material was available in that a low content of alpha-linolenic acid (18:3n-3) was noted. A phylogenetic effect is observed for the content of 8:0, 10:0 fatty acids between the Cercopithecidae and Hominoidea, and a further phylogenetic effect suggested between the Hylobatidae and Hominidae.

  6. Possible brucellosis in an early hominin skeleton from sterkfontein, South Africa.

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    Ruggero D'Anastasio

    Full Text Available We report on the paleopathological analysis of the partial skeleton of the late Pliocene hominin species Australopithecus africanus Stw 431 from Sterkfontein, South Africa. A previous study noted the presence of lesions on vertebral bodies diagnosed as spondylosis deformans due to trauma. Instead, we suggest that these lesions are pathological changes due to the initial phases of an infectious disease, brucellosis. The macroscopic, microscopic and radiological appearance of the lytic lesions of the lumbar vertebrae is consistent with brucellosis. The hypothesis of brucellosis (most often associated with the consumption of animal proteins in a 2.4 to 2.8 million year old hominid has a host of important implications for human evolution. The consumption of meat has been regarded an important factor in supporting, directing or altering human evolution. Perhaps the earliest (up to 2.5 million years ago paleontological evidence for meat eating consists of cut marks on animal remains and stone tools that could have made these marks. Now with the hypothesis of brucellosis in A. africanus, we may have evidence of occasional meat eating directly linked to a fossil hominin.

  7. The fossil record as a tool in cyclo stratigraphy: the incidence of Milankovitch-scale palaeoenvironmental changes on palaeocommunities

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Tovar, F. J.

    2013-06-01

    Cyclo stratigraphic analysis at the Milankovitch scale has to date mainly been approached through the sedimentary record, although palaeontological data (the fossil record) is known to provide useful evidence of orbital-scale cycles of precession, obliquity and eccentricity. Orbit ally induced marine and terrestrial palaeoenvironmental changes determine variable responses on the part of the resident communities. Aside from the disruption of communities, complex evolutionary responses including stasis, speciation and extinction phenomena may take place. Cyclic variations in the marine past-biota at the community level, or in some particular taxa, have often been associated with orbit ally induced changes in palaeoenvironmental parameters. Cyclo stratigraphic research into foraminifera, radiol aria and nanno fossil data, mainly from Cretaceous sediments, may contribute significantly to our understanding of the planktonic community's response, whereas the response of the benthic community, deriving mainly from benthic foraminifera and trace fossils, has been studied to a lesser extent. Recognition of Milankovitch cycles from terrestrial palaeocommunities is relatively scarce and based mainly on the study of Pliocene-Miocene pollen assemblages. Astronomical forced climate changes determine well known variations in the distribution of terrestrial vegetation, but can also affect the terrestrial animal community, including hominid populations (migration, dispersion and colonisation). (Author)

  8. Two SE Spanish middle palaeolithic sites with Neanderthal remains: Sima de las Palomas del Cabezo Gordo and Cueva Negra del Estrecho del Río Quípar (Murcia province

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    M. J. Walker, F.S.A.

    1998-12-01

    Full Text Available This article presents preliminary findings from excavations at two recently-discovered cave sites in Murcia (SE. Spain with Neanderthal hominid skeletal remains, middle palaeolithic tools, and early Upper Pleistocene faunal remains. The sites are in contrasting environments, the shaft of Sima de las Palomas being near the coast whereas the Cueva Negra rock-shelter is in the hinterland. The origins and development of the field research project are outlined with special reference to strategical and methodological considerations. Cueva Negra has afforded half-a-dozen adult Neanderthal teeth and the shaft of a forearm bone. Sima de las Palomas suffered damage from nineteenth-century mining that exposed an 18-metre-high column of breccia in a natural shaft, and geophysical determinations suggest that it spans a period from roughly 125,000 to 50,000 BP. Adult and juvenile Neanderthal teeth and bones have been excavated at the top of the column and many others have been found sifting mine rubble both outside the cavern and on the floor inside, some of which have characteristics that are more in keeping with pre-Neanderthal morphology.

  9. Gender, risk assessment, and political ambition.

    Science.gov (United States)

    Sweet-Cushman, Jennie

    2016-01-01

    In the United States, women have long held the right to vote and can participate fully in the political process, and yet they are underrepresented at all levels of elected office. Worldwide, men's dominance in the realm of politics has also been the norm. To date, scholars have focused on supply-side and demand-side explanations of women's underrepresentation but differences in how men and women assess electoral risk (the risk involved in seeking political office) are not fully explained. To fill this gap, I explore how evolutionary theory offers insights into gendered differences in political ambition and the evaluation of electoral risk. Using the framework of life-history theory, I hypothesize that both cognitive and environmental factors in human evolution, particularly as they relate to sexual selection and social roles, have shaped the psychology of ambition in gendered ways affecting contemporary politics. Cognitive risk-assessment mechanisms evolving in the hominid line came to be expressed differently in females and males, in women and men. These gendered expressions plausibly reflect differentiable environmental pressures in the past and may help explain behaviors in and barriers to women's electoral political activity in the present. If so, then the success of efforts to increase such activity - or, regressively, to suppress it - may be better understood.

  10. Naledi: An example of how natural phenomena can inspire metaphysical assumptions

    Directory of Open Access Journals (Sweden)

    Francois Durand

    2017-09-01

    Full Text Available A new fossil site was discovered in the Rising Star Cave in 2013 in the Cradle of Humankind in South Africa. This site which has yielded 1550 hominin bones so far is considered to be one of the richest palaeoanthropological sites in the world. The deposition of the fossils in a remote part of the cave system, approximately 100 m from the entrance, has resulted in a great deal of speculation. The relative inaccessibility of the site and the number of fossil bones it contained and the fact that virtually all these bones were those of a single species of hominid led to the conclusion that the bones were not deposited because of natural sedimentary processes, but that these phenomena were evidence of purposeful disposal or even burial of the dead by hominins. If this assumption is true, it would be the earliest evidence of a metaphysical awareness in humankind. The tenuous evidence on which this hypothesis rests will be discussed and a more plausible alternative explanation where water and gravity were responsible for the deposition of the remains is forwarded.

  11. Emergence of a Homo sapiens-specific gene family and chromosome 16p11.2 CNV susceptibility.

    Science.gov (United States)

    Nuttle, Xander; Giannuzzi, Giuliana; Duyzend, Michael H; Schraiber, Joshua G; Narvaiza, Iñigo; Sudmant, Peter H; Penn, Osnat; Chiatante, Giorgia; Malig, Maika; Huddleston, John; Benner, Chris; Camponeschi, Francesca; Ciofi-Baffoni, Simone; Stessman, Holly A F; Marchetto, Maria C N; Denman, Laura; Harshman, Lana; Baker, Carl; Raja, Archana; Penewit, Kelsi; Janke, Nicolette; Tang, W Joyce; Ventura, Mario; Banci, Lucia; Antonacci, Francesca; Akey, Joshua M; Amemiya, Chris T; Gage, Fred H; Reymond, Alexandre; Eichler, Evan E

    2016-08-11

    Genetic differences that specify unique aspects of human evolution have typically been identified by comparative analyses between the genomes of humans and closely related primates, including more recently the genomes of archaic hominins. Not all regions of the genome, however, are equally amenable to such study. Recurrent copy number variation (CNV) at chromosome 16p11.2 accounts for approximately 1% of cases of autism and is mediated by a complex set of segmental duplications, many of which arose recently during human evolution. Here we reconstruct the evolutionary history of the locus and identify bolA family member 2 (BOLA2) as a gene duplicated exclusively in Homo sapiens. We estimate that a 95-kilobase-pair segment containing BOLA2 duplicated across the critical region approximately 282 thousand years ago (ka), one of the latest among a series of genomic changes that dramatically restructured the locus during hominid evolution. All humans examined carried one or more copies of the duplication, which nearly fixed early in the human lineage--a pattern unlikely to have arisen so rapidly in the absence of selection (P sapiens-specific duplication. In summary, the duplicative transposition of BOLA2 at the root of the H. sapiens lineage about 282 ka simultaneously increased copy number of a gene associated with iron homeostasis and predisposed our species to recurrent rearrangements associated with disease.

  12. Radius of Paranthropus robustus from member 1, Swartkrans formation, South Africa.

    Science.gov (United States)

    Grine, F E; Susman, R L

    1991-03-01

    Recently recovered hominid postcrania from Member 1, Swartkrans Formation include the proximal and distal ends of a right radius attributed to a single individual of Paranthropus robustus. These fossils are essentially similar to Australopithecus afarensis, A. africanus, and P. boisei homologues. The head manifests an ape-like circumferentia articularis, and the distal end has prominent medial, dorsal, and lateral tubercles and a well developed brachioradialis crest, features also commonly exhibited by extant great apes. The volar set of the P. robustus radiocarpal joint, like that of Australopithecus homologues, more closely resembles the neutral condition exhibited by Homo than the greater flexion evinced by living apes. Compared with fossil and recent specimens of Homo, the configuration of the P. robustus radial head suggests enhanced stability against medial displacement during pronation and supination; the strong crest for the attachment of brachioradialis may attest to enhanced forearm flexor capability. In addition, this crest and the prominent dorsal tubercles may indicate enhanced hand extensor and, therefore, hand flexor capabilities. The differences in radial morphology between Paranthropus and Homo may relate to significant behavioral differences between these two synchronic taxa.

  13. The evolution of the meningeal vascular system in the human genus: From brain shape to thermoregulation.

    Science.gov (United States)

    Bruner, Emiliano; Mantini, Simone; Musso, Fabio; De La Cuétara, José Manuel; Ripani, Maurizio; Sherkat, Shahram

    2011-01-01

    The imprints of the middle meningeal vessels make it possible to analyze vascularization in fossil specimens. The association between changes in the cortical anatomy and vascular organization raises questions about the actual physiological meaning of these features, most of all when dealing with the origin of the modern human brain. Metabolism and thermoregulation may be relevant factors in influencing morphological adaptations between brain and vessels. This study is aimed at investigating the relationships between endocranial morphology and endocranial vessels in modern humans and to analyze the pattern of heat dissipation through the endocranial surface in fossil specimens. Through angiotomography, it is possible to make an anatomical reconstruction of the meningeal and cerebral vessels, providing information on the morphology of the endocranial vascular system. At the same time, digital modeling can be performed to investigate the relationships between the endocranial geometry and physical properties such as heat dissipation patterns in extinct hominids. The middle meningeal network is largely independent from the cerebral vascular system. Furthermore, in adults, the medium and upper tracts of the middle meningeal artery shows scarce or absent blood flow. Parietal bossing in modern humans involves relative cooling of the cortical surface at the supramarginal gyrus. The evidence does not support a thermoregulatory role for the meningeal vascular network, at least in adult normal blood flow conditions. On the other hand, biomechanical protective functions (hydraulic skeleton for shock adsorption) cannot be ruled out. © 2010 Wiley-Liss, Inc.

  14. USER principle as relating the human environmental management

    International Nuclear Information System (INIS)

    Kernakis

    2005-01-01

    The environmental variable can be understood as the resulting biosphere space that has suffered the occurrence of pre-biotic, biotic and anthropic processes. This necessary expansion of the environmental frontier allows understand clearly the magnitude the great complexity of the process immersed in the current environmental problematic. This, taking into account the analysis of the reference systems used by the different species to face their interaction with the nature. Hence, it is necessary to evaluate the human referential process of reality, as a responsible specie of the derange shown by the Environmental Mother Eve. The latest hominid development of an Artificial Reference System (ARS) (linguistic symbols), points to the constitution of the casual factor that triggers such an environmental problematic. The expansive dynamics accomplished by the ARS has not always made reference to the natural ambience that created them. The formulation of the Unprivilegeness of Symbolic Endogenous Referents (USER) Principle (Kernakis 1986, 1997), as a necessary epistemological consequence of the Special Relativity from Einstein, entails to the reversion of the local privileges created by the ARS, stating a referential crisis as alternative to a potential environmental collapse. AII these could lead to the most intra-specific understanding with the nature, antonomastical fragmented by the privileges of the ARS. Such integration species-nature would allow to make possible an spontaneous natural-cultural arranging of the environmental balance

  15. Auditory capacities in Middle Pleistocene humans from the Sierra de Atapuerca in Spain.

    Science.gov (United States)

    Martínez, I; Rosa, M; Arsuaga, J-L; Jarabo, P; Quam, R; Lorenzo, C; Gracia, A; Carretero, J-M; Bermúdez de Castro, J-M; Carbonell, E

    2004-07-06

    Human hearing differs from that of chimpanzees and most other anthropoids in maintaining a relatively high sensitivity from 2 kHz up to 4 kHz, a region that contains relevant acoustic information in spoken language. Knowledge of the auditory capacities in human fossil ancestors could greatly enhance the understanding of when this human pattern emerged during the course of our evolutionary history. Here we use a comprehensive physical model to analyze the influence of skeletal structures on the acoustic filtering of the outer and middle ears in five fossil human specimens from the Middle Pleistocene site of the Sima de los Huesos in the Sierra de Atapuerca of Spain. Our results show that the skeletal anatomy in these hominids is compatible with a human-like pattern of sound power transmission through the outer and middle ear at frequencies up to 5 kHz, suggesting that they already had auditory capacities similar to those of living humans in this frequency range.

  16. The Sima de los Huesos (Burgos, northern Spain): palaeoenvironment and habitats of Homo heidelbergensis during the Middle Pleistocene

    Science.gov (United States)

    García, Nuria; Arsuaga, Juan Luis

    2011-06-01

    Interpreting how environmental dynamics respond to global climate change and how this has affected human evolution and dispersal is an on-going topic of debate. During the early Middle Pleistocene (˜0.6-0.4 Ma), as compared to earlier, environmental conditions were relatively more stable, with longer climatic cycles alternating between open and forested landscapes. During this interval, humans spread successfully providing an important number of fossil sites where fossils or tools are reported. The Atapuerca-Sima de los Huesos (Burgos, northern Spain) site (Atapuerca-SH) is one of the earliest localities with hominin evidence in the European Middle Pleistocene, with the most important accumulation of Homo heidelbergensis so far. We have analyzed the abundant faunal record from Sima de los Huesos, which is mainly comprised of carnivores, in order to approach an interpretation of the palaeoenvironmental circumstances where these hominids inhabited within the Sierra. Other sites from Sierra de Atapuerca referred to the same Faunal Unit (FU 6), are roughly contemporaneous, and include important ungulates, which are here analyzed with Atapuerca-SH. Additional information provided by isotopic analysis helps elucidate the ancient ecology of taxa present in Sima de los Huesos allowing for an accurate portrayal of the setting in which humans lived. The timing of the spread of Homo heidelbergensis is dominated by a relative climatic and environmental stability and points to a landscape dominated by savannah-like open woodland.

  17. Exploring the Potential of Laser Ablation Carbon Isotope Analysis for Examining Ecology during the Ontogeny of Middle Pleistocene Hominins from Sima de los Huesos (Northern Spain).

    Science.gov (United States)

    Garcia, Nuria; Feranec, Robert S; Passey, Benjamin H; Cerling, Thure E; Arsuaga, Juan Luis

    2015-01-01

    Laser ablation of tooth enamel was used to analyze stable carbon isotope compositions of teeth of hominins, red deer, and bears from middle Pleistocene sites in the Sierra de Atapuerca in northern Spain, to investigate the possibility that this technique could be used as an additional tool to identify periods of physiological change that are not detectable as changes in tooth morphology. Most of the specimens were found to have minimal intra-tooth variation in carbon isotopes (< 2.3‰), suggesting isotopically uniform diets through time and revealing no obvious periods of physiological change. However, one of the two sampled hominin teeth displayed a temporal carbon isotope shift (3.2‰) that was significantly greater than observed for co-occurring specimens. The δ13C value of this individual averaged about -16‰ early in life, and -13‰ later in life. This isotopic change occurred on the canine crown about 4.2 mm from the root, which corresponds to an approximate age of two to four years old in modern humans. Our dataset is perforce small owing to the precious nature of hominid teeth, but it demonstrates the potential utility of the intra-tooth isotope profile method for extracting ontogenetic histories of human ancestors.

  18. [Sierra of the Atapuerca, thinking about the evolution].

    Science.gov (United States)

    Carbonell, Eudald

    2007-01-01

    Homo sapiens walks to the future in a uncertain way. The fosil evidences from the lithosphere can help us to get into know the social and cultural evolution of all the species that have precede us and even our own. Atapuerca, with more than 1.2 MA old of fossilized history from the Pleistocene to the Holocene is throwing a scientific message through the study of all its archaeological sites. There are thousands of animal and human fossils in Trinchera del Ferrocarril, Cueva de Gran Dolina, Sima del Elefante and Galeria that yield information on the cultural cannibalism practices by Homo antecessor 900,000 years ago, and the hunting and gathering that Homo heidelbergensis developed 400,000 years ago. Finally in the Sima de los Huesos, with a similar chronology than at the H. heidelbergensis sites from the Trinchera del Ferrocarril, we find the first intentional accumulation of hominid bodies. These contributions are significant to the knowledge of the biological and cultural human evolution and permits to deepen it empirically. We hope that understanding the message we will be able to improve our species through the socialization of the scientific knowledge.

  19. A probabilistic approach to the assessment of some life history pattern parameters in a Middle Pleistocene human population.

    Science.gov (United States)

    Durand, A I; Ipina, S L; Bermúdez de Castro, J M

    2000-06-01

    Parameters of a Middle Pleistocene human population such as the expected length of the female reproductive period (E(Y)), the expected interbirth interval (E(X)), the survival rate (tau) for females after the expected reproductive period, the rate (phi(2)) of women who, given that they reach first birth, do not survive to the end of the expected reproductive period, and the female infant plus juvenile mortality rate (phi(1)) have been assessed from a probabilistic standpoint provided that such a population were stationary. The hominid sample studied, the Sima de los Huesos (SH) cave site, Sierra de Atapuerca (Spain), is the most exhaustive human fossil sample currently available. Results suggest that the Atapuerca (SH) sample can derive from a stationary population. Further, in the case that the expected reproductive period ends between 37 and 40 yr of age, then 24 less, similarE(Y) less, similar27 yr, E(X)=3 yr, 0.224

  20. The human gluteus maximus and its role in running.

    Science.gov (United States)

    Lieberman, Daniel E; Raichlen, David A; Pontzer, Herman; Bramble, Dennis M; Cutright-Smith, Elizabeth

    2006-06-01

    The human gluteus maximus is a distinctive muscle in terms of size, anatomy and function compared to apes and other non-human primates. Here we employ electromyographic and kinematic analyses of human subjects to test the hypothesis that the human gluteus maximus plays a more important role in running than walking. The results indicate that the gluteus maximus is mostly quiescent with low levels of activity during level and uphill walking, but increases substantially in activity and alters its timing with respect to speed during running. The major functions of the gluteus maximus during running are to control flexion of the trunk on the stance-side and to decelerate the swing leg; contractions of the stance-side gluteus maximus may also help to control flexion of the hip and to extend the thigh. Evidence for when the gluteus maximus became enlarged in human evolution is equivocal, but the muscle's minimal functional role during walking supports the hypothesis that enlargement of the gluteus maximus was likely important in the evolution of hominid running capabilities.

  1. The human retinoblastoma susceptibility gene (RB1): an evolutionary story in primates.

    Science.gov (United States)

    Viana, Maria C; Tavares, William C; Brant, Ayslan C; Boroni, Mariana; Seuánez, Héctor N

    2017-06-01

    The tumor suppressor gene RB1 (Human Retinoblastoma Susceptibility Gene) plays a prominent role in normal development, gene transcription, DNA replication, repair, and mitosis. Its complete biallelic dysfunction in retinoblasts is the main cause of retinoblastoma in the human. Although this gene has been evolutionary conserved, comparisons between the reference and human RB1 coding region with its counterparts in 19 non-human primates showed 359 sites where nucleotide replacements took place during the radiation of these species. These resulted in missense substitutions in 97 codons, 91 of which by amino acids with radically different physicochemical properties. Several in frame deletions and two insertions were also observed in the N-terminal region of the pRB protein where the highest number of amino acid substitutions and radical amino changes were found. Fifty-six codons were inferred to be under negative selection and five under positive selection. Differences in codon usage showed evident phylogenetic signals, with hominids generally presenting higher indices of codon bias than other catarrhines. The lineage leading to platyrrhines and, within platyrrhines, the lineage leading to Saimiri boliviensis showed a high rate of nucleotide substitutions and amino acids. Finally, several RB1 alterations associated to retinoblastoma in the human were present in several non-human primates without an apparent pathological effect.

  2. Structure of the cerebral cortex of the humpback whale, Megaptera novaeangliae (Cetacea, Mysticeti, Balaenopteridae).

    Science.gov (United States)

    Hof, Patrick R; Van der Gucht, Estel

    2007-01-01

    Cetaceans diverged from terrestrial mammals between 50 and 60 million years ago and acquired, during their adaptation to a fully aquatic milieu, many derived features, including echolocation (in odontocetes), remarkable auditory and communicative abilities, as well as a complex social organization. Whereas brain structure has been documented in detail in some odontocetes, few reports exist on its organization in mysticetes. We studied the cerebral cortex of the humpback whale (Megaptera novaeangliae) in comparison to another balaenopterid, the fin whale, and representative odontocetes. We observed several differences between Megaptera and odontocetes, such as a highly clustered organization of layer II over the occipital and inferotemporal neocortex, whereas such pattern is restricted to the ventral insula in odontocetes. A striking observation in Megaptera was the presence in layer V of the anterior cingulate, anterior insular, and frontopolar cortices of large spindle cells, similar in morphology and distribution to those described in hominids, suggesting a case of parallel evolution. They were also observed in the fin whale and the largest odontocetes, but not in species with smaller brains or body size. The hippocampal formation, unremarkable in odontocetes, is further diminutive in Megaptera, contrasting with terrestrial mammals. As in odontocetes, clear cytoarchitectural patterns exist in the neocortex of Megaptera, making it possible to define many cortical domains. These observations demonstrate that Megaptera differs from Odontoceti in certain aspects of cortical cytoarchitecture and may provide a neuromorphologic basis for functional and behavioral differences between the suborders as well as a reflection of their divergent evolution. c 2006 Wiley-Liss, Inc.

  3. History of arthritis and bone rarefaction evidence from paleopathology onwards.

    Science.gov (United States)

    MacLennan, W J

    1999-02-01

    Review of medical and archaeological papers reveals that osteoarthritis has been common in humans and hominids since Paleolithic times. In the British Isles, there was a particularly high prevalence in remains from Romano-British and Saxon burials suggesting that, whatever genetic factors there may have been, there was an extremely high level of physical activity. The prevalence of the condition was lower in late Medieval times; and, in at least one study of subjects from the 18th and 19th centuries, lower than in the current population. In early times, there was a reduction in bone density when there was a change from hunter gathering to agriculture which may have resulted from a change physical activity. Severe cases of osteoporosis have been identified from individual skeletons dated to the Bronze Age. In the Early Medieval period of Nubia there was progressive bone loss in women. Multiple pregnancy, prolonged lactation and dietary deficiency may have been factors. Though women from the 18th and 19th centuries experienced post-menopausal bone loss, this was not as severe as in the present day.

  4. Viable Syntax: Rethinking Minimalist Architecture

    Directory of Open Access Journals (Sweden)

    Ken Safir

    2010-03-01

    Full Text Available Hauser et al. (2002 suggest that the human language faculty emerged as a genetic innovation in the form of what is called here a ‘keystone factor’—a single, simple, formal mental capability that, interacting with the pre-existing faculties of hominid ancestors, caused a cascade of effects resulting in the language faculty in modern humans. They take Merge to be the keystone factor, but instead it is posited here that Merge is the pre-existing mechanism of thought made viable by a principle that permits relations interpretable at the interfaces to be mapped onto c-command. The simplified minimalist architecture proposed here respects the keystone factor as closely as possible, but is justified on the basis of linguistic analyses it makes available, including a relativized intervention theory applicable across Case, scope, agreement, selection and linearization, a derivation of the A/A’-distinction from Case theory, and predictions such as why in situ wh-interpretation is island-insensitive, but susceptible to intervention effects.

  5. Editorial

    Directory of Open Access Journals (Sweden)

    Alan Vince

    1999-01-01

    Full Text Available The publication of Michael Walker and Jose Gibert's paper on their important work at two palaeolithic cave sites in southern Spain and the hominid fossils found there (Walker and Gibert at al. 1998 in December 1998 brings to a close the fifth issue of Internet Archaeology. As usual, we have a varied crop of papers, ranging in date from the Lower Palaeolithic to the 18th century AD and geographically from southern Spain to northern England (Newcastle, together with reviews of two wide-ranging CDs, with very different target audiences. The first CD is the digital publication of a set of papers presented at an academic conference (reviewed by David Wheatley, Wheatley 1998 whilst the second is an introduction to numismatics published by the British Museum and designed for the general reader (reviewed by Philip de Jersey, de Jersey 1998. Can I ask all producers of digital publications who would like their work to be reviewed in the journal to contact our reviews editor, Gary Lock, or Judith Winters at the editorial office.

  6. Late Middle Pleistocene climate in southwestern China: inferences from the stratigraphic record of Panxian Dadong Cave, Guizhou

    Science.gov (United States)

    Karkanas, Panagiotis; Schepartz, Lynne A.; Miller-Antonio, Sari; Wang, Wei; Huang, Weiwen

    2008-08-01

    Panxian Dadong Cave, situated in the subtropical zone of southwestern China, preserves a fan-like sedimentary sequence close to its entrance that spans the period between MIS 8 and 5 (300-130 ka). The frequent alternation of flowstone formation, cementation, clastic deposition, and frost activity in the depositional sequence makes it ideal for reconstructing the environmental conditions prevailing during the later Middle Pleistocene on the Guizhou Plateau. Macroscopic and microscopic sedimentary analyses determine that clastic deposits were entering the cave in the form of intermittent cohesive debris flows and sheetflows during cold and relatively dry climatic conditions when vegetation cover was reduced. Interlayered impure flowstones were forming during wetter phases but still under glacial conditions. Seasonally freezing temperatures are deduced from the frequent occurrence of cycles of well-developed freeze-thaw features affecting both the clastic parts of the sequence and the flowstones as they were deposited. The described depositional processes were responsible for lateral redistribution on the fan surface of bone remains and lithic artifacts that were accumulating on the surface as a result of hominid activities. During the intervening interglacial stages (MIS 7 and possibly MIS 5) clastic deposition was considerably reduced and only thin flowstone caps and weathering manganese-iron crusts were forming. It is suggested that precipitation was much higher during glacial intervals than interglacials under a predominantly cold climate. Dadong Cave provides a good example of very cold and wet climatic conditions during glacials in the subtropics of East Asia.

  7. The adaptive nature of the human neurocognitive architecture: an alternative model.

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    La Cerra, P; Bingham, R

    1998-09-15

    The model of the human neurocognitive architecture proposed by evolutionary psychologists is based on the presumption that the demands of hunter-gatherer life generated a vast array of cognitive adaptations. Here we present an alternative model. We argue that the problems inherent in the biological markets of ancestral hominids and their mammalian predecessors would have required an adaptively flexible, on-line information-processing system, and would have driven the evolution of a functionally plastic neural substrate, the neocortex, rather than a confederation of evolutionarily prespecified social cognitive adaptations. In alignment with recent neuroscientific evidence, we suggest that human cognitive processes result from the activation of constructed cortical representational networks, which reflect probabilistic relationships between sensory inputs, behavioral responses, and adaptive outcomes. The developmental construction and experiential modification of these networks are mediated by subcortical circuitries that are responsive to the life history regulatory system. As a consequence, these networks are intrinsically adaptively constrained. The theoretical and research implications of this alternative evolutionary model are discussed.

  8. Survival of the fattest: fat babies were the key to evolution of the large human brain.

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    Cunnane, Stephen C; Crawford, Michael A

    2003-09-01

    In the past 2 million years, the hominid lineage leading to modern humans evolved significantly larger and more sophisticated brains than other primates. We propose that the modern human brain was a product of having first evolved fat babies. Hence, the fattest (infants) became, mentally, the fittest adults. Human babies have brains and body fat each contributing to 11-14% of body weight, a situation which appears to be unique amongst terrestrial animals. Body fat in human babies provides three forms of insurance for brain development that are not available to other land-based species: (1) a large fuel store in the form of fatty acids in triglycerides; (2) the fatty acid precursors to ketone bodies which are key substrates for brain lipid synthesis; and (3) a store of long chain polyunsaturated fatty acids, particularly docosahexaenoic acid, needed for normal brain development. The triple combination of high fuel demands, inability to import cholesterol or saturated fatty acids, and dependence on docosahexaenoic acid puts the mammalian brain in a uniquely difficult situation compared with other organs and makes its expansion in early humans all the more remarkable. We believe that fresh- and salt-water shorelines provided a uniquely rich, abundant and accessible food supply, and the only viable environment for evolving both body fat and larger brains in human infants.

  9. Psychosis: a costly by-product of social brain evolution in Homo sapiens.

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    Burns, Jonathan Kenneth

    2006-07-01

    The plethora of varied and often conflictual research evidence on the functional psychoses calls for a unifying explanatory framework. An evolutionary framework is appropriate in view of the paradoxical epidemiology of the disorders. Evolutionary models that rely on balanced polymorphism or group selection models are not supported by the evidence. Rather, a hypothesis is presented arguing that the spectrum of psychoses should be regarded as a costly by-product of social brain evolution in Homo sapiens. Under social selective pressures, hominid ancestors evolved a sophisticated neural network supporting social cognition and adaptive interpersonal behaviour--this is termed the 'social brain'. The functional psychoses (and schizophrenia in particular) are characterised by functional and structural deficits in these fronto-temporal and fronto-parietal circuits; hence the epithet 'social brain disorders' is fitting. I argue that accumulating evidence for an evolved social brain calls for a new philosophy of mind; a philosophy focussed on the social and interpersonal nature of human experience and derived from the philosophies of Fromm, Heidegger and Merleau-Ponty. Such a paradigm shift would aid modern neuroscience in finally abandoning Cartesian dualism and would guide psychiatry towards an integrated and 'socio-neurologically' embedded understanding of mental disorders.

  10. The global diversity of eating patterns: human nutritional health in comparative perspective.

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    Leonard, William R

    2014-07-01

    This paper draws on comparative data to explore the evolutionary origins of human nutritional needs and the diverse strategies used by human populations to meet those needs. Humans have evolved distinctive nutritional characteristics associated with the high metabolic costs of our large brains. The evolution of larger hominid brain size necessitated the development of foraging strategies that both provided high quality foods, and required larger ranges and higher levels of energy expenditure. Over time, human subsistence strategies have become ever more efficient in obtaining energy with minimal time and effort. Compared to data from traditional, subsistence-level societies, the US diet differs markedly in its fat and carbohydrate composition, but not in its absolute energy content. Energy expenditure levels of subsistence populations are significantly higher than those of the US and other industrialized societies. These data suggest that rising rates of obesity associated with lifestyle 'modernization' is not simply the product of greater energy intakes, but rather shifts energy balance and diet composition. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Uric acid and evolution.

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    Álvarez-Lario, Bonifacio; Macarrón-Vicente, Jesús

    2010-11-01

    Uric acid (UA) is the end product of purine metabolism in humans due to the loss of uricase activity by various mutations of its gene during the Miocene epoch, which led to humans having higher UA levels than other mammals. Furthermore, 90% of UA filtered by the kidneys is reabsorbed, instead of being excreted. These facts suggest that evolution and physiology have not treated UA as a harmful waste product, but as something beneficial that has to be kept. This has led various researchers to think about the possible evolutionary advantages of the loss of uricase and the subsequent increase in UA levels. It has been argued that due to the powerful antioxidant activity of UA, the evolutionary benefit could be the increased life expectancy of hominids. For other authors, the loss of uricase and the increase in UA could be a mechanism to maintain blood pressure in times of very low salt ingestion. The oldest hypothesis associates the increase in UA with higher intelligence in humans. Finally, UA has protective effects against several neurodegenerative diseases, suggesting it could have interesting actions on neuronal development and function. These hypotheses are discussed from an evolutionary perspective and their clinical significance. UA has some obvious harmful effects, and some, not so well-known, beneficial effects as an antioxidant and neuroprotector.

  12. DNH 109: A fragmentary hominin near-proximal ulna from Drimolen, South Africa

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    Andrew Gallagher

    2011-05-01

    Full Text Available We describe a fragmentary, yet significant, diminutive proximal ulna (DNH 109 from the Lower Pleistocene deposits of Drimolen, Republic of South Africa. On the basis of observable morphology and available comparative metrics, DNH 109 is definitively hominin and is the smallest African Plio-Pleistocene australopith ulna yet recovered. Mediolateral and anteroposterior dimensions of the proximal diaphysis immediately distal to the m. brachialis sulcus in DNH 109 yield an elliptical area (π/4 *m-l*a-p that is smaller than the A.L. 333-38 Australopithecus afarensis subadult from Hadar. Given the unusually broad mediolateral/anteroposterior diaphyseal proportions distal to the brachialis sulcus, the osseous development of the medial and lateral borders of the sulcus, and the overall size of the specimen relative to comparative infant, juvenile, subadult and adult comparative hominid ulnae (Gorilla, Pan and Homo, it is probable that DNH 109 samples an australopith of probable juvenile age at death. As a result of the fragmentary state of preservation and absence of association with taxonomically diagnostic craniodental remains, DNH 109 cannot be provisionally assigned to any particular hominin genus (Paranthropus or Homo at present. Nonetheless, DNH 109 increases our known sample of available Plio-Pleistocene subadult early hominin postcrania.

  13. THE SIGNIFICANCE OF THE SUBPLATE FOR EVOLUTION AND DEVELOPMENTAL PLASTICITY OF THE HUMAN BRAIN

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    MILOS eJUDAS

    2013-08-01

    Full Text Available The human life-history is characterized by long development and introduction of new developmental stages, such as childhood and adolescence. The developing brain had important role in these life-history changes because it is expensive tissue which uses up to 80% of resting metabolic rate in the newborn and continues to use almost 50% of it during the first 5 postnatal years. Our hominid ancestors managed to lift-up metabolic constraints to increase in brain size by several interrelated ecological, behavioral and social adaptations, such as dietary change, invention of cooking, creation of family-bonded reproductive units, and life-history changes. This opened new vistas for the developing brain, because it became possible to metabolically support transient patterns of brain organization as well as developmental brain plasticity for much longer period and with much greater number of neurons and connectivity combinations in comparison to apes. This included the shaping of cortical connections through the interaction with infant's social environment, which probably enhanced typically human evolution of language, cognition and self-awareness. In this review, we propose that the transient subplate zone and its postnatal remnant (interstitial neurons of the gyral white matter probably served as the main playground for evolution of these developmental shifts, and describe various features that makes human subplate uniquely positioned to have such a role in comparison with other primates.

  14. Sherwood Washburn's New physical anthropology: rejecting the "religion of taxonomy".

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    Mikels-Carrasco, Jessica

    2012-01-01

    Many physical anthropologists and nearly all of those studying primatology today can trace their academic genealogy to Sherwood Larned Washburn. His New physical anthropology, fully articulated in a 1951 paper, proposed that the study of hominid evolution must link understandings of form, function, and behavior along with the environment in order most accurately to reconstruct the evolution of our ancestors. This shift of concentration from strictly analyzing fossil remains to what Washburn termed adaptive complexes challenged not only Washburn's predecessors, but also led Washburn to critique the very system of academia within which he worked. Collaboration across multiple disciplines, linking the four fields of anthropology in order to understand humans and application of our understandings of human evolution to the betterment of society, are the hallmarks of Washburnian anthropology. In this paper I will explore how Washburn's New physical anthropology led him to not only change the research direction in physical anthropology, but also to challenge the academia within which he worked. I will conclude by reflecting on the prospects of continuing to practice Washburnian Anthropology.

  15. An evaluation of dental radiograph accuracy in the measurement of enamel thickness.

    Science.gov (United States)

    Grine, F E; Stevens, N J; Jungers, W L

    2001-12-01

    Many studies have employed lateral radiographs to measure the thickness of tooth enamel in recent human and fossil hominid samples, but the accuracy of measurements obtained by this technique has not been assessed. In this study, 20 isolated human maxillary permanent molars were radiographed using the parallel film technique. The crowns were then sectioned longitudinally through the tips of the buccal cusps. Measurements of enamel cap area, and of linear enamel thickness in the occlusal basin and over the metacone apex, were made from the radiographs and corresponding sectioned surfaces. Comparisons of the two sets of values revealed that radiographs generally overestimated enamel thickness but there was considerable variability in the error by which measurements from radiographs either under- or overestimated the true value. Lateral radiographs may provide a rough visual impression of whether a tooth has thin or thick enamel but they do not generally provide for accurate measurement of enamel thickness. Quantitative data on enamel thickness from studies that have employed lateral radiographs should be viewed with circumspection.

  16. Disproportionate Cochlear Length in Genus Homo Shows a High Phylogenetic Signal during Apes' Hearing Evolution.

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    J Braga

    Full Text Available Changes in lifestyles and body weight affected mammal life-history evolution but little is known about how they shaped species' sensory systems. Since auditory sensitivity impacts communication tasks and environmental acoustic awareness, it may have represented a deciding factor during mammal evolution, including apes. Here, we statistically measure the influence of phylogeny and allometry on the variation of five cochlear morphological features associated with hearing capacities across 22 living and 5 fossil catarrhine species. We find high phylogenetic signals for absolute and relative cochlear length only. Comparisons between fossil cochleae and reconstructed ape ancestral morphotypes show that Australopithecus absolute and relative cochlear lengths are explicable by phylogeny and concordant with the hypothetized ((Pan,Homo,Gorilla and (Pan,Homo most recent common ancestors. Conversely, deviations of the Paranthropus oval window area from these most recent common ancestors are not explicable by phylogeny and body weight alone, but suggest instead rapid evolutionary changes (directional selection of its hearing organ. Premodern (Homo erectus and modern human cochleae set apart from living non-human catarrhines and australopiths. They show cochlear relative lengths and oval window areas larger than expected for their body mass, two features corresponding to increased low-frequency sensitivity more recent than 2 million years ago. The uniqueness of the "hypertrophied" cochlea in the genus Homo (as opposed to the australopiths and the significantly high phylogenetic signal of this organ among apes indicate its usefulness to identify homologies and monophyletic groups in the hominid fossil record.

  17. Exploring the Potential of Laser Ablation Carbon Isotope Analysis for Examining Ecology during the Ontogeny of Middle Pleistocene Hominins from Sima de los Huesos (Northern Spain.

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    Nuria Garcia

    Full Text Available Laser ablation of tooth enamel was used to analyze stable carbon isotope compositions of teeth of hominins, red deer, and bears from middle Pleistocene sites in the Sierra de Atapuerca in northern Spain, to investigate the possibility that this technique could be used as an additional tool to identify periods of physiological change that are not detectable as changes in tooth morphology. Most of the specimens were found to have minimal intra-tooth variation in carbon isotopes (< 2.3‰, suggesting isotopically uniform diets through time and revealing no obvious periods of physiological change. However, one of the two sampled hominin teeth displayed a temporal carbon isotope shift (3.2‰ that was significantly greater than observed for co-occurring specimens. The δ13C value of this individual averaged about -16‰ early in life, and -13‰ later in life. This isotopic change occurred on the canine crown about 4.2 mm from the root, which corresponds to an approximate age of two to four years old in modern humans. Our dataset is perforce small owing to the precious nature of hominid teeth, but it demonstrates the potential utility of the intra-tooth isotope profile method for extracting ontogenetic histories of human ancestors.

  18. A new species of Nyanzachoerus (Cetartiodactyla: Suidae from the late Miocene Toros-Ménalla, Chad, central Africa.

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    Jean-Renaud Boisserie

    Full Text Available During the latest Miocene and the early Pliocene, tetraconodontine suids were the most predominant large omnivorous mammals in Africa. Yet, new species were often identified on the grounds of limited evidence, a situation impacting their value for biochronological correlations as well as for environmental and biogeographical reconstructions. The description of the most abundant known collection of craniodental remains attributed to the tetraconodontine Nyanzachoerus helps to improve this situation. These specimens were collected in the upper Miocene deposits at Toros-Ménalla, northern Chad, central Africa, by the Mission Paléoanthropologique Franco-Tchadienne. We compared them with Nyanzachoerus from eastern and southern Africa, using extant species as a reference for patterns of morphological variation. Thanks to a large sample of observations, our work focused as much on craniomandibular morphology as on dental morphology and metrics (improved by an index scoring for the complexity of distal third molars and a detailed investigation of premolar-molar ratios. We recognized two taxa at Toros-Ménalla: Nyanzachoerus khinzir nov. sp. and Ny. cf. australis. We also revised the taxonomic status for other species, including: the restriction of Ny. syrticus to its holotype specimen from Sahabi (Libya, the resurrection of the nomen Ny. tulotos, and the synonymy of Ny. kuseralensis with Ny. waylandi. At Toros-Ménalla, Ny. khinzir was the only suid coexisting with the anthracotheriid Libycosaurus and the hominid Sahelanthropus, whereas Ny. cf. australis was associated with a different, probably younger faunal context. Nyanzachoerus. khinzir, which probably had a diversified diet, supports a latest Miocene biogeographical distinction between central Africa and eastern Africa.

  19. Shared Pattern of Endocranial Shape Asymmetries among Great Apes, Anatomically Modern Humans, and Fossil Hominins

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    Balzeau, Antoine; Gilissen, Emmanuel; Grimaud-Hervé, Dominique

    2012-01-01

    Anatomical asymmetries of the human brain are a topic of major interest because of their link with handedness and cognitive functions. Their emergence and occurrence have been extensively explored in human fossil records to document the evolution of brain capacities and behaviour. We quantified for the first time antero-posterior endocranial shape asymmetries in large samples of great apes, modern humans and fossil hominins through analysis of “virtual” 3D models of skull and endocranial cavity and we statistically test for departures from symmetry. Once based on continuous variables, we show that the analysis of these brain asymmetries gives original results that build upon previous analysis based on discrete traits. In particular, it emerges that the degree of petalial asymmetries differs between great apes and hominins without modification of their pattern. We indeed demonstrate the presence of shape asymmetries in great apes, with a pattern similar to modern humans but with a lower variation and a lower degree of fluctuating asymmetry. More importantly, variations in the position of the frontal and occipital poles on the right and left hemispheres would be expected to show some degree of antisymmetry when population distribution is considered, but the observed pattern of variation among the samples is related to fluctuating asymmetry for most of the components of the petalias. Moreover, the presence of a common pattern of significant directional asymmetry for two components of the petalias in hominids implicates that the observed traits were probably inherited from the last common ancestor of extant African great apes and Homo sapiens. These results also have important implications for the possible relationships between endocranial shape asymmetries and functional capacities in hominins. It emphasizes the uncoupling between lateralized activities, some of them well probably distinctive to Homo, and large-scale cerebral lateralization itself, which is not

  20. Motor skill for tool-use is associated with asymmetries in Broca's area and the motor hand area of the precentral gyrus in chimpanzees (Pan troglodytes).

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    Hopkins, William D; Meguerditchian, Adrien; Coulon, Olivier; Misiura, Maria; Pope, Sarah; Mareno, Mary Catherine; Schapiro, Steven J

    2017-02-01

    Among nonhuman primates, chimpanzees are well known for their sophistication and diversity of tool use in both captivity and the wild. The evolution of tool manufacture and use has been proposed as a driving mechanism for the development of increasing brain size, complex cognition and motor skills, as well as the population-level handedness observed in modern humans. Notwithstanding, our understanding of the neurological correlates of tool use in chimpanzees and other primates remains poorly understood. Here, we assessed the hand preference and performance skill of chimpanzees on a tool use task and correlated these data with measures of neuroanatomical asymmetries in the inferior frontal gyrus (IFG) and the pli-de-passage fronto-parietal moyen (PPFM). The IFG is the homolog to Broca's area in the chimpanzee brain and the PPFM is a buried gyrus that connects the pre- and post-central gyri and corresponds to the motor-hand area of the precentral gyrus. We found that chimpanzees that performed the task better with their right compared to left hand showed greater leftward asymmetries in the IFG and PPFM. This association between hand performance and PPFM asymmetry was particularly robust for right-handed individuals. Based on these findings, we propose that the evolution of tool use was associated with increased left hemisphere specialization for motor skill. We further suggest that lateralization in motor planning, rather than hand preference per se, was selected for with increasing tool manufacture and use in Hominid evolution. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Tool-use training in a species of rodent: the emergence of an optimal motor strategy and functional understanding.

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    Kazuo Okanoya

    Full Text Available BACKGROUND: Tool use is defined as the manipulation of an inanimate object to change the position or form of a separate object. The expansion of cognitive niches and tool-use capabilities probably stimulated each other in hominid evolution. To understand the causes of cognitive expansion in humans, we need to know the behavioral and neural basis of tool use. Although a wide range of animals exhibit tool use in nature, most studies have focused on primates and birds on behavioral or psychological levels and did not directly address questions of which neural modifications contributed to the emergence of tool use. To investigate such questions, an animal model suitable for cellular and molecular manipulations is needed. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrated for the first time that rodents can be trained to use tools. Through a step-by-step training procedure, we trained degus (Octodon degus to use a rake-like tool with their forelimbs to retrieve otherwise out-of-reach rewards. Eventually, they mastered effective use of the tool, moving it in an elegant trajectory. After the degus were well trained, probe tests that examined whether they showed functional understanding of the tool were performed. Degus did not hesitate to use tools of different size, colors, and shapes, but were reluctant to use the tool with a raised nonfunctional blade. Thus, degus understood the functional and physical properties of the tool after extensive training. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that tool use is not a specific faculty resulting from higher intelligence, but is a specific combination of more general cognitive faculties. Studying the brains and behaviors of trained rodents can provide insights into how higher cognitive functions might be broken down into more general faculties, and also what cellular and molecular mechanisms are involved in the emergence of such cognitive functions.

  2. Recent evolution of the NF-κB and inflammasome regulating protein POP2 in primates

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    Harton Jonathan A

    2011-03-01

    Full Text Available Abstract Background Pyrin-only protein 2 (POP2 is a small human protein comprised solely of a pyrin domain that inhibits NF-κB p65/RelA and blocks the formation of functional IL-1β processing inflammasomes. Pyrin proteins are abundant in mammals and several, like POP2, have been linked to activation or regulation of inflammatory processes. Because POP2 knockout mice would help probe the biological role of inflammatory regulation, we thus considered whether POP2 is common in the mammalian lineage. Results BLAST searches revealed that POP2 is absent from the available genomes of not only mice and rats, but those of other domestic mammals and New World monkeys as well. POP2 is however present in the genome of the primate species most closely related to humans including Pan troglodytes (chimpanzees, Macaca mulatta (rhesus macaques and others. Interestingly, chimpanzee POP2 is identical to human POP2 (huPOP2 at both the DNA and protein level. Macaque POP2 (mqPOP2, although highly conserved is not identical to the human sequence; however, both functions of the human protein are retained. Further, POP2 appears to have arisen in the mammalian genome relatively recently (~25 mya and likely derived from retrogene insertion of NLRP2. Conclusion Our findings support the hypothesis that the NLR loci of mammals, encoding proteins involved in innate and adaptive immunity as well as mammalian development, have been subject to recent and strong selective pressures. Since POP2 is capable of regulating signaling events and processes linked to innate immunity and inflammation, its presence in the genomes of hominids and Old World primates further suggests that additional regulation of these signals is important in these species.

  3. Biospheric Cooling and the Emergence of Intelligence

    Science.gov (United States)

    Schwartzman, David; Middendorf, George

    The long-term cooling history of the Earth's biosphere implies a temperature constraint on the timing of major events in biologic evolution, e.g., emergence of cyanobacteria, eucaryotes and Metazoa apparently occurred at times when temperatures were near their upper growth limits. Could biospheric cooling also have been a necessary condition for the emergence of veterbrates and their encephalization? The upper temperature limit for vertebrate growth is about 10 degrees below the limit for Metazoa (50 degrees C). Heterothermy followed by full homeothermy was likely a necessary condition for greater encephalization because of the energy requirement of larger brains. The temperature differential between an animal and a cooler environment, all other factors equal, will increase the efficiency of heat loss from the brain, but too large a differential will shift metabolic energy away from the brain to the procurement of food. Encephalization has also entailed the evolution of internal cooling mechanisms to avoid overheating the brain. The two periods of pronounced Phanerozoic cooling, the PermoCarboniferous and late Cenozoic, corresponded to the emergence of mammal-like reptiles and hominids respectively, with a variety of explanations offered for the apparent link. The origin of highly encephalized whales, dolphins and porpoises occurred with the drop in ocean temperatures 25-30 mya. Of course, other possible paths to encephalization are conceivable, with radically different solutions to the problem of heat dissipation. But the intrinsic requirements for information processing capacity necessary for intelligence suggest our terrestrial pattern may resemble those of alien biospheres given similar histories.

  4. Brains, tools, innovation and biogeography in crows and ravens

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    Jønsson Knud A

    2012-05-01

    Full Text Available Abstract Background Crows and ravens (Passeriformes: Corvus are large-brained birds with enhanced cognitive abilities relative to other birds. They are among the few non-hominid organisms on Earth to be considered intelligent and well-known examples exist of several crow species having evolved innovative strategies and even use of tools in their search for food. The 40 Corvus species have also been successful dispersers and are distributed on most continents and in remote archipelagos. Results This study presents the first molecular phylogeny including all species and a number of subspecies within the genus Corvus. We date the phylogeny and determine ancestral areas to investigate historical biogeographical patterns of the crows. Additionally, we use data on brain size and a large database on innovative behaviour and tool use to test whether brain size (i explains innovative behaviour and success in applying tools when foraging and (ii has some correlative role in the success of colonization of islands. Our results demonstrate that crows originated in the Palaearctic in the Miocene from where they dispersed to North America and the Caribbean, Africa and Australasia. We find that relative brain size alone does not explain tool use, innovative feeding strategies and dispersal success within crows. Conclusions Our study supports monophyly of the genus Corvus and further demonstrates the direction and timing of colonization from the area of origin in the Palaearctic to other continents and archipelagos. The Caribbean was probably colonized from North America, although some North American ancestor may have gone extinct, and the Pacific was colonized multiple times from Asia and Australia. We did not find a correlation between relative brain size, tool use, innovative feeding strategies and dispersal success. Hence, we propose that all crows and ravens have relatively large brains compared to other birds and thus the potential to be innovative if

  5. The Edge of Human? The Problem with the Posthuman as the 'Beyond'.

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    Lawrence, David R

    2017-03-01

    This article asks whether enhancement can truly lead to something beyond humanity, or whether it is, itself, an inherently human act. The 'posthuman' is an uncertain proposition. What, exactly, would one be? Many commentators suggest it to be an endpoint for the use of enhancement technologies, yet few choose to codify the term outright; which frequently leads to unnecessary confusion. Characterizing and contextualizing the term, particularly its more novel uses, is therefore a valuable enterprise. The abuse of the term 'Human', especially in the context of the enhancement debate and the myriad meanings ascribed to it, could give 'posthuman' very different slants depending on one's assumptions. There are perhaps three main senses in which the term 'human' is employed: the biological, the moral, and the self-idealizing. In the first of these, 'human' is often conflated with Homo sapiens, and used interchangeably to denote species; in the second, 'human' (or 'humanity') generally refers to a community of beings which qualify as having a certain moral value; and the third, the self-idealizing sense, is more descriptive; a label denoting the qualities that make us who we are as beings, or 'what matters about those who matter'. So, what might enhancement make us? A novel species or genus of hominid? Or, perhaps, a morally more valuable being than a regular human? Of course, there's a third option: that a posthuman is a being which embodies our self-ideal more successfully than we do ourselves - one 'more human than human'. Which to choose? © 2016 John Wiley & Sons Ltd.

  6. Risk and the evolution of human exchange

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    Kaplan, Hillard S.; Schniter, Eric; Smith, Vernon L.; Wilson, Bart J.

    2012-01-01

    Compared with other species, exchange among non-kin is a hallmark of human sociality in both the breadth of individuals and total resources involved. One hypothesis is that extensive exchange evolved to buffer the risks associated with hominid dietary specialization on calorie dense, large packages, especially from hunting. ‘Lucky’ individuals share food with ‘unlucky’ individuals with the expectation of reciprocity when roles are reversed. Cross-cultural data provide prima facie evidence of pair-wise reciprocity and an almost universal association of high-variance (HV) resources with greater exchange. However, such evidence is not definitive; an alternative hypothesis is that food sharing is really ‘tolerated theft’, in which individuals possessing more food allow others to steal from them, owing to the threat of violence from hungry individuals. Pair-wise correlations may reflect proximity providing greater opportunities for mutual theft of food. We report a laboratory experiment of foraging and food consumption in a virtual world, designed to test the risk-reduction hypothesis by determining whether people form reciprocal relationships in response to variance of resource acquisition, even when there is no external enforcement of any transfer agreements that might emerge. Individuals can forage in a high-mean, HV patch or a low-mean, low-variance (LV) patch. The key feature of the experimental design is that individuals can transfer resources to others. We find that sharing hardly occurs after LV foraging, but among HV foragers sharing increases dramatically over time. The results provide strong support for the hypothesis that people are pre-disposed to evaluate gains from exchange and respond to unsynchronized variance in resource availability through endogenous reciprocal trading relationships. PMID:22513855

  7. IODP Site 1476: 7.5 Million Year Record of Southeast African Climate

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    Cantu, K.; Norris, R. D.

    2017-12-01

    The primary focus of IODP Expedition 361 was Southeast African Climate. Site 1476 in the northern Mozambique Channel yielded a sediment record going back roughly 7.6 million years, a time frame particularly interesting due to its relevance to hominid evolution. Previous paleoclimate studies from the region have included lake sediments and soil carbonate isotopes, which have been interpreted as showing a long-term trend toward increasing aridity. Lake Malawi records from the last 1.3 million years show a change during the Mid-Pleistocene Transition (MPT) from high frequency variability and generally lower lake levels to higher amplitude variability and higher lake levels punctuated by long, severe droughts resulting in extreme and long-lasting low-stands. Site 1476 cores were scanned using X-Ray Fluorescence (XRF), which gives semi-quantitative elemental abundances. Elemental abundance ratios are used as proxies for a variety of climate-related signals, such as changes in weathering rates, the nature of terrigenous material, and grain size. Looking at the site's Fe/Ca, K/Ca, and Rb/Zr ratios, the period of 4.5 to about 1.5 million years ago shows higher terrigenous flux, higher clay flux, and a smaller grain size respectively than most of the previous 3 million years, followed by a steep decline before the MPT, before transitioning to a pattern of high amplitude oscillations post-MPT. These higher amplitude oscillations seem to correspond to Lake Malawi low stands in the post-MPT period, suggesting that the higher flux of terrigenous material to site 1476 is due to higher aridity resulting in lower vegetative cover. This data also point to high climate variability in the last million years, likely contributing to the evolution and ecological adaptability of our species.

  8. Knuckle-walking anteater: a convergence test of adaptation for purported knuckle-walking features of African Hominidae.

    Science.gov (United States)

    Orr, Caley M

    2005-11-01

    distal radius in the hominin lineage might be indicative of a knuckle-walking ancestry for bipedal hominins if interpreted within the biomechanical and phylogenetic context of hominid locomotor evolution. Copyright 2005 Wiley-Liss, Inc

  9. New evidence for diet and niche partitioning in Rudapithecus and Anapithecus from Rudabánya, Hungary.

    Science.gov (United States)

    Deane, Andrew S; Nargolwalla, Mariam C; Kordos, László; Begun, David R

    2013-12-01

    Rudabánya is rare among Eurasian Miocene fossil primate localities in preserving both a hominid and pliopithecoid, and as such provides the unique opportunity to reconstruct the nature of sympatry and niche partitioning in these taxa. Rudapithecus and Anapithecus have similar locomotor and positional behavior and overlapping body mass ranges. While prior analyses of molar occlusal anatomy and microwear identify Rudapithecus as a soft-object frugivore, reconstructing the dietary behavior of Anapithecus has been more problematic. This taxon has been interpreted to be more folivorous by some, and more frugivorous by others. Here, we use high-resolution polynomial curve fitting (HR-PCF) to quantify and evaluate the mesiodistal and cervico-incisal curvatures of the incisor crowns of Rudapithecus and Anapithecus to identify diet-specific morphological variation in these taxa. Results are consistent with the interpretation that Anapithecus and Rudapithecus were primarily frugivorous and had diets that included similar resource types. However, Anapithecus may have consumed greater amounts of foliage, similar to extant mixed folivore-frugivores (i.e., Gorilla gorilla gorilla, Symphalangus syndactylus), while Rudapithecus generated elevated compressive loads in the incisor region consistent with a specialized role for the anterior dentition in food processing (i.e., removal of tough protective fruit pericarps). We interpret these findings in light of the paleoecology at Rudabánya and conclude that, if these taxa were indeed sympatric, Anapithecus may have used additional leaf consumption as a seasonal fallback resource to avoid direct competition with Rudapithecus. Conversely, Rudapithecus may have relied on less preferred and harder fruiting resources as a seasonal fallback resource during periods of fruit scarcity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Osteocalcin protein sequences of Neanderthals and modern primates.

    Science.gov (United States)

    Nielsen-Marsh, Christina M; Richards, Michael P; Hauschka, Peter V; Thomas-Oates, Jane E; Trinkaus, Erik; Pettitt, Paul B; Karavanic, Ivor; Poinar, Hendrik; Collins, Matthew J

    2005-03-22

    We report here protein sequences of fossil hominids, from two Neanderthals dating to approximately 75,000 years old from Shanidar Cave in Iraq. These sequences, the oldest reported fossil primate protein sequences, are of bone osteocalcin, which was extracted and sequenced by using MALDI-TOF/TOF mass spectrometry. Through a combination of direct sequencing and peptide mass mapping, we determined that Neanderthals have an osteocalcin amino acid sequence that is identical to that of modern humans. We also report complete osteocalcin sequences for chimpanzee (Pan troglodytes) and gorilla (Gorilla gorilla gorilla) and a partial sequence for orangutan (Pongo pygmaeus), all of which are previously unreported. We found that the osteocalcin sequences of Neanderthals, modern human, chimpanzee, and orangutan are unusual among mammals in that the ninth amino acid is proline (Pro-9), whereas most species have hydroxyproline (Hyp-9). Posttranslational hydroxylation of Pro-9 in osteocalcin by prolyl-4-hydroxylase requires adequate concentrations of vitamin C (l-ascorbic acid), molecular O(2), Fe(2+), and 2-oxoglutarate, and also depends on enzyme recognition of the target proline substrate consensus sequence Leu-Gly-Ala-Pro-9-Ala-Pro-Tyr occurring in most mammals. In five species with Pro-9-Val-10, hydroxylation is blocked, whereas in gorilla there is a mixture of Pro-9 and Hyp-9. We suggest that the absence of hydroxylation of Pro-9 in Pan, Pongo, and Homo may reflect response to a selective pressure related to a decline in vitamin C in the diet during omnivorous dietary adaptation, either independently or through the common ancestor of these species.

  11. Learning by heart: cultural patterns in the faunal processing sequence during the middle pleistocene.

    Directory of Open Access Journals (Sweden)

    Ruth Blasco

    Full Text Available Social learning, as an information acquisition process, enables intergenerational transmission and the stabilisation of cultural forms, generating and sustaining behavioural traditions within human groups. Archaeologically, such social processes might become observable by identifying repetitions in the record that result from the execution of standardised actions. From a zooarchaeological perspective, the processing and consumption of carcasses may be used to identify these types of phenomena at the sites. To investigate this idea, several faunal assemblages from Bolomor Cave (Valencia, Spain, MIS 9-5e and Gran Dolina TD10-1 (Burgos, Spain, MIS 9 were analysed. The data show that some butchery activities exhibit variability as a result of multiple conditioning factors and, therefore, the identification of cultural patterns through the resulting cut-marks presents additional difficulties. However, other activities, such as marrow removal by means of intentional breakage, seem to reflect standardised actions unrelated to the physical characteristics of the bones. The statistical tests we applied show no correlation between the less dense areas of the bones and the location of impacts. Comparison of our experimental series with the archaeological samples indicates a counter-intuitive selection of the preferred locus of impact, especially marked in the case of Bolomor IV. This fact supports the view that bone breakage was executed counter-intuitively and repetitively on specific sections because it may have been part of an acquired behavioural repertoire. These reiterations differ between levels and sites, suggesting the possible existence of cultural identities or behavioural predispositions dependant on groups. On this basis, the study of patterns could significantly contribute to the identification of occupational strategies and organisation of the hominids in a territory. In this study, we use faunal data in identifying the mechanics of

  12. A bivariate approach to the widening of the frontal lobes in the genus Homo.

    Science.gov (United States)

    Bruner, Emiliano; Holloway, Ralph L

    2010-02-01

    Within the genus Homo, the most encephalized taxa (Neandertals and modern humans) show relatively wider frontal lobes than either Homo erectus or australopithecines. The present analysis considers whether these changes are associated with a single size-based or allometric pattern (positive allometry of the width of the anterior endocranial fossa) or with a more specific and non-allometric pattern. The relationship between hemispheric length, maximum endocranial width, and frontal width at Broca's area was investigated in extant and extinct humans. Our results do not support positive allometry for the frontal lobe's width in relation to the main endocranial diameters within modern humans (Homo sapiens). Also, the correlation between frontal width and hemispheric length is lower than the correlation between frontal width and parieto-temporal width. When compared with the australopithecines, the genus Homo could have experienced a non-allometric widening of the brain at the temporo-parietal areas, which is most evident in Neandertals. Modern humans and Neandertals also display a non-allometric widening of the anterior endocranial fossa at the Broca's cap when compared with early hominids, again more prominent in the latter group. Taking into account the contrast between the intra-specific patterns and the between-species differences, the relative widening of the anterior fossa can be interpreted as a definite evolutionary character instead of a passive consequence of brain size increase. This expansion is most likely associated with correspondent increments of the underlying neural mass, or at least with a geometrical reallocation of the frontal cortical volumes. Although different structural changes of the cranial architecture can be related to such variations, the widening of the frontal areas is nonetheless particularly interesting when some neural functions (like language or working memory, decision processing, etc.) and related fronto-parietal cortico

  13. Comparing primate crania: The importance of fossils.

    Science.gov (United States)

    Fleagle, John G; Gilbert, Christopher C; Baden, Andrea L

    2016-10-01

    Extant primate crania represent a small subset of primate crania that have existed. The main objective here is to examine how the inclusion of fossil crania changes our understanding of primate cranial diversity relative to analyses of extant primates. We hypothesize that fossil taxa will change the major axes of cranial shape, occupy new areas of morphospace, change the relative diversity of major primate clades, and fill in notable gaps separating major primate taxa/clades. Eighteen 3D landmarks were collected on 157 extant and fossil crania representing 90 genera. Data were subjected to a Generalized Procrustes Analysis then principal components analysis. Relative diversity between clades was assessed using an F-statistic. Fossil taxa do not significantly alter major axes of cranial shape, but they do occupy unique areas of morphospace, change the relative diversity between clades, and fill in notable gaps in primate cranial evolution. Strepsirrhines remain significantly less diverse than anthropoids. Fossil hominins fill the gap in cranial morphospace between extant great apes and modern humans. The morphospace outlined by living primates largely includes that occupied by fossil taxa, suggesting that the cranial diversity of living primates generally encompasses the total diversity that has evolved in this Order. The evolution of the anthropoid cranium was a significant event allowing anthropoids to achieve significantly greater cranial diversity compared to strepsirrhines. Fossil taxa fill in notable gaps within and between clades, highlighting their transitional nature and eliminating the appearance of large morphological distances between extant taxa, particularly in the case of extant hominids. © 2016 Wiley Periodicals, Inc.

  14. Dragon's paradise lost: palaeobiogeography, evolution and extinction of the largest-ever terrestrial lizards (Varanidae.

    Directory of Open Access Journals (Sweden)

    Scott A Hocknull

    Full Text Available BACKGROUND: The largest living lizard species, Varanus komodoensis Ouwens 1912, is vulnerable to extinction, being restricted to a few isolated islands in eastern Indonesia, between Java and Australia, where it is the dominant terrestrial carnivore. Understanding how large-bodied varanids responded to past environmental change underpins long-term management of V. komodoensis populations. METHODOLOGY/PRINCIPAL FINDINGS: We reconstruct the palaeobiogeography of Neogene giant varanids and identify a new (unnamed species from the island of Timor. Our data reject the long-held perception that V. komodoensis became a giant because of insular evolution or as a specialist hunter of pygmy Stegodon. Phyletic giantism, coupled with a westward dispersal from mainland Australia, provides the most parsimonious explanation for the palaeodistribution of V. komodoensis and the newly identified species of giant varanid from Timor. Pliocene giant varanid fossils from Australia are morphologically referable to V. komodoensis suggesting an ultimate origin for V. komodoensis on mainland Australia (>3.8 million years ago. Varanus komodoensis body size has remained stable over the last 900,000 years (ka on Flores, a time marked by major faunal turnovers, extinction of the island's megafauna, the arrival of early hominids by 880 ka, co-existence with Homo floresiensis, and the arrival of modern humans by 10 ka. Within the last 2000 years their populations have contracted severely. CONCLUSIONS/SIGNIFICANCE: Giant varanids were once a ubiquitous part of Subcontinental Eurasian and Australasian faunas during the Neogene. Extinction played a pivotal role in the reduction of their ranges and diversity throughout the late Quaternary, leaving only V. komodoensis as an isolated long-term survivor. The events over the last two millennia now threaten its future survival.

  15. Validation of plaster endocast morphology through 3D CT image analysis.

    Science.gov (United States)

    Schoenemann, P Thomas; Gee, James; Avants, Brian; Holloway, Ralph L; Monge, Janet; Lewis, Jason

    2007-02-01

    A crucial component of research on brain evolution has been the comparison of fossil endocranial surfaces with modern human and primate endocrania. The latter have generally been obtained by creating endocasts out of rubber latex shells filled with plaster. The extent to which the method of production introduces errors in endocast replicas is unknown. We demonstrate a powerful method of comparing complex shapes in 3-dimensions (3D) that is broadly applicable to a wide range of paleoanthropological questions. Pairs of virtual endocasts (VEs) created from high-resolution CT scans of corresponding latex/plaster endocasts and their associated crania were rigidly registered (aligned) in 3D space for two Homo sapiens and two Pan troglodytes specimens. Distances between each cranial VE and its corresponding latex/plaster VE were then mapped on a voxel-by-voxel basis. The results show that between 79.7% and 91.0% of the voxels in the four latex/plaster VEs are within 2 mm of their corresponding cranial VEs surfaces. The average error is relatively small, and variation in the pattern of error across the surfaces appears to be generally random overall. However, inferior areas around the cranial base and the temporal poles were somewhat overestimated in both human and chimpanzee specimens, and the area overlaying Broca's area in humans was somewhat underestimated. This study gives an idea of the size of possible error inherent in latex/plaster endocasts, indicating the level of confidence we can have with studies relying on comparisons between them and, e.g., hominid fossil endocasts. Copyright 2006 Wiley-Liss, Inc.

  16. Fossil hominin ulnae and the forelimb of Paranthropus.

    Science.gov (United States)

    McHenry, Henry M; Brown, Cassandra C; McHenry, Lindsay J

    2007-10-01

    The discovery of Pan in the Middle Pleistocene deposits of the Kapthurin Formation of the Tugen Hills (McBrearty and Jablonski: Nature 437 (2005) 105-108) inspires new interest in the search for other chimpanzee fossils in the East African Rift Valley. Craniodental evidence of an eastward excursion of chimpanzee populations in the Plio-Pleistocene goes undetected in other hominin sites, but one enigmatic postcranial fossil, the Olduvai Hominid 36 ulna, has many chimp-like features. Analyses by Aiello et al. (Aiello et al.: Am J Phys Anthropol 109 (1999) 89-110) reveal that it is similar to extant Pan in some respects, but it also has unique traits not seen in other hominoid species. They refer it to Paranthropus boisei. In this study, we reassess the affinities of OH 36 using a different data set that includes more recently discovered hominin fossils including those attributed to Paranthropus. Despite its superficial resemblance to modern Pan, our results agree with those of Aiello et al. (Aiello et al.: Am J Phys Anthropol 109 (1999) 89-110) that OH 36 is distinctly different from modern chimpanzees. By default, it is reasonable to assign this specimen to P. boisei, but it is not at all similar to other ulnae referred to this genus. Ulnae attributed to Paranthropus from South Africa, Kenya, and Ethiopia are morphologically more heterogeneous than those within species of large-bodied Hominoidea. Although there are many apparent shared derived traits justifying a monophyletic Paranthropus clade, most if not all of these traits are related to a single functional complex (hypermastication) that may have evolved in parallel and thereby constituting a paraphyletic group of species. (c) 2007 Wiley-Liss, Inc.

  17. A quantitative and qualitative reanalysis of the endocast from the juvenile Paranthropus specimen l338y-6 from Omo, Ethiopia.

    Science.gov (United States)

    White, D D; Falk, D

    1999-12-01

    Based on an analysis of its endocast, Holloway (1981 Am J Phys Anthropol 53:109-118) attributed the juvenile Omo L338y-6 specimen to Australopithecus africanus (i.e., gracile australopithecines) rather than to Paranthropus (Australopithecus) boisei (robust australopithecines) favored by other workers (Rak and Howell [1978] Am J Phys Anthropol 48:345-366). Holloway's attribution was based on the specimen's (1) low cranial capacity, (2) gracile-like meningeal vessels, (3) gracile-like cerebellar hemispheres, and (4) absence of an enlarged occipital/marginal (O/M) sinus system. Recent work, however, has shown that criteria 1 and 2 are not useful for sorting gracile from robust australopithecines (Culotta [1999] Science 284:1109-1111; Falk [1993] Am J Phys Anthropol 92:81-98). In this paper, we test criterion 3 by quantifying the endocranial cerebellar and occipital morphology reproduced on the Omo L338y-6 endocast, and comparing it to seven endocasts from South and East African early hominids. Our preliminary results show that metric analysis of this specimen cannot be used to sort it preferentially with either robust or gracile australopithecines. Finally, we demonstrate that, contrary to previous reports, the Omo L338y-6 endocast reproduces an enlarged left occipital sinus (criterion 4). This observation is consistent with the original attribution of the Omo specimen to robust australopithecines (Rak and Howell [1978] Am J Phys Anthropol 48:345-366). Furthermore, if Omo L338y-6 was a robust australopithecine, this discovery extends the occurrence of an enlarged O/M sinus system to one of the earliest known paranthropines. Am J Phys Anthropol 110:399-406, 1999. Copyright 1999 Wiley-Liss, Inc.

  18. Paranthropus boisei: an example of evolutionary stasis?

    Science.gov (United States)

    Wood, B; Wood, C; Konigsberg, L

    1994-10-01

    Of the presently recognised early hominid species, Paranthropus boisei is one of the better known from the fossil record and arguably the most distinctive; the latter interpretation rests on the numbers of apparently derived characters it incorporates. The species as traditionally diagnosed is distributed across approximately one million years and is presently confined to samples from East African sites. The hypodigm has been examined for evidence of intraspecific phyletic evolution, with particular emphasis on the areas best represented in the fossil record, namely the teeth and mandible. The results of this examination of 55 mandibular and dental variables which uses the gamma test statistic for the detection of trend, and nonparametric spline regression (Loess regression) for investigating pattern and rate of temporal change, show that within Paranthropus boisei sensu stricto most evidence of temporally related morphological trends relates to the morphology of the P4 crown. There is little or no evidence of any tendency to increase in overall size through time. Fossils from the Omo Shungura Formation and West Turkana which have been recovered from a time period earlier than the P. boisei sensu stricto hypodigm resemble the latter taxon in some features, but differ from it in aspects of cranial morphology. There is insufficient fossil evidence of the earlier taxon to tell whether it changes through time, but when trends of 47 mandibular and dental variables are assessed across the combined East African "robust" australopithecine sample, there is evidence for a relatively abrupt change around 2.2-2.3 Myr in approximately 25% of the dental and mandibular remains. Some of these changes correspond with the temporal trends within P. boisei sensu stricto, but others, such as mandible height, do not. If the earlier material is ancestral to P. boisei sensu stricto, evidence from the teeth and jaws is consistent with a punctuated origin for the latter taxon.

  19. Climate-mediated shifts in Neandertal subsistence behaviors at Pech de l'Azé IV and Roc de Marsal (Dordogne Valley, France).

    Science.gov (United States)

    Hodgkins, Jamie; Marean, Curtis W; Turq, Alain; Sandgathe, Dennis; McPherron, Shannon J P; Dibble, Harold

    2016-07-01

    Neandertals disappeared from Europe just after 40,000 years ago. Some hypotheses ascribe this to numerous population crashes associated with glacial cycles in the late Pleistocene. The goal of this paper is to test the hypothesis that glacial periods stressed Neandertal populations. If cold climates stressed Neandertals, their subsistence behaviors may have changed-requiring intensified use of prey through more extensive nutrient extraction from faunal carcasses. To test this, an analysis of Neandertal butchering was conducted on medium sized bovid/cervid remains composed of predominately red deer (Cervus elaphus), reindeer (Rangifer tarandus), and roe deer (Capreolus caprelous) deposited during global warm and cold phases from two French sites: Pech de l'Azé IV (Pech IV, Bordes' excavation) and Roc de Marsal (RDM). Analysis of surface modification on high survival long bones and proximal and middle phalanges demonstrates that skeletal elements excavated from the cold levels (RDM Level 4, Pech IV Level I2) at each cave have more cut marks and percussion marks than elements from the warm levels (RDM Level 9, Pech IV Level Y-Z) after controlling for fragment size. At both sites, epiphyseal fragments are rare, and although this pattern can result from carnivore consumption, carnivore tooth marks are almost nonexistent (climate, but may have been a general Neandertal behavioral characteristic, suggesting that these hominids were regularly on the edge of sufficient nutrient availability even during interglacials. Overall, the faunal assemblages from Roc de Marsal and Pech IV provide some support for the hypothesis that Neandertals were processing faunal remains more heavily during glacial periods, suggesting a response to increased nutritional stress during colder time periods. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Brain size and thermoregulation during the evolution of the genus Homo.

    Science.gov (United States)

    Naya, Daniel E; Naya, Hugo; Lessa, Enrique P

    2016-01-01

    Several hypotheses have been proposed to explain the evolution of an energetically costly brain in the genus Homo. Some of these hypotheses are based on the correlation between climatic factors and brain size recorded for this genus during the last millions of years. In this study, we propose a complementary climatic hypothesis that is based on the mechanistic connection between temperature, thermoregulation, and size of internal organs in endothermic species. We hypothesized that global cooling during the last 3.2 my may have imposed an increased energy expenditure for thermoregulation, which in the case of hominids could represent a driver for the evolution of an expanded brain, or at least, it could imply the relaxation of a negative selection pressure acting upon this costly organ. To test this idea, here we (1) assess variation in the energetic costs of thermoregulation and brain maintenance for the last 3.2 my, and (2) evaluate the relationship between Earth temperature and brain maintenance cost for the same period, taking into account the effects of body mass and fossil age. We found that: (1) the energetic cost associated with brain enlargement represents an important fraction (between 47.5% and 82.5%) of the increase in energy needed for thermoregulation; (2) fossil age is a better predictor of brain maintenance cost than Earth temperature, suggesting that (at least) another factor correlated with time was more relevant than ambient temperature in brain size evolution; and (3) there is a significant negative correlation between the energetic cost of brain and Earth temperature, even after accounting for the effect of body mass and fossil age. Thus, our results expand the current energetic framework for the study of brain size evolution in our lineage by suggesting that a fall in Earth temperature during the last millions of years may have facilitated brain enlargement. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Learning by Heart: Cultural Patterns in the Faunal Processing Sequence during the Middle Pleistocene

    Science.gov (United States)

    Blasco, Ruth; Rosell, Jordi; Domínguez-Rodrigo, Manuel; Lozano, Sergi; Pastó, Ignasi; Riba, David; Vaquero, Manuel; Peris, Josep Fernández; Arsuaga, Juan Luis; de Castro, José María Bermúdez; Carbonell, Eudald

    2013-01-01

    Social learning, as an information acquisition process, enables intergenerational transmission and the stabilisation of cultural forms, generating and sustaining behavioural traditions within human groups. Archaeologically, such social processes might become observable by identifying repetitions in the record that result from the execution of standardised actions. From a zooarchaeological perspective, the processing and consumption of carcasses may be used to identify these types of phenomena at the sites. To investigate this idea, several faunal assemblages from Bolomor Cave (Valencia, Spain, MIS 9-5e) and Gran Dolina TD10-1 (Burgos, Spain, MIS 9) were analysed. The data show that some butchery activities exhibit variability as a result of multiple conditioning factors and, therefore, the identification of cultural patterns through the resulting cut-marks presents additional difficulties. However, other activities, such as marrow removal by means of intentional breakage, seem to reflect standardised actions unrelated to the physical characteristics of the bones. The statistical tests we applied show no correlation between the less dense areas of the bones and the location of impacts. Comparison of our experimental series with the archaeological samples indicates a counter-intuitive selection of the preferred locus of impact, especially marked in the case of Bolomor IV. This fact supports the view that bone breakage was executed counter-intuitively and repetitively on specific sections because it may have been part of an acquired behavioural repertoire. These reiterations differ between levels and sites, suggesting the possible existence of cultural identities or behavioural predispositions dependant on groups. On this basis, the study of patterns could significantly contribute to the identification of occupational strategies and organisation of the hominids in a territory. In this study, we use faunal data in identifying the mechanics of intergenerational

  2. Nonocclusal dental microwear analysis of 300,000-year-old Homo heilderbergensis teeth from Sima de los Huesos (Sierra de Atapuerca, Spain).

    Science.gov (United States)

    Pérez-Pérez, A; Bermúdez De Castro, J M; Arsuaga, J L

    1999-04-01

    Casts of nonocclusal enamel surfaces of 190 teeth from the Middle Pleistocene site of Sima de los Huesos have been micrographed by scanning electron microscopy. Microscopic analyses of striation density and length by orientation show distinct patterns of intrapopulation variability. Significant differences in the number and length of the striations by orientation are found between maxillary and mandibular teeth. This probably reflects differences in the mechanical forces involved in the process of chewing food. Significant differences are present between isolated and in situ teeth that could be caused by postdepositional processes differentially affecting the isolated teeth. In addition, a distinct and very unusual striation pattern is observed in a sample of teeth that can be explained only by a strong nondietary, most probably postmortem abrasion of the enamel surfaces. These teeth have a very high density of scratches, shorter in length than those found on other teeth, that are not indicative of dietary habits. No known depositional process may account for the presence of such postmortem wear since heavy transportation of materials within the clayish sediments has been discarded for the site. Despite this, a characteristic dietary striation pattern can be observed in most of the teeth analyzed. Most likely the diet of the Homo heidelbergensis hominids from Sima de los Huesos was highly abrasive, probably with a large dependence on hard, poorly processed plant foods, such as roots, stems, and seeds. A highly significant sex-related difference in the striation pattern can also be observed in the teeth analyzed, suggesting a differential consistency in the foods eaten by females and males.

  3. Learning by heart: cultural patterns in the faunal processing sequence during the middle pleistocene.

    Science.gov (United States)

    Blasco, Ruth; Rosell, Jordi; Domínguez-Rodrigo, Manuel; Lozano, Sergi; Pastó, Ignasi; Riba, David; Vaquero, Manuel; Peris, Josep Fernández; Arsuaga, Juan Luis; de Castro, José María Bermúdez; Carbonell, Eudald

    2013-01-01

    Social learning, as an information acquisition process, enables intergenerational transmission and the stabilisation of cultural forms, generating and sustaining behavioural traditions within human groups. Archaeologically, such social processes might become observable by identifying repetitions in the record that result from the execution of standardised actions. From a zooarchaeological perspective, the processing and consumption of carcasses may be used to identify these types of phenomena at the sites. To investigate this idea, several faunal assemblages from Bolomor Cave (Valencia, Spain, MIS 9-5e) and Gran Dolina TD10-1 (Burgos, Spain, MIS 9) were analysed. The data show that some butchery activities exhibit variability as a result of multiple conditioning factors and, therefore, the identification of cultural patterns through the resulting cut-marks presents additional difficulties. However, other activities, such as marrow removal by means of intentional breakage, seem to reflect standardised actions unrelated to the physical characteristics of the bones. The statistical tests we applied show no correlation between the less dense areas of the bones and the location of impacts. Comparison of our experimental series with the archaeological samples indicates a counter-intuitive selection of the preferred locus of impact, especially marked in the case of Bolomor IV. This fact supports the view that bone breakage was executed counter-intuitively and repetitively on specific sections because it may have been part of an acquired behavioural repertoire. These reiterations differ between levels and sites, suggesting the possible existence of cultural identities or behavioural predispositions dependant on groups. On this basis, the study of patterns could significantly contribute to the identification of occupational strategies and organisation of the hominids in a territory. In this study, we use faunal data in identifying the mechanics of intergenerational

  4. The neural basis of human tool use

    Directory of Open Access Journals (Sweden)

    Guy A Orban

    2014-04-01

    Full Text Available In this review, we propose that the neural basis for the spontaneous, diversified human tool use is an area devoted to the execution and observation of tool actions, located in the left anterior supramarginal gyrus (aSMG. The aSMG activation elicited by observing tool use is typical of human subjects, as macaques show no similar activation, even after an extensive training to use tools. The execution of tool actions, as well as their observation, requires the convergence upon aSMG of inputs from different parts of the dorsal and ventral visual streams. Non semantic features of the target object may be provided by the posterior parietal cortex (PPC for tool-object interaction, paralleling the well-known PPC input to AIP for hand-object interaction. Semantic information regarding tool identity, and knowledge of the typical manner of handling the tool, could be provided by inferior and middle regions of the temporal lobe. Somatosensory feedback and technical reasoning, as well as motor and intentional constraints also play roles during the planning of tool actions and consequently their signals likewise converge upon aSMG.We further propose that aSMG may have arisen though duplication of monkey AIP and invasion of the duplicate area by afferents from PPC providing distinct signals depending on the kinematics of the manipulative action. This duplication may have occurred when Homo Habilis or Homo Erectus emerged, generating the Oldowan or Acheulean Industrial complexes respectively. Hence tool use may have emerged during hominid evolution between bipedalism and language.We conclude that humans have two parietal systems involved in tool behavior: a biological circuit for grasping objects, including tools, and an artifactual system devoted specifically to tool use. Only the latter allows humans to understand the causal relationship between tool use and obtaining the goal, and is likely to be the basis of all technological developments.

  5. Short faces, big tongues: developmental origin of the human chin.

    Directory of Open Access Journals (Sweden)

    Michael Coquerelle

    Full Text Available During the course of human evolution, the retraction of the face underneath the braincase, and closer to the cervical column, has reduced the horizontal dimension of the vocal tract. By contrast, the relative size of the tongue has not been reduced, implying a rearrangement of the space at the back of the vocal tract to allow breathing and swallowing. This may have left a morphological signature such as a chin (mental prominence that can potentially be interpreted in Homo. Long considered an autopomorphic trait of Homo sapiens, various extinct hominins show different forms of mental prominence. These features may be the evolutionary by-product of equivalent developmental constraints correlated with an enlarged tongue. In order to investigate developmental mechanisms related to this hypothesis, we compare modern 34 human infants against 8 chimpanzee fetuses, whom development of the mandibular symphysis passes through similar stages. The study sets out to test that the shared ontogenetic shape changes of the symphysis observed in both species are driven by the same factor--space restriction at the back of the vocal tract and the associated arrangement of the tongue and hyoid bone. We apply geometric morphometric methods to extensive three-dimensional anatomical landmarks and semilandmarks configuration, capturing the geometry of the cervico-craniofacial complex including the hyoid bone, tongue muscle and the mandible. We demonstrate that in both species, the forward displacement of the mental region derives from the arrangement of the tongue and hyoid bone, in order to cope with the relative horizontal narrowing of the oral cavity. Because humans and chimpanzees share this pattern of developmental integration, the different forms of mental prominence seen in some extinct hominids likely originate from equivalent ontogenetic constraints. Variations in this process could account for similar morphologies.

  6. Positive selection underlies the species-specific binding of Plasmodium falciparum RH5 to human basigin.

    Science.gov (United States)

    Forni, Diego; Pontremoli, Chiara; Cagliani, Rachele; Pozzoli, Uberto; Clerici, Mario; Sironi, Manuela

    2015-09-01

    Plasmodium falciparum, the causative agent of the deadliest form of malaria, is a member of the Laverania subgenus, which includes ape-infecting parasites. P. falciparum is thought to have originated in gorillas, although infection is now restricted to humans. Laverania parasites display remarkable host-specificity, which is partially mediated by the interaction between parasite ligands and host receptors. We analyse the evolution of BSG (basigin) and GYPA (glycophorin A) in primates/hominins, as well as of their Plasmodium-encoded ligands, PfRH5 and PfEBA175. We show that, in primates, positive selection targeted two sites in BSG (F27 and H102), both involved in PfRH5 binding. A population genetics-phylogenetics approach detected the strongest selection for the gorilla lineage: one of the positively selected sites (K191) is a major determinant of PfRH5 binding affinity. Analysis of RH5 genes indicated episodic selection on the P. falciparum branch; the positively selected W447 site is known to stabilize the interaction with human basigin. Conversely, we detect no selection in the receptor-binding region of EBA175 in the P. falciparum lineage. Its host receptor, GYPA, shows evidence of positive selection in all hominid lineages; selected codons include glycosylation sites that modulate PfEBA175 binding affinity. Data herein provide an evolutionary explanation for species-specific binding of the PfRH5-BSG ligand-receptor pair and support the hypothesis that positive selection at these genes drove the host shift leading to the emergence of P. falciparum as a human pathogen. © 2015 John Wiley & Sons Ltd.

  7. Is sporadic Alzheimer's disease a developmental disorder?

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    Arendt, Thomas; Stieler, Jens; Ueberham, Uwe

    2017-11-01

    Alzheimer's disease (AD) is a neurodegenerative disorder of higher age that specifically occurs in human. Its clinical phase, characterized by a decline in physiological, psychological, and social functioning, is preceded by a long clinically silent phase of at least several decades that might perhaps even start very early in life. Overall, key functional abilities in AD patients decline in reverse order of the development of these abilities during normal childhood and adolescence. Early symptoms of AD, thus, typically affect mental functions that have been acquired only during very recent hominid evolution and as such are specific to human. Neurofibrillar degeneration, a typical neuropathological lesion of the disease and one of the most robust pathological correlates of cognitive impairment, is rarely seen in non-primate mammals and even non-human primates hardly develop a pathology comparable to those seen in AD patients. Neurofibrillar degeneration is not randomly distributed throughout the AD brain. It preferentially affects brain areas that become increasingly predominant during the evolutionary process of encephalization. During progression of the disease, it affects cortical areas in a stereotypic sequence that inversely recapitulates ontogenetic brain development. The specific distribution of cortical pathology in AD, moreover, appears to be determined by the modular organization of the cerebral cortex which basically is a structural reflection of its ontogeny. Here, we summarize recent evidence that phylogenetic and ontogenetic dimensions of brain structure and function provide the key to our understanding of AD. More recent molecular biological studies of the potential pathogenetic role of a genomic mosaic in the brains of patients with AD might even provide arguments for a developmental origin of AD. This article is part of a series "Beyond Amyloid". © 2017 International Society for Neurochemistry.

  8. First insights into the metagenome of Egyptian mummies using next-generation sequencing.

    Science.gov (United States)

    Khairat, Rabab; Ball, Markus; Chang, Chun-Chi Hsieh; Bianucci, Raffaella; Nerlich, Andreas G; Trautmann, Martin; Ismail, Somaia; Shanab, Gamila M L; Karim, Amr M; Gad, Yehia Z; Pusch, Carsten M

    2013-08-01

    We applied, for the first time, next-generation sequencing (NGS) technology on Egyptian mummies. Seven NGS datasets obtained from five randomly selected Third Intermediate to Graeco-Roman Egyptian mummies (806 BC-124AD) and two unearthed pre-contact Bolivian lowland skeletons were generated and characterised. The datasets were contrasted to three recently published NGS datasets obtained from cold-climate regions, i.e. the Saqqaq, the Denisova hominid and the Alpine Iceman. Analysis was done using one million reads of each newly generated or published dataset. Blastn and megablast results were analysed using MEGAN software. Distinct NGS results were replicated by specific and sensitive polymerase chain reaction (PCR) protocols in ancient DNA dedicated laboratories. Here, we provide unambiguous identification of authentic DNA in Egyptian mummies. The NGS datasets showed variable contents of endogenous DNA harboured in tissues. Three of five mummies displayed a human DNA proportion comparable to the human read count of the Saqqaq permafrost-preserved specimen. Furthermore, a metagenomic signature unique to mummies was displayed. By applying a "bacterial fingerprint", discrimination among mummies and other remains from warm areas outside Egypt was possible. Due to the absence of an adequate environment monitoring, a bacterial bloom was identified when analysing different biopsies from the same mummies taken after a lapse of time of 1.5 years. Plant kingdom representation in all mummy datasets was unique and could be partially associated with their use in embalming materials. Finally, NGS data showed the presence of Plasmodium falciparum and Toxoplasma gondii DNA sequences, indicating malaria and toxoplasmosis in these mummies. We demonstrate that endogenous ancient DNA can be extracted from mummies and serve as a proper template for the NGS technique, thus, opening new pathways of investigation for future genome sequencing of ancient Egyptian individuals.

  9. Evolution of the Genus Homo

    Science.gov (United States)

    Tattersall, Ian; Schwartz, Jeffrey H.

    2009-05-01

    Definition of the genus Homo is almost as fraught as the definition of Homo sapiens. We look at the evidence for “early Homo,” finding little morphological basis for extending our genus to any of the 2.5-1.6-myr-old fossil forms assigned to “early Homo” or Homo habilis/rudolfensis. We also point to heterogeneity among “early African Homo erectus,” and the lack of apomorphies linking these fossils to the Asian Homo erectus group, a cohesive regional clade that shows some internal variation, including brain size increase over time. The first truly cosmopolitan Homo species is Homo heidelbergensis, known from Africa, Europe, and China following 600 kyr ago. One species sympatric with it included the >500-kyr-old Sima de los Huesos fossils from Spain, clearly distinct from Homo heidelbergensis and the oldest hominids assignable to the clade additionally containing Homo neanderthalensis. This clade also shows evidence of brain size expansion with time; but although Homo neanderthalensis had a large brain, it left no unequivocal evidence of the symbolic consciousness that makes our species unique. Homo sapiens clearly originated in Africa, where it existed as a physical entity before it began (also in that continent) to show the first stirrings of symbolism. Most likely, the biological underpinnings of symbolic consciousness were exaptively acquired in the radical developmental reorganization that gave rise to the highly characteristic osteological structure of Homo sapiens, but lay fallow for tens of thousands of years before being “discovered” by a cultural stimulus, plausibly the invention of language.

  10. Darwin’s legacy in South African evolutionary biology

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    S. D. Johnson

    2010-02-01

    Full Text Available In the two decades after publication of the Origin of Species, Charles Darwin facilitated the publication of numerous scientific papers by settler naturalists in South Africa. This helped to establish the strong tradition of natural history which has characterised evolutionary research in South African museums, herbaria and universities. Significant developments in the early 20th century included the hominid fossil discoveries of Raymond Dart, Robert Broom, and others, but there was otherwise very little South African involvement in the evolutionary synthesis of the 1930s and 1940s. Evolutionary biology developed into a distinct discipline in South Africa during the 1970s and 1980s when it was dominated by mammalian palaeontology and a vigorous debate around species concepts. In the post-apartheid era, the main focus of evolutionary biology has been the construction of phylogenies for African plants and animals using molecular data, and the use of these phylogenies to answer questions about taxonomic classification and trait evolution. South African biologists have also recently contributed important evidence for some of Darwin’s ideas about plant–animal coevolution, sexual selection, and the role of natural selection in speciation. A bibliographic analysis shows that South African authors produce 2–3% of the world’s publications in the field of evolutionary biology, which is much higher than the value of about 0.5% for publications in all sciences. With its extraordinary biodiversity and well-developed research infrastructure, South Africa is an ideal laboratory from which to advance evolutionary research.

  11. A Cellular MicroRNA Facilitates Regulatory T Lymphocyte Development by Targeting the FOXP3 Promoter TATA-Box Motif.

    Science.gov (United States)

    Zhang, Yiwen; Liu, Weiwei; Chen, Yingshi; Liu, Jun; Wu, Kang; Su, Lishi; Zhang, Wanying; Jiang, Yawen; Zhang, Xu; Zhang, Yijun; Liu, Chao; Tao, Liang; Liu, Bingfeng; Zhang, Hui

    2018-02-01

    The CD4 + CD25 + FOXP3 + regulatory T cells (Tregs) mediate immunological self-tolerance and suppress various immune responses. FOXP3 is a key transcriptional factor for the generation and development of Tregs. Its expression is regulated by various cytokines including TGF-β, IL-2, and IL-10. It is important to further identify the regulatory factors for Tregs. Given that many microRNAs (miRNAs) could specifically interact with the core promoter region and specifically enhance the transcription of many target genes, we searched for any possible miRNA(s) targeting the core promoter region of the FOXP3 gene. We found that miR-4281, an miRNA specifically expressed in hominids, can potently and specifically upregulate FOXP3 expression by directly interacting with the TATA-box motif in the human FOXP3 promoter. Consequently, miR-4281 significantly accelerated the differentiation of human naive cells to induced Tregs (iTregs) that possess immune suppressor functions and weaken the development of graft-versus-host disease in a humanized mouse model. Interestingly, iTregs induced by the combination of TGF-β, IL-2, and chemically synthesized miR-4281 were more stable and functional than those induced by TGF-β and IL-2 alone. Moreover, we found that the IL-2/STAT5 signal transduction upregulates FOXP3 expression not only through the classical pathway, but also by enhancing the expression of the miR-4281 precursor gene ( SNCB ) and, correspondingly, miR-4281. This study reveals a novel mechanism regulating FOXP3 expression and human iTreg development and, therefore, offers a new therapeutic target to manipulate immunosuppressive system. Copyright © 2018 by The American Association of Immunologists, Inc.

  12. Estudios pioneros en torno al origen del lenguaje natural

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    Martínez Contreras, Jorge

    2011-02-01

    Full Text Available It has being an ancient desire to ask apes what their natural lives are. De la Mettrie was the first to propose, in the 18th C., that the sign language of deaf adults could be used with them since they do not speak. We enhance here some of the pioneering projects of the two strategies for this endeavor: the use of ASL and the utilization of lexigrams and computers. Besides the ancient communicative quest with them, the evolutionist’s perspective has seen in these studies a way to find out how the natural language (NL emerged in hominids. If it is clear that apes do no possess totally the NL, the linguistic turn in primatology has left way, as in philosophy, to more complex field and laboratory cognitive studies of less anthropocentric nature.

    Tratar de hablar con los simios y preguntarles cosas sobre su vida natural es un viejo deseo. De la Mettrie propone, en el s. XVIII, que se les enseñe el lenguaje de los sordos en vista de que no pueden hablar. Resaltamos aquí algunos estudios pioneros en relación con las dos estrategias llevadas a cabo para tratar de hablar con los simios: el uso del lenguaje americano de sordos (ASL y el de los lexigramas y computadoras. Además del viejo interés interrogativo humano hacia ellos, la perspectiva evolucionista ha visto en estos estudios un medio de investigar cómo surgió el lenguaje natural (LN en homínidos. Si queda claro que los simios no poseen totalmente el LN, el giro lingüistico en primatología ha cedido, como en filosofía, el paso a estudios cognitivos más complejos, de campo y de laboratorio, de orientación menos antropomórfica.

  13. Structural determinants of a conserved enantiomer-selective carvone binding pocket in the human odorant receptor OR1A1.

    Science.gov (United States)

    Geithe, Christiane; Protze, Jonas; Kreuchwig, Franziska; Krause, Gerd; Krautwurst, Dietmar

    2017-11-01

    Chirality is a common phenomenon within odorants. Most pairs of enantiomers show only moderate differences in odor quality. One example for enantiomers that are easily discriminated by their odor quality is the carvones: humans significantly distinguish between the spearmint-like (R)-(-)-carvone and caraway-like (S)-(+)-carvone enantiomers. Moreover, for the (R)-(-)-carvone, an anosmia is observed in about 8% of the population, suggesting enantioselective odorant receptors (ORs). With only about 15% de-orphaned human ORs, the lack of OR crystal structures, and few comprehensive studies combining in silico and experimental approaches to elucidate structure-function relations of ORs, knowledge on cognate odorant/OR interactions is still sparse. An adjusted homology modeling approach considering OR-specific proline-caused conformations, odorant docking studies, single-nucleotide polymorphism (SNP) analysis, site-directed mutagenesis, and subsequent functional studies with recombinant ORs in a cell-based, real-time luminescence assay revealed 11 amino acid positions to constitute an enantioselective binding pocket necessary for a carvone function in human OR1A1 and murine Olfr43, respectively. Here, we identified enantioselective molecular determinants in both ORs that discriminate between minty and caraway odor. Comparison with orthologs from 36 mammalian species demonstrated a hominid-specific carvone binding pocket with about 100% conservation. Moreover, we identified loss-of-function SNPs associated with the carvone binding pocket of OR1A1. Given carvone enantiomer-specific receptor activation patterns including OR1A1, our data suggest OR1A1 as a candidate receptor for constituting a carvone enantioselective phenotype, which may help to explain mechanisms underlying a (R)-(-)-carvone-specific anosmia in humans.

  14. Insights into the Toba Super-Eruption using SEM Analysis of Ash Deposits

    Science.gov (United States)

    Gatti, E.; Achyuthan, H.; Durant, A. J.; Gibbard, P.; Mokhtar, S.; Oppenheimer, C.; Raj, R.; Shridar, A.

    2010-12-01

    The ~74 ka Youngest Toba Tuff (YTT) super-eruption of Toba volcano, Northern Sumatra, was the largest eruption of the Quaternary (magnitude M= 8.8) and injected massive quantities of volcanic gases and ash into the stratosphere. YTT deposits covered at least 40,000,000 km2 of Southeast Asia and are preserved in river valleys across peninsular India and Malaysia, and in deep-sea tephra layers in the Indian Ocean, Bay of Bengal and South China Sea. Initial studies hypothesized the eruption caused immediate and substantial global cooling during the ~ 1 kyr between Dansgaard-Oeschger events 19 and 20 which devastated ecosystems and hominid populations. A more recent review argues against severe post-YTT climatic deterioration and cannot find clear evidence for considerable impacts on ecosystems or bio-diversity. The determination of the eruptive parameters is crucial in this issue to document the eruption and understand the potential impacts from future super-volcanic eruptions. Volcanic ash deposits can offer dramatic insights into key eruptive parameters, including magnitude, duration and plume height. The composition and shape of volcanic ashes can be used to interpret physical properties of an erupting magma and tephra transport, while textural characteristics such as grain roughness and surface vescicularity can provide insights into degassing history, volatile content and explosive activity of the volcano. We present a stratigraphic and sedimentological analysis of YTT deposits in stratified contexts at three localities in India, at two sites in Peninsular Malaysia, and at several localities around Lake Toba and on Samosir Island, Sumatra. These sites offer excellent constraints on the spatial distribution of YTT deposits which can be used to infer dispersal directions of the cloud, and provide insights into environmental controls on preservation of tephra beds. The research aims at a systematic interpretation of the Toba tephra to understand the volcanic

  15. Human-Specific Histone Methylation Signatures at Transcription Start Sites in Prefrontal Neurons

    Science.gov (United States)

    Cheung, Iris; Bharadwaj, Rahul; Chou, Hsin-Jung; Houston, Isaac B.; Peter, Cyril J.; Mitchell, Amanda C.; Yao, Wei-Dong; Myers, Richard H.; Chen, Jiang-fan; Preuss, Todd M.; Rogaev, Evgeny I.; Jensen, Jeffrey D.; Weng, Zhiping; Akbarian, Schahram

    2012-01-01

    Cognitive abilities and disorders unique to humans are thought to result from adaptively driven changes in brain transcriptomes, but little is known about the role of cis-regulatory changes affecting transcription start sites (TSS). Here, we mapped in human, chimpanzee, and macaque prefrontal cortex the genome-wide distribution of histone H3 trimethylated at lysine 4 (H3K4me3), an epigenetic mark sharply regulated at TSS, and identified 471 sequences with human-specific enrichment or depletion. Among these were 33 loci selectively methylated in neuronal but not non-neuronal chromatin from children and adults, including TSS at DPP10 (2q14.1), CNTN4 and CHL1 (3p26.3), and other neuropsychiatric susceptibility genes. Regulatory sequences at DPP10 and additional loci carried a strong footprint of hominid adaptation, including elevated nucleotide substitution rates and regulatory motifs absent in other primates (including archaic hominins), with evidence for selective pressures during more recent evolution and adaptive fixations in modern populations. Chromosome conformation capture at two neurodevelopmental disease loci, 2q14.1 and 16p11.2, revealed higher order chromatin structures resulting in physical contact of multiple human-specific H3K4me3 peaks spaced 0.5–1 Mb apart, in conjunction with a novel cis-bound antisense RNA linked to Polycomb repressor proteins and downregulated DPP10 expression. Therefore, coordinated epigenetic regulation via newly derived TSS chromatin could play an important role in the emergence of human-specific gene expression networks in brain that contribute to cognitive functions and neurological disease susceptibility in modern day humans. PMID:23185133

  16. Les hominoïdes fossiles : une aide pour l’éducation en Afrique Fossil hominoids: an educational help in Africa

    Directory of Open Access Journals (Sweden)

    Brigitte Senut

    2009-10-01

    Full Text Available L’Afrique est un continent privilégié pour décrypter notre histoire partagée avec celle des grands singes et comprendre l’émergence de notre famille en rapport avec l’environnement. Aujourd’hui de nombreuses expéditions  internationales mènent des recherches sur le continent et plus spécialement dans les pays d’Afrique orientale. Le riche patrimoine fossile découvert dans des endroits souvent isolés est transféré dans les musées nationaux, (créés le plus souvent par des expatriés et situés dans les capitales où l’accès y est plus facile pour les chercheurs internationaux, mais souvent difficile voire impossible pour les gens qui habitent près des sites fossilifères. Que se passe-t-il au niveau local ? Le plus souvent, les populations ont été marginalisées, des sentiments de frustration sont apparus, notamment en raison de la grande médiatisation des découvertes de laquelle les locaux sont souvent exclus. Or, ce sont ces populations locales qui sont les gardiennes du patrimoine. Les choses changent progressivement et aujourd’hui, de plus en plus de chercheurs de terrain s’impliquent dans la vie locale et les besoins locaux. Notre engagement de scientifique en tant que citoyen est fondamental : l’éducation est un droit pour tous, comme cela est signalé dans la déclaration universelle des droits de l’homme. Dans le cadre des travaux entrepris en Afrique avec l’équipe, des grands singes et des hominidés fossiles ont été découverts dans trois pays africains sur lesquels cet article est focalisé : l’Ouganda, le Kenya et la Namibie ; ces données montrent que l’évolution des grands singes ne s’est pas déroulée exclusivement en Afrique orientale, mais bien sur l’ensemble du continent, comme cela a été confirmé plus récemment par des découvertes en Afrique centrale et occidentale. Ces découvertes ont été réalisées avec des citoyens de chacun de ces pays et ont donné lieu

  17. El rapto de Europa... una y otra vez

    Directory of Open Access Journals (Sweden)

    Eduardo GARCIA SÁNCHEZ

    2009-12-01

    conocimiento del medio por parte de sus protagonistas. Mientras los ensayos de colonización anteriores no parecen tener éxito, los datos paleoantropológicos y arqueológicos del registro documentado desde circa 550 Ka BP en adelante indican claramente signos de continuidad de este poblamiento, enlazando con las primeras manifestaciones de las tecnologías y los tipos humanos característicos del Paleolítico medio.ABSTRACT: European Early Palaeolithic's record of Europe shows, at least, three human occupation episodes. The oldest one is only recorded in the Iberian Peninsula. The sites are scarce and dated between 1,5 and 1,25 Ma BP. The lithic assemblages are very similar to those recorded in Dmanisi (Georgia circa 1,8 Ma BP and may represent the same hominid dispersal event. This is related to the faunal changes detected in Caucasus, Middle East and European ecosystems by the Plio-Pleistocene conventional limit. This event involved the diffusion of African taxa in those regions. A second human occupation of Europe episode, restricted into the Mediterranean area, it is recorded by a slightly more abundant number of archaeological sites. They are dated between late Early Pleistocene and Matuyama/Brunhes limit, berween OIS 25-OIS 24 and OIS 19-OIS 18 transition. Paleoantropological and archaeological record points to an Asian origin of this hominid dispersal, related with the Galerian faunal event. After a new archaeological record hiatus, there are new evidences of anthropic activity in Europe since OIS 16-OIS 15. At this time the European geographic range populated by hominids increases, reaching as northern latitudes as South Great Britain and North Germany during the warm isotopic stages. In general terms, locations representing this third phase involved the introduction in Europe of new technologies and behavioural trends, as a better knowledge of the environment. While the previous human occupation events don't seem to be successful, paleoanthropological and

  18. Virtual Exploration of Earth's Evolution

    Science.gov (United States)

    Anbar, A. D.; Bruce, G.; Semken, S. C.; Summons, R. E.; Buxner, S.; Horodyskyj, L.; Kotrc, B.; Swann, J.; Klug Boonstra, S. L.; Oliver, C.

    2014-12-01

    Traditional introductory STEM courses often reinforce misconceptions because the large scale of many classes forces a structured, lecture-centric model of teaching that emphasizes delivery of facts rather than exploration, inquiry, and scientific reasoning. This problem is especially acute in teaching about the co-evolution of Earth and life, where classroom learning and textbook teaching are far removed from the immersive and affective aspects of field-based science, and where the challenges of taking large numbers of students into the field make it difficult to expose them to the complex context of the geologic record. We are exploring the potential of digital technologies and online delivery to address this challenge, using immersive and engaging virtual environments that are more like games than like lectures, grounded in active learning, and deliverable at scale via the internet. The goal is to invert the traditional lecture-centric paradigm by placing lectures at the periphery and inquiry-driven, integrative virtual investigations at the center, and to do so at scale. To this end, we are applying a technology platform we devised, supported by NASA and the NSF, that integrates a variety of digital media in a format that we call an immersive virtual field trip (iVFT). In iVFTs, students engage directly with virtual representations of real field sites, with which they interact non-linearly at a variety of scales via game-like exploration while guided by an adaptive tutoring system. This platform has already been used to develop pilot iVFTs useful in teaching anthropology, archeology, ecology, and geoscience. With support the Howard Hughes Medical Institute, we are now developing and evaluating a coherent suite of ~ 12 iVFTs that span the sweep of life's history on Earth, from the 3.8 Ga metasediments of West Greenland to ancient hominid sites in East Africa. These iVFTs will teach fundamental principles of geology and practices of scientific inquiry, and expose

  19. Variation among early Homo crania from Olduvai Gorge and the Koobi Fora region.

    Science.gov (United States)

    Rightmire, G P

    1993-01-01

    Fossils recognized as early Homo were discovered first at Olduvai Gorge in 1959 and 1960. Teeth, skull parts and hand bones representing three individuals were found in Bed I, and more material followed from Bed I and lower Bed II. By 1964, L.S.B. Leakey, P.V. Tobias, and J.R. Napier were ready to name Homo habilis. But almost as soon as they had, there was confusion over the hypodigm of the new species. Tobias himself suggested that OH 13 resembles Homo erectus from Java, and he noted that OH 16 has teeth as large as those of Australopithecus. By the early 1970s, however, Tobias had put these thoughts behind him and returned to the opinion that all of the Olduvai remains are Homo habilis. At about this time, important discoveries began to flow from the Koobi Fora region in Kenya. To most observers, crania such as KNM-ER 1470 confirmed the presence of Homo in East Africa at an early date. Some of the other specimens were problematical. A.C. Walker and R.E. Leakey raised the possibility that larger skulls including KNM-ER 1470 differ significantly from smaller-brained, small-toothed individuals such as KNM-ER 1813. Other workers emphasized that there are differences of shape as well as size among the hominids from Koobi Fora. There is now substantial support for the view that in the Turkana and perhaps also in the Olduvai assemblages, there is more variation than would be expected among male and female conspecifics. One way to approach this question of sorting would be to compare all of the new fossils against the original material from Olduvai which was used to characterize Homo habilis in 1964. A problem is that the Olduvai remains are fragmentary, and none of them provides much information about vault form or facial structure. An alternative is to work first with the better crania, even if these are from other sites. I have elected to treat KNM-ER 1470 and KNM-ER 1813 as key individuals. Comparisons are based on discrete anatomy and measurements. Metric results

  20. Delineation of separate brain regions used for scientific versus engineering modes of thinking

    Science.gov (United States)

    Patterson, Clair C.

    1994-08-01

    Powerful, latent abilities for extreme sophistication in abstract rationalization as potential biological adaptive behavioral responses were installed entirely through accident and inadvertence by biological evolution in the Homo sapiens sapiens species of brain. These potentials were never used, either in precursor species as factors in evolutionary increase in hominid brain mass, nor in less sophisticated forms within social environments characterized by Hss tribal brain population densities. Those latent abilities for unnatural biological adaptive behavior were forced to become manifest in various ways by growths in sophistication of communication interactions engendered by large growths in brain population densities brought on by developments in agriculture at the onset of the Holocene. It is proposed that differences probably exist between regions of the Hss brain involved in utilitarian, engineering types of problem conceptualization-solving versus regions of the brain involved in nonutilitarian, artistic-scientific types of problem conceptualization-solving. Populations isolated on separate continents from diffusive contact and influence on cultural developments, and selected for comparison of developments during equivalent stages of technological and social sophistication in matching 4000 year periods, show, at the ends of those periods, marked differences in aesthetic attributes expressed in cosmogonies, music, and writing (nonutilitarian thinking related to science and art). On the other hand the two cultures show virtually identical developments in three major stages of metallurgical technologies (utilitarian thinking related to engineering). Such archaeological data suggest that utilitarian modes of thought may utilize combinations of neuronal circuits in brain regions that are conserved among tribal populations territorially separated from each other for tens of thousands of years. Such conservation may not be true for neuronal circuits involved in

  1. The Environmental Settings of Homo-Sapience Dispersal and the Neolithic Revolution in the Dead Sea - Red Sea Rift Valley

    Science.gov (United States)

    Stein, M.

    2014-12-01

    The Dead Sea-Red Sea Rift accommodated climatic and historic events that have fundamentally influenced the evolution of hominids. Among these developments, the Homo-Sapience (HS) dispersal "out of Africa" and the "Neolithic Revolution (NR)" represent major benchmarks. These developments occurred during the last interglacial and the post-glacial periods when the Red Sea - Levant region was overall arid. Nevertheless, wetter intervals prevailed within these arid periods, allowed the human culture development. The information on these wetter periods is stored in the sedimentary archives that were formed in the Rift. Lake Lisan that expanded all over the Dead Sea- Jordan- Kinnarot basin during the last glacial period retreated and contracted when the ice receded at the northern latitudes. At ~ 14-13 ka BP the lake dropped abruptly and deposited thick sequences of halite. Subsequently, terra rossa soil was re-mobilized from the Judea Mountains and accumulated along the Jordan Valley comprising the Fazael Fm. This soil and the availability of water in the Jordan Valley allow the establishment of the early agriculture settlements of Jericho, Gilgal and Fazael (at ~10-9 ka BP, the "peak" of sapropel S1, when enhance flow of Nile waters arrived to the Mediterranean). During the last interglacial HS dispersal occurs along the Red Sea- Jordan Valley corridor. Evidence for periods of wetness in this rather hyperarid region comes from fringing coral reefs along the Red Sea- Gulf of Aqaba shores, speleothems and travertines in the southern Negev desert -Arava valley and from lake sediments that were recently drilled at the deepest floor of the Dead Sea. All inventories indicate interval of enhanced wetness at ~ 128-122 ka BP, when sapropel S5 occurred. Thus, it appears that the periods of sapropels S1 and S5 were favorite for human culture development along the Red Sea - Jordan rift valley. Nevertheless, these human-development periods terminated abruptly at ~118-116 ka BP and

  2. On the nature and evolution of the neural bases of human language

    Science.gov (United States)

    Lieberman, Philip

    2002-01-01

    the brains of human beings and other species provides insight into the evolution of the brain bases of human language. The neural substrate that regulated motor control in the common ancestor of apes and humans most likely was modified to enhance cognitive and linguistic ability. Speech communication played a central role in this process. However, the process that ultimately resulted in the human brain may have started when our earliest hominid ancestors began to walk.

  3. New dates reignite human evolution debate

    International Nuclear Information System (INIS)

    Nolch, G.

    2000-01-01

    Australian research into the Asian fossil record is unearthing controversial evidence with implications for the evolution of humans. Dr Jian-xin Zhao and Prof Ken Collerson from the University of Queensland's Department of Earth Sciences have been studying the fossil record in East Asia for clues to the early migration of hominids out of Africa in collaboration with Chinese archaeologists Dr Kai Hu of Nanjing University and Hankui Xu of Nanjing Institute of Palaeontology, Academia Sinica. Together they have been studying the remains of Nanjing Man, the name given to two Homo erectus skulls and the tooth of a third individual discovered in Tangshan Cave 250 km north-west of Shanghai. Dr Zhao and Prof Collerson have now employed more accurate dating techniques and materials, using a mass spectrometer to analyse the amounts of thorium-230 and uranium-234 in a calcite flowstone above the Nanjing Man fossil bed. Unlike fossil teeth, uranium and thorium became locked into the flowstone's crystal lattice when the calcite became crystallised. Because of this, the U-series decay in the calcite reliably records when the calcite crystallised. Taking into account the half-lives of uranium-234 and thorium-230, Dr Zhao and Prof Collerson determined the age of the calcite flowstone to be 577,000 years old (+44,000/-34,000 years). As the flowstone overlies the fossil bed, this date only defines the minimum age of the Nanjing Man fossil bed. For comparison, the dentine and enamel components of one fossil deer tooth collected from the Nanjing Man fossil bed yielded discordant mass spectrometric U-series ages of 388,000 and 130,100 years, respectively. Dr Zhao says that this 'strongly demonstrates the unreliability of fossil teeth as a chronometer'. Other evidence in the sediments surrounding the fossils has been the presence of flora and fauna that are typical of a glacial period. Dr Zhao therefore believes that the skulls could have been deposited during a glacial period

  4. Parallel evolution of Streptococcus pneumoniae and Streptococcus mitis to pathogenic and mutualistic lifestyles.

    Science.gov (United States)

    Kilian, Mogens; Riley, David R; Jensen, Anders; Brüggemann, Holger; Tettelin, Hervé

    2014-07-22

    The bacterium Streptococcus pneumoniae is one of the leading causes of fatal infections affecting humans. Intriguingly, phylogenetic analysis shows that the species constitutes one evolutionary lineage in a cluster of the otherwise commensal Streptococcus mitis strains, with which humans live in harmony. In a comparative analysis of 35 genomes, including phylogenetic analyses of all predicted genes, we have shown that the pathogenic pneumococcus has evolved into a master of genomic flexibility while lineages that evolved into the nonpathogenic S. mitis secured harmonious coexistence with their host by stabilizing an approximately 15%-reduced genome devoid of many virulence genes. Our data further provide evidence that interspecies gene transfer between S. pneumoniae and S. mitis occurs in a unidirectional manner, i.e., from S. mitis to S. pneumoniae. Import of genes from S. mitis and other mitis, anginosus, and salivarius group streptococci ensured allelic replacements and antigenic diversification and has been driving the evolution of the remarkable structural diversity of capsular polysaccharides of S. pneumoniae. Our study explains how the unique structural diversity of the pneumococcal capsule emerged and conceivably will continue to increase and reveals a striking example of the fragile border between the commensal and pathogenic lifestyles. While genomic plasticity enabling quick adaptation to environmental stress is a necessity for the pathogenic streptococci, the commensal lifestyle benefits from stability. Importance: One of the leading causes of fatal infections affecting humans, Streptococcus pneumoniae, and the commensal Streptococcus mitis are closely related obligate symbionts associated with hominids. Faced with a shortage of accessible hosts, the two opposing lifestyles evolved in parallel. We have shown that the nonpathogenic S. mitis secured harmonious coexistence with its host by stabilizing a reduced genome devoid of many virulence genes

  5. Greening of the Sahara - a paleo perspective on the history of water in the Middle East and North Africa

    Science.gov (United States)

    Bar-Matthews, M.

    2012-04-01

    The Middle-East, mostly at its southern edge together with North Africa, the northern edge of the Sahara Desert, are located at the boundary between high- to-mid latitude and tropical-subtropical climate systems. The geographical duality of desert adjacent to Mediterranean-type climate regions played and still plays a major role on the water availability. Thanks to the number of important paleoclimate studies that been made on accurate dating of cave speleothems in Southern Arabia and Oman (Fleitmann et al., 2011) and in the northeast Sahara, the Negev Desert Israel (Vaks et al., 2010) and the study of sapropels in Eastern and central Mediterranean (Almogi-Labin et al., 2009; Osborne et al, 2008), it is clear that the region was graced with water during peak interglacials when the African monsoon and westerly storm/rainfall systems intensified. Northward penetration of the Inter Tropical Convergence Zone over the Arabian and African continents resulted in increased discharge of the Nile River and rivers that emerged from central Sahara into the Eastern Mediterranean Sea. Correspondingly, enhanced westerly wind activity led to an increase in rainfall from Atlantic-Mediterranean sources over the entire Mediterranean basin, which even penetrated south into the north-east corner of the Sahara Desert. The Saharo-Arabian Desert became narrower and climatic "windows" opened for the dispersal of hominids and animals out of the African continent at 250-239, 210-193, 138-120, 108-98, 87-84 and 10-6.5 ka BP, with severe dry conditions in between. Greening of the Sahara Desert at these intervals is supported also by various marine and terrestrial records, such as corals, lakes, tufa deposits and archeological findings. Dry conditions prevailed in the Sahara desert during glacials. This is in contrast to the climatic conditions in the Eastern Mediterranean coastal region and the Jordan Rift Valley (Bar-Matthews et al., 2003; Lisker et al., 2010), where water was available for

  6. The Carbon Crisis: An Evolutionary Perspective

    Science.gov (United States)

    Peacock, K.

    2013-12-01

    By the 'carbon crisis' I mean the coupled crises of the depletion of the highest-EROI sources of fossil fuels and the global warming caused by our use of those fossil fuels. (EROI means 'energy return on energy investment'; Hall 2011.) While global warming is arguably more urgent, either of these factors would sooner or later be sufficient by itself to call a halt to our global-scale, energy-intensive, high technology economy. In lethal combination, they threaten to drastically reduce the capacity of the planet to support 7+ billion talking hominids. I will pull the camera back for a very long view and characterize the carbon crisis and our possible responses to it from an evolutionary and ecological perspective. It remains unclear why sapiens emerged rather suddenly as the most successful member of the family Homo about 50 to 60 kya; some argue that this neurological explosion could be due to our ancestors having survived the rigors of the Toba population bottleneck, which presumably would have favoured high adaptability (Ambrose 1998). Whatever the cause, Paleolithic humans deployed an unprecedented combination of technological and social ingenuity (the capacity for adaptive social organization; Homer-Dixon 2001). Aided by the relatively benign climate of the Holocene and ultimately by our increasing ability to tap into the resources of the 'found' ecology, especially the vast stores of hydrocarbons bequeathed by the Paleozoic and Mesozoic eras, our population has grown exponentially to its present unsteady pinnacle of (possibly) temporary reproductive success. The question now is what happens next. It was human ingenuity that got us through the ice age, put footprints on the Moon, and brought us to this crisis point; now, only human ingenuity (both social and technical) can get us past it. Our species will finally achieve a sustainable mode of existence on this planet when (in E. Odum's words; 1973) 'the present-day concept of ';unlimited exploitation of

  7. Muscle-specific integrins in masseter muscle fibers of chimpanzees: an immunohistochemical study.

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    Gianluigi Vaccarino

    2010-05-01

    Full Text Available Most notably, recent comparative genomic analyses strongly indicate that the marked differences between modern human and chimpanzees are likely due more to changes in gene regulation than to modifications of the genes. The most peculiar aspect of hominoid karyotypes is that human have 46 chromosomes whereas gorillas and chimpanzees have 48. Interestingly, human and chimpanzees do share identical inversions on chromosome 7 and 9 that are not evident in the gorilla karyotype. Thus, the general phylogeny suggests that humans and chimpanzees are sister taxa; based on this, it seems that human-chimpanzee sequence similarity is an astonishing 99%. At this purpose, of particular interest is the inactivation of the myosin heavy chain 16 (MYH16 gene, most prominently expressed in the masticatory muscle of mammals. It has been showed that the loss of this gene in humans may have resulted in smaller masticatory muscle and consequential changes to cranio-facial morphology and expansion of the human brain case. Powerful masticatory muscles are found in most primates; contrarily, in both modern and fossil member Homo, these muscles are considerably smaller. The evolving hominid masticatory apparatus shifted towards a pattern of gracilization nearly simultaneously with accelerated encephalization in early Homo. To better comprehend the real role of the MYH16 gene, we studied the primary proteins present in the muscle fibers of humans and non-humans, in order to understand if they really can be influenced by MYH16 gene. At this aim we examined the muscle-specific integrins, alpha 7B and beta 1D-integrins, and their relative fetal isoforms, alpha 7A and beta 1A-integrins, analyzing, by immunohistochemistry, muscle biopsies of two components of a chimpanzee's group in captivity, an alpha male and a non-alpha male subjects; all these integrins participate in vital biological processes such as maintenance of tissue integrity, embryonic development, cell

  8. Chromosomal evolution of the PKD1 gene family in primates

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    Krawczak Michael

    2008-09-01

    Full Text Available Abstract Background The autosomal dominant polycystic kidney disease (ADPKD is mostly caused by mutations in the PKD1 (polycystic kidney disease 1 gene located in 16p13.3. Moreover, there are six pseudogenes of PKD1 that are located proximal to the master gene in 16p13.1. In contrast, no pseudogene could be detected in the mouse genome, only a single copy gene on chromosome 17. The question arises how the human situation originated phylogenetically. To address this question we applied comparative FISH-mapping of a human PKD1-containing genomic BAC clone and a PKD1-cDNA clone to chromosomes of a variety of primate species and the dog as a non-primate outgroup species. Results Comparative FISH with the PKD1-cDNA clone clearly shows that in all primate species studied distinct single signals map in subtelomeric chromosomal positions orthologous to the short arm of human chromosome 16 harbouring the master PKD1 gene. Only in human and African great apes, but not in orangutan, FISH with both BAC and cDNA clones reveals additional signal clusters located proximal of and clearly separated from the PKD1 master genes indicating the chromosomal position of PKD1 pseudogenes in 16p of these species, respectively. Indeed, this is in accordance with sequencing data in human, chimpanzee and orangutan. Apart from the master PKD1 gene, six pseudogenes are identified in both, human and chimpanzee, while only a single-copy gene is present in the whole-genome sequence of orangutan. The phylogenetic reconstruction of the PKD1-tree reveals that all human pseudogenes are closely related to the human PKD1 gene, and all chimpanzee pseudogenes are closely related to the chimpanzee PKD1 gene. However, our statistical analyses provide strong indication that gene conversion events may have occurred within the PKD1 family members of human and chimpanzee, respectively. Conclusion PKD1 must have undergone amplification very recently in hominid evolution. Duplicative

  9. The first hominin from the early Pleistocene paleocave of Haasgat, South Africa

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    AB Leece

    2016-05-01

    Full Text Available Haasgat is a primate-rich fossil locality in the northeastern part of the Fossil Hominid Sites of South Africa UNESCO World Heritage Site. Here we report the first hominin identified from Haasgat, a partial maxillary molar (HGT 500, that was recovered from an ex situ calcified sediment block sampled from the locality. The in situ fossil bearing deposits of the Haasgat paleokarstic deposits are estimated to date to slightly older than 1.95 Ma based on magnetobiostratigraphy. This places the hominin specimen at a critical time period in South Africa that marks the last occurrence of Australopithecus around 1.98 Ma and the first evidence of Paranthropus and Homo in the region between ∼2.0 and 1.8 Ma. A comprehensive morphological evaluation of the Haasgat hominin molar was conducted against the current South African catalogue of hominin dental remains and imaging analyses using micro-CT, electron and confocal microscopy. The preserved occlusal morphology is most similar to Australopithecus africanus or early Homo specimens but different from Paranthropus. Occlusal linear enamel thickness measured from micro-CT scans provides an average of ∼2.0 mm consistent with Australopithecus and early Homo. Analysis of the enamel microstructure suggests an estimated periodicity of 7–9 days. Hunter–Schreger bands appear long and straight as in some Paranthropus, but contrast with this genus in the short shape of the striae of Retzius. Taken together, these data suggests that the maxillary fragment recovered from Haasgat best fits within the Australopithecus—early Homo hypodigms to the exclusion of the genus Paranthropus. At ∼1.95 Ma this specimen would either represent another example of late occurring Australopithecus or one of the earliest examples of Homo in the region. While the identification of this first hominin specimen from Haasgat is not unexpected given the composition of other South African penecontemporaneous site deposits, it represents

  10. Macromammalian faunas, biochronology and palaeoecology of the early Pleistocene Main Quarry hominin-bearing deposits of the Drimolen Palaeocave System, South Africa.

    Science.gov (United States)

    Adams, Justin W; Rovinsky, Douglass S; Herries, Andy I R; Menter, Colin G

    2016-01-01

    The Drimolen Palaeocave System Main Quarry deposits (DMQ) are some of the most prolific hominin and primate-bearing deposits in the Fossil Hominids of South Africa UNESCO World Heritage Site. Discovered in the 1990s, excavations into the DMQ have yielded a demographically diverse sample of Paranthropus robustus (including DNH 7, the most complete cranium of the species recovered to date), early Homo, Papio hamadryas robinsoni and Cercopithecoides williamsi. Alongside the hominin and primate sample is a diverse macromammalian assemblage, but prior publications have only provided a provisional species list and an analysis of the carnivores recovered prior to 2008. Here we present the first description and analysis of the non-primate macromammalian faunas from the DMQ, including all 826 taxonomically identifiable specimens catalogued from over two decades of excavation. We also provide a biochronological interpretation of the DMQ deposits and an initial discussion of local palaeoecology based on taxon representation.The current DMQ assemblage consists of the remains of minimally 147 individuals from 9 Orders and 14 Families of mammals. The carnivore assemblage described here is even more diverse than established in prior publications, including the identification of Megantereon whitei, Lycyaenops silberbergi, and first evidence for the occurrence of Dinofelis cf. barlowi and Dinofelis aff. piveteaui within a single South African site deposit. The cetartiodactyl assemblage is dominated by bovids, with the specimen composition unique in the high recovery of horn cores and dominance of Antidorcas recki remains. Other cetartiodactyl and perissodactyl taxa are represented by few specimens, as are Hystrix and Procavia; the latter somewhat surprisingly so given their common occurrence at penecontemporaneous deposits in the region. Equally unusual (particularly given the size of the sample) is the identification of single specimens of giraffoid, elephantid and aardvark

  11. The first hominin from the early Pleistocene paleocave of Haasgat, South Africa.

    Science.gov (United States)

    Leece, A B; Kegley, Anthony D T; Lacruz, Rodrigo S; Herries, Andy I R; Hemingway, Jason; Kgasi, Lazarus; Potze, Stephany; Adams, Justin W

    2016-01-01

    Haasgat is a primate-rich fossil locality in the northeastern part of the Fossil Hominid Sites of South Africa UNESCO World Heritage Site. Here we report the first hominin identified from Haasgat, a partial maxillary molar (HGT 500), that was recovered from an ex situ calcified sediment block sampled from the locality. The in situ fossil bearing deposits of the Haasgat paleokarstic deposits are estimated to date to slightly older than 1.95 Ma based on magnetobiostratigraphy. This places the hominin specimen at a critical time period in South Africa that marks the last occurrence of Australopithecus around 1.98 Ma and the first evidence of Paranthropus and Homo in the region between ∼2.0 and 1.8 Ma. A comprehensive morphological evaluation of the Haasgat hominin molar was conducted against the current South African catalogue of hominin dental remains and imaging analyses using micro-CT, electron and confocal microscopy. The preserved occlusal morphology is most similar to Australopithecus africanus or early Homo specimens but different from Paranthropus. Occlusal linear enamel thickness measured from micro-CT scans provides an average of ∼2.0 mm consistent with Australopithecus and early Homo. Analysis of the enamel microstructure suggests an estimated periodicity of 7-9 days. Hunter-Schreger bands appear long and straight as in some Paranthropus, but contrast with this genus in the short shape of the striae of Retzius. Taken together, these data suggests that the maxillary fragment recovered from Haasgat best fits within the Australopithecus-early Homo hypodigms to the exclusion of the genus Paranthropus. At ∼1.95 Ma this specimen would either represent another example of late occurring Australopithecus or one of the earliest examples of Homo in the region. While the identification of this first hominin specimen from Haasgat is not unexpected given the composition of other South African penecontemporaneous site deposits, it represents one of the few hominin

  12. Macromammalian faunas, biochronology and palaeoecology of the early Pleistocene Main Quarry hominin-bearing deposits of the Drimolen Palaeocave System, South Africa

    Directory of Open Access Journals (Sweden)

    Justin W. Adams

    2016-04-01

    Full Text Available The Drimolen Palaeocave System Main Quarry deposits (DMQ are some of the most prolific hominin and primate-bearing deposits in the Fossil Hominids of South Africa UNESCO World Heritage Site. Discovered in the 1990s, excavations into the DMQ have yielded a demographically diverse sample of Paranthropus robustus (including DNH 7, the most complete cranium of the species recovered to date, early Homo, Papio hamadryas robinsoni and Cercopithecoides williamsi. Alongside the hominin and primate sample is a diverse macromammalian assemblage, but prior publications have only provided a provisional species list and an analysis of the carnivores recovered prior to 2008. Here we present the first description and analysis of the non-primate macromammalian faunas from the DMQ, including all 826 taxonomically identifiable specimens catalogued from over two decades of excavation. We also provide a biochronological interpretation of the DMQ deposits and an initial discussion of local palaeoecology based on taxon representation.The current DMQ assemblage consists of the remains of minimally 147 individuals from 9 Orders and 14 Families of mammals. The carnivore assemblage described here is even more diverse than established in prior publications, including the identification of Megantereon whitei, Lycyaenops silberbergi, and first evidence for the occurrence of Dinofelis cf. barlowi and Dinofelis aff. piveteaui within a single South African site deposit. The cetartiodactyl assemblage is dominated by bovids, with the specimen composition unique in the high recovery of horn cores and dominance of Antidorcas recki remains. Other cetartiodactyl and perissodactyl taxa are represented by few specimens, as are Hystrix and Procavia; the latter somewhat surprisingly so given their common occurrence at penecontemporaneous deposits in the region. Equally unusual (particularly given the size of the sample is the identification of single specimens of giraffoid, elephantid

  13. Organization of the lithic production and use-wear analysis from Middle Paleolithic site of Abric Romaní. Level Ja (Capellades, Barcelona, Spain

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    Martínez, Kenneth

    2001-06-01

    Full Text Available The fieldwork from layer Ja at Abric Romaní provides some interesting insights on the examination of patterns of late premodern hominid behavior The reconstruction of châine opératoire and use-wear analysis point out planning in the consumption of raw materials and in the design of stone tools for specific tasks. The archaeological record shows complexity in the settlement system and intrasite context, likewise, the land use depends mainly on the curation of tools through transport of cores, like reserve of tools, and retouched tools. The flakes were versatile tools; working wood, hide and participating in butchering activities and denticulates were used mainly on wood, probably to make points. So far, this work seeks to understand Middle Paleolithic way of life in its own right without comparing it with a hypothetical model of modern behavior.

    La intervención arqueológica del nivel Ja del Abric Romaní ha aportado una información muy valiosa para comprender los patrones conductuales de los últimos homínidos arcaicos. La reconstrucción de la organización de la producción lítica y los análisis funcionales indican una planificación a la hora de gestionar la materia prima y en el diseño de los útiles según tareas específicas. El registro arqueológico muestra una estructuración compleja de las ocupaciones en el interior del abrigo, así como una organización a escala regional de las ocupaciones. La explotación del entorno dependía principalmente de una gestión cuidada de la materia prima mediante el desplazamiento por el territorio de núcleos, como reserva de útiles, y de objetos retocados. Las lascas fueron útiles versátiles, trabajaron tanto madera como piel, y también participaron en actividades de carnicería. Por su parte, los denticulados fueron utilizados para trabajar madera, probablemente para elaborar puntas en este material. Por tanto, el presente artículo intenta comprender el modo de vida de

  14. Evolution of human IgH3'EC duplicated structures: both enhancers HS1,2 are polymorphic with variation of transcription factor's consensus sites.

    Science.gov (United States)

    Giambra, Vincenzo; Fruscalzo, Alberto; Giufre', Maria; Martinez-Labarga, Cristina; Favaro, Marco; Rocchi, Mariano; Frezza, Domenico

    2005-02-14

    the 17-bp external element in hominids. The relevance of the polymorphisms in the HS1,2 enhancers is due to the variable number of binding sites for the transcription factors: NF-kappaB, CMYB, BSAP1/2, AP1/4, E47, MyoD and muE5 and thus to the possible influence of these variations on switch, production of Ig and on maturation of B cells.

  15. Fossilization Type of Elephas hysudrindicus from Blora on the Basis of Petrographic and Scanning Electron Microscopic Analyses

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    Danny Z. Herman

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v6i2.117Either fossils of the hominid or vertebrate have long been known from terraces along the Solo River in Central and East Java. Most terraces consist of andesitic sand to andesitic tuffaceous sand with either gravelpebble or conglomerate and some of them contain vertebrate fossils. It is in this place, an ancient elephant fossil named Elephas hysudrindicus was discovered in 2009. This fossil was discovered at an abandoned sand quarry of Sunggun area, Medalem Village, Kradenan Subregency, Blora Regency which and can be mentioned as a great event for the Geological Museum. It was said as a phenomenal discovery, because the fossil was found within the terrace with condition of nearly complete skeleton of an individual elephant. Some bone fragments of Elephas hysudrindicus fossil is treated as rock specimens because a number of minerals fill in either pore spaces or cavities or cracks within bones, and such infilling minerals can be observed in cut sections of the bones. Main goals of the study are to determine the distribution and type of minerals within the bones, interpret environment of deposition, and identify fossilization type. The methodology used in this study consists of petrographic and Scanning Electron Microscopic (SEM analyses. Based on the petrographical observation, some bone specimens of Elephas hysudrindicus fossil are characterized by fibrous and porous feature with cracks occuring locally. Whilst, examination with SEM shows that the bone specimens are apparently composed of collophane or massive cryptocrystalline variety of apatite as the principal component of fossil bone, having physical characteristic of spheroidal structure and cavities of 100 to 1500 micron (μ in diameter. Most cavities and pore spaces are predominantly filled in by either authigenic crystals of rhombohedral calcite and lesser pseudohexagonal kaolinite with either slightly minerals of manganese oxide or iron oxide or ilmenite

  16. Key cognitive preconditions for the evolution of language.

    Science.gov (United States)

    Donald, Merlin

    2017-02-01

    Languages are socially constructed systems of expression, generated interactively in social networks, which can be assimilated by the individual brain as it develops. Languages co-evolved with culture, reflecting the changing complexity of human culture as it acquired the properties of a distributed cognitive system. Two key preconditions set the stage for the evolution of such cultures: a very general ability to rehearse and refine skills (evident early in hominin evolution in toolmaking), and the emergence of material culture as an external (to the brain) memory record that could retain and accumulate knowledge across generations. The ability to practice and rehearse skill provided immediate survival-related benefits in that it expanded the physical powers of early hominins, but the same adaptation also provided the imaginative substrate for a system of "mimetic" expression, such as found in ritual and pantomime, and in proto-words, which performed an expressive function somewhat like the home signs of deaf non-signers. The hominid brain continued to adapt to the increasing importance and complexity of culture as human interactions with material culture became more complex; above all, this entailed a gradual expansion in the integrative systems of the brain, especially those involved in the metacognitive supervision of self-performances. This supported a style of embodied mimetic imagination that improved the coordination of shared activities such as fire tending, but also in rituals and reciprocal mimetic games. The time-depth of this mimetic adaptation, and its role in both the construction and acquisition of languages, explains the importance of mimetic expression in the media, religion, and politics. Spoken language evolved out of voco-mimesis, and emerged long after the more basic abilities needed to refine skill and share intentions, probably coinciding with the common ancestor of sapient humans. Self-monitoring and self-supervised practice were necessary

  17. Estrategias de subsistencia en los momentos finales del Pleistoceno medio: el nivel XII de la Cova del Bolomor (La Valldigna, Valencia

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    Ruth BLASCO

    2009-08-01

    los homínidos de la Cova del Bolomor y contribuir al conocimiento de los modos de vida de los grupos humanos del Pleistoceno medio final.ABSTRACT: Bolomor Cave, located in Tavernes de la Valldigna (Valencia, offers one of the best faunal records in the second half of the Middle Pleistocene in the Iberian Peninsula. The cavity contains a sedimentary deposit composed of seventeen stratigraphical levels ranging from OIS 9 to OIS 5e. This wide chronological sequence allows to deal with different issues related to human groups this period and their relationship with the environment. Specifically, from zooarchaeological study of level XII (OIS 6, we have reconstructed the anthropic sequence of obtaining and processing of faunal resources. Thus, different subsistence strategies carried out by hominids to obtain the animals were identified. These practices range from scavenging to the hunting and include the supply of small prey such as birds (Cygnus olor or leporids (Oryctolagus cuniculus. This variability of strategies could be interpreted as the great adaptability that possesses these groups to take advantage of the opportunities the environment offers. It was also noted the existence of systematic patterns well both in the utilization of faunal external resources (skin, meat, tendons and the obtaining of internal resources (marrow. Many of the diagnostic elements that demonstrate the anthropic breakage at level XII show systematization both in areas and in specific anatomical parts. The existence of morphologies repeated in some skeletal elements indicates a high degree of standardization at the time of bone breakage. This reiteration could imply the existence of learning mechanisms or transmission of information within the group in this chronological period. Overall, this study aims to provide data about the subsistence strategies of hominids in Bolomor Cave and contribute to knowledge about the way of life of human groups in the Last Middle Pleistocene.

  18. Land - Ocean Climate Linkages and the Human Evolution - New ICDP and IODP Drilling Initiatives in the East African Rift Valley and SW Indian Ocean

    Science.gov (United States)

    Zahn, R.; Feibel, C.; Co-Pis, Icdp/Iodp

    2009-04-01

    The past 5 Ma were marked by systematic shifts towards colder climates and concomitant reorganizations in ocean circulation and marine heat transports. Some of the changes involved plate-tectonic shifts such as the closure of the Panamanian Isthmus and restructuring of the Indonesian archipelago that affected inter-ocean communications and altered the world ocean circulation. These changes induced ocean-atmosphere feedbacks with consequences for climates globally and locally. Two new ICDP and IODP drilling initiatives target these developments from the perspectives of marine and terrestrial palaeoclimatology and the human evolution. The ICDP drilling initiative HSPDP ("Hominid Sites and Paleolakes Drilling Project"; ICDP ref. no. 10/07) targets lacustrine depocentres in Ethiopia (Hadar) and Kenya (West Turkana, Olorgesailie, Magadi) to retrieve sedimentary sequences close to the places and times where various species of hominins lived over currently available outcrop records. The records will provide a spatially resolved record of the East African environmental history in conjunction with climate variability at orbital (Milankovitch) and sub-orbital (ENSO decadal) time scales. HSPDP specifically aims at (1) compiling master chronologies for outcrops around each of the depocentres; (2) assessing which aspects of the paleoenvironmental records are a function of local origin (hydrology, hydrogeology) and which are linked with regional or larger-scale signals; (3) correlating broad-scale patterns of hominin phylogeny with the global beat of climate variability and (4) correlating regional shifts in the hominin fossil and archaeological record with more local patterns of paleoenvironmental change. Ultimately the aim is to test hypotheses that link physical and cultural adaptations in the course of the hominin evolution to local environmental change and variability. The IODP initiative SAFARI ("Southern African Climates, Agulhas Warm Water Transports and Retroflection

  19. Morfología comparada de los dientes humanos fósiles de Ibeas (Sierra de Atapuerca, Burgos

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    Bermúdez de Castro, J. M.

    1987-08-01

    Full Text Available This paper contains a morphological and comparative study of 68 human fossil teeth recovered from the "Sima de los Huesos" site of the Cueva Mayor-Cueva del Silo karst system (Sierra de Atapuerca, Ibeas de Juarros, Burgos. The morphology of the Ibeas teeth conforms with a pattern of expansion of the anterior dentition characterizing all the Middle Pleistocene human populations, and with a pattern of structural reduction of the posterior teeth characterizing the European population of that period. The Ibeas teeth share several morphological traits with those of other European, North African and Asian Middle Pleistocene fossils. However, the tooth morphology of the European group, in which the Ibeas fossils are included, shows remarkable differences with that of the other groups. This fact permits to reinforce the thesis that a distinctive hominid lineage was established in Europe during the Middle Pleistocene. On the other hand, the Ibeas teeth bring forward new evidence to support the hypothesis of a close filogenetic relationship between the Middle Pleistocene European population and the Nearderthals and, accordingly, of a local evolution during that period and the Early Upper Pleistocene.Este trabajo contiene el estudio morfológico comparado de un total de 68 dientes humanos fósiles recuperados en la Sima de los Huesos, yacimiento situado en el sistema kárstico Cueva Mayor-Cueva del Silo (Sierra de Atapuerca, Ibeas de Juarros, Burgos. La morfología de los dientes de Ibeas se ajusta a un modelo de expansión de la dentición anterior que caracteriza a todas las poblaciones humanas del Pleistoceno medio, y a un modelo de reducción estructural de la dentición posterior que caracteriza a la población europea de dicho periodo. Los dientes de Ibeas comparten diversos rasgos morfológicos con los dientes de otros fósiles mesopleistocenos de Europa, norte de Africa y este de Asia. Sin embargo, el grupo europeo, en el que se incluyen los f

  20. Hacia una nueva conceptualización evolutiva de la comunicación «cultural» Communicating Culture: An Evolutionary Explanation

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    James James Lull

    2011-03-01

    together by communication links. Can the information-sharing behavior of our species ever be brought into broader perspective and eventually foster greater harmony for all humankind? The authors argue that the answer to this question is «yes». Culture provides the necessary space for social negotiation and change. Advanced communication ability is the means by which this necessary cultural work is perpetually accomplished. A non-deterministic understanding of culture must be acknowledged from the outset. Cultural life differs greatly from biological conditions. Even under repressive conditions, culture is not determined the same way viral infections ravage biological bodies or computers. Technological advances in communication do not simply reinforce and intensify top-down, dominant cultural messages as theories of imperialism, memetic transmission, or social contagion contend. The pace of cultural development over the past 10,000 years has been particularly fast compared to any other time since hominids split from our common ancestor with chimpanzees millions of years ago. Our species’ unique skill as communicators in the dynamic technological and cultural environment of today offers real hope for retrieving the primordial affinities that unite us all.

  1. Highlights from Johannesburg, Gauteng Province, South Africa

    Science.gov (United States)

    2002-01-01

    Although the extraction of mineral wealth has been the major influence in the history of Johannesburg and the surrounding Witwatersrand regions (with about 45% of all gold ever mined coming from there), the discovery of now-famous hominid fossils at the Sterkfontein Caves, and the convening of the world's largest-ever conference on environment and development, are setting a new stage for the future. The United Nations began the second Development and Environment Conference in Johannesburg on August 26, 2002. This meeting addresses the implementation of international goals to fight poverty and protect the global environment that were established at the first such conference held in Rio de Janeiro in 1992. The Johannesburg summit involves about forty thousand participants, and perhaps 100 world leaders. One of several official opening ceremonies for the conference was held at the Sterkfontein Caves to recognize the outstanding universal value of the paleo-anthropological fossils found there.These views from the Multi-angle Imaging SpectroRadiometer (MISR) highlight a number of the land use, vegetation, and geological features found within Gauteng Province (including the urban center of Johannesburg and the capital city Pretoria) and parts of the North West and Free State Provinces. The image on the right displays vegetation in red hues and is a false-color view utilizing data from MISR's near-infrared, red and blue bands. Both the natural-color view (left) and the false-color version were acquired by MISR's nadir camera on June 16, 2002. The urban areas appear as gray-colored pixels in the natural-color view, and exhibit colors corresponding with the relative abundance of vegetation found in the urban parts of this arid region.The mountains trending east-west near the center of the images extend from Pretoria in the east to Rustenberg in the west. These ranges, the Magaliesberg and Witwatersberg, separate the low-lying, hotter bushveld to the north from the cooler

  2. Olduvai Gorge, Shaded Relief and Colored Height

    Science.gov (United States)

    2004-01-01

    Three striking and important areas of Tanzania in eastern Africa are shown in this color-coded shaded relief image from the Shuttle Radar Topography Mission. The largest circular feature in the center right is the caldera, or central crater, of the extinct volcano Ngorongoro. It is surrounded by a number of smaller volcanoes, all associated with the Great Rift Valley, a geologic fault system that extends for about 4,830 kilometers (2,995 miles) from Syria to central Mozambique. Ngorongoro's caldera is 22.5 kilometers (14 miles) across at its widest point and is 610 meters (2,000 feet) deep. Its floor is very level, holding a lake fed by streams running down the caldera wall. It is part of the Ngorongoro Conservation Area and is home to over 75,000 animals. The lakes south of the crater are Lake Eyasi and Lake Manyara, also part of the conservation area. The relatively smooth region in the upper left of the image is the Serengeti National Park, the largest in Tanzania. The park encompasses the main part of the Serengeti ecosystem, supporting the greatest remaining concentration of plains game in Africa including more than 3,000,000 large mammals. The animals roam the park freely and in the spectacular migrations, huge herds of wild animals move to other areas of the park in search of greener grazing grounds (requiring over 4,000 tons of grass each day) and water. The faint, nearly horizontal line near the center of the image is Olduvai Gorge, made famous by the discovery of remains of the earliest humans to exist. Between 1.9 and 1.2 million years ago a salt lake occupied this area, followed by the appearance of fresh water streams and small ponds. Exposed deposits show rich fossil fauna, many hominid remains and items belonging to one of the oldest stone tool technologies, called Olduwan. The time span of the objects recovered dates from 2,100,000 to 15,000 years ago. Two visualization methods were combined to produce the image: shading and color coding of

  3. Variability of knapping methods and technological change in the Middle Palaeolithic of the Abric Romani (Capellades, Barcelona

    Directory of Open Access Journals (Sweden)

    Vaquero, Manuel

    1999-12-01

    Full Text Available Lithic reduction sequences are a fundamental topic in palaeolithic research, since they provide data on the behavioural capabilities of early hominids. This paper studies the variability of lithic reduction strategies in the Abric Romaní (Capellades, Barcelona. This site has an extensive stratigraphic sequence, dated between 40 and 70 ka BP. In this sequence, mostly formed by travertine deposits, 27 archaeological levels have been identified, most of them corresponding to the Middle Palaeolithic. The Middle Palaeolithic levels so far excavated (B-L are dated between 40 and 52 ka BP, and suggest a reconstruction of the behavioural patterns of the Neanderthal groups preceding the early Upper Palaeolithic. The variability of the reduction sequences in a synchronous level and the changes over time are presented in the framework of the operative field concept. The results suggest that the technological changes in the Middle Palaeolithic can be explained by technical criteria that are reflected in different domains of analysis; these criteria are related to the degree of technical knowledge invested in lithic production and the range of technical options envisaged in each archaeological level.

    Las secuencias de talla lítica constituyen un tema fundamental en la investigación del Paleolítico, ya que proporcionan datos sobre las capacidades conductuales de los primeros homínidos. Este artículo estudia la variabilidad de las estrategias de talla en el Abric Romaní (Capellades, Barcelona, yacimiento que cuenta con una amplia secuencia estratigráfica datada entre los 40 y los 70 ka BP. En dicha secuencia, formada en su mayor parte por depósitos travertínicos, se han reconocido 27 niveles de ocupación, la mayor parte de los cuales atribuidos al Paleolítico Medio. Los niveles del Paleolítico Medio excavados hasta el momento (B-L, datados entre los 40 y los 52 ka BP, han permitido una reconstrucción de los patrones conductuales de los

  4. Messiniense: compleja y grave crisis ecologica

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    Aguirre, E.

    2003-08-01

    Full Text Available The «Messinian» is the last stratigraphic stage of the Miocene, lasting between 6.616.5 and 5.3 MaBP. Its redefinition and stratotype designation were problematic in the 1960s, in the frame of the IUGS International Commission on Stratigraphy (ICS revision works and the Project 110.25 of the International Geological Correlation Program (IGCP in the following decades. The interpretation of the regional Mediterranean stratigraphic sequence was debated. Many fossil mammal sites in Spain and other peri-Tethic regions, showing relevant events and intercontinental exchanges within that time span, add pressing questions to the essential need of correlating the continental bio,stratigraphic divisions to the marine based stratigraphic scale. Recent discovery of fossil hominids with early evidence of bipedal adaptation in East-and Central Africa with referred ages of nearly 6 MaBP, or more, makes the study of that age still more exciting. In the same time span, major palaeogeographic, geodynamic, palaeoclimatic and palaeoenvironmental events have been dated, that started been investigated 40 years ago also in connection to the late Miocene Mediterranean «Salinity Crisis»: isolation from the Atlantic Ocean, global sea leve1 lowering, continental accretion and orogeny, glaciation and vegetal cover deterioration. Severa1 models of sequenced interactions have been proposed. A comprehensive scenario is here attempted of these major events in the History of Earth and History of Life, with a calibration of nearly hundred thousand years.La división final del Mioceno, piso «Messiniense» -entre 6,5/6,6 Ma y 5,3 Ma-, presentó problema para su redefinición y la interpretación de sus secuencias estratigráficas en la década de 1960. Fue objeto de estudios profundos y diversos en el marco de programas de la Comisión Internacional de Estratigrafía (ICS y del Programa Internacional de Correlación Geológica en las décadas siguientes. Numerosos

  5. Language comprehension in ape and child.

    Science.gov (United States)

    Savage-Rumbaugh, E S; Murphy, J; Sevcik, R A; Brakke, K E; Williams, S L; Rumbaugh, D M

    1993-01-01

    required the ability to reverse work order as they did on sentences that did not require this capacity. These results are discussed in light of a model of the evolution of language that suggests that the potential for language comprehension preceded the appearance of speech by several million years at minimum. The onset of speech is linked to the appearance of fully adapted bipedalism, which necessitated reorientation of the laryngeal tract and made closure of the soft palate possible. For the first time, such closure permitted mammals to easily produce sounds that could be interpreted by the mammalian auditory system in a categorical manner. When these sounds were paired with the previously extant capacity to produce vowels, it became possible to form "bounded vowels" or sound units that could readily be discriminated as units by the auditory system. It is suggested that this physical adaptation allowed the extant cognitive capacity of the hominids to embark on a speech-like mode of communication.

  6. Book Reviews

    Directory of Open Access Journals (Sweden)

    Danker H. Schaareman

    1980-01-01

    . xvi + 329 pages. Maps, tables, plates, figures, index. - A. de Ruijter, S.F. Moore, Secular Ritual. Van Gorcum, Assen, 1977. 293 pp., B.G. Myerhoff (eds. - A. Ploeg, L.M. Serpenti, Cultivators in the swamps. Social structure and horticulture in a New Guinea society, Second edition. Van Gorcum, Assen, 1977, 308 pp., maps, tables, figures, glossary. - A. de Ruijter, R. Needham, Symbolic classifications. Goodyear Publishing Company Inc. Santa Monica, California. 1979. 78 pp. - Danker H. Schaareman, Urs Ramseyer, The art and culture of Bali. Oxford 1977: Oxford University Press. 265 pp., 405 pp., ill. - Anthony Shelton, E. Schwimmer, The Yearbook of Symbolic anthropology, London: C. Hurst and Co., 1978; pp. 230. - H. Steinhauer, M.A. Chlenov, Naselenie Molukkskix Ostrovov [The population of the Moluccas], Moscow 1976, 285 pp. - P. van de Velde, M.G. Leakey, The fossil hominids and an introduction to their context, 1968-1974, Oxford: Clarendon Press, 1978. Volume 1 of R.E. Leakey & G.Ll. Isaac (general editors: Koobi Fora - researches into geology, palaeontology, and human origins. 191 pages; 28 plates and numerous figures; tables; index., R.E. Leakey (eds. - Leontine E. Visser, P.A. Stott, Nature and man in South East Asia, 1978, S.O.A.S., London, 183 pp., fig., phot., subject index. - J.J. de Wolf, F. Bovenkerk, Toen en thans: De sociale wetenschappen in de jaren dertig en nu. Onder redactie van F. Bovenkerk, H.J.M. Claessen, B. van Heerikhuizen, A.J.F. Köbben, N. Wilterdink. 1978 Ambo, Baarn., H.J.M. Claessen, B. van Heerikhuizen (eds.

  7. Quaternary climate change on the northern margins of Saharo-Arabian Desert with possible impact on human evolution, evidence from Negev Desert speleothems, Israel

    Science.gov (United States)

    Vaks, A.; Bar-Matthews, M.; Ayalon, A.; Matthews, A.; Halicz, L.; Frumkin, A.

    2006-12-01

    : thinning laminae width of dateable speleothems from few tens of cm in northern Negev to less than 2 cm in the south; similarity of oxygen isotopic trends between desert speleothems and speleothems from Mediterranean climate; and δ18O - δ2H relationships of speleothem fluid inclusions that follow usually the Mediterranean Meteoric Water Line. The intensification of the mid-latitude cyclones that caused increased rainfall in northern Saharo-Arabian desert at 350-290 ka, 220-190 ka, 137-110 ka, and ~85 ka correlate to the peaks of monsoon activity in southern and central parts of the desert belt. We assume that during these events the Saharo-Arabian Desert significantly reduced its size, opening climatic windows for hominids and African animals to get out of the African continent. One of the evidences supporting this hypothesis is first appearance of the EMH out of the Africa at ~130 ka in Israeli caves Skhul and Qafzeh, during the peak of the humid period of 137-110 ka. The expanding aridity after 110 ka blocked the way back to Africa and may have driven the EMH further east and north.

  8. Communicating Climate Change: An Evolutionary Perspective

    Science.gov (United States)

    Peacock, K. A.; Byrne, J. M.; McDaniel, S.

    2012-12-01

    The most effective way to communicate the scientific "big picture" is to appeal to the intelligence and imagination of that large number of people who really want to know what science has to say, and who really would be likely to support enlightened policies if they were given an unflinching picture of the present human predicament. Staff writers at Life Magazine used to be told, "Never overestimate readers' information; never underestimate their intelligence." In the long run, whatever communications channels may be employed, the best hope of moving forward is to appeal to the intelligence of the public. (Media such as wikis, which invite participation, could be one of the best ways to do that.) There are two salient "big picture" facts to be communicated. The first is the ecological unsustainability of the present human condition. There is not the slightest possibility of a long-term future for a planetary-scale, technologically-intensive society of over 7 billion talking hominids that gets most of its free energy from the combustion of a one-time-only store of biotic waste products laid down in the strata hundreds of millions of years ago. Not only is this limited fuel supply running out, but its waste products are rapidly destabilizing the very climatic conditions that favoured the growth of our complex culture. As Homer-Dixon puts it, we are on the "cusp of a planetary-scale emergency"—obvious to earth scientists, but not obvious to all of even the best-intentioned members of the public. The second crucial fact is that our species' capacity to innovate (technologically, linguistically, socially), unique in the history of life on this planet, has up to now been our most effective survival tool and still remains our best chance for pulling through the present crisis. Herbert Spencer said that the most important adaptive trait is what he called "sagacity"—intelligent adaptability. But our sagacity now faces its toughest test, tougher than the harsh Ice Age in

  9. The “Sima del Elefante” cave site at Atapuerca (Spain

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    Huguet, R.

    2006-12-01

    Full Text Available The “Sima del Elefante” (TE site (Atapuerca, Spain is a major cave infill with a stratigraphic succession 25 m thick and 15 m wide, wealthy in animal bones and evidences of human occupation at different Pleistocene ages. TE site is under systematic excavation since 1996, and the inferior and superior levels are being dug up independently. The exposed section has been divided into 21 lito-stratigraphic units defined by major unconformities. Concerning the cave history, at least three main infill phases have been identified. The lower phase (TE8-TE14 is dated to Early Pleistocene (between 1.1 and 1.4 million years ago on the basis of inverse paleomagnetics and belonging to the later Early Pleistocene on the basis of biochronology. The TE lower phase is providing a rich faunal assemblage, and shows evidence of human occupation. A set of stone tools of flint, and possibly, calcareous, is being found at these levels. Hence, the lower part of the TE section documents early presence of hominids in Europe and constituted an important element in the understanding of human dispersions out-of-Africa. The middle phase (TE15-TE19 dated to Middle Pleistocene and it is further sud-divided into a basal part (TE15-TE17, still largely unexplored, but no vertebrate fossil record is present at this levels. Units TE18, and mainly TE19 unit, date to late Middle Pleistocene, and contain an abundant record of large mammals as well as stone tools included in calcareous breccias. The TE19 G level contains abundant pieces of charcoal, though verification of its antropic character is pending. Finally, the third and last sedimentary phase (TE20 and TE21 date to Last Pleistocene and it defined the final infilling of the cavity and soil formation. The chronological intervals represented in the fertile levels of the Sima del Elefante enlarge the temporal and biostratigraphic local succession at the Atapuerca Hill complex. The lower phase was deposited in a time previous to

  10. Diet, evolution and aging--the pathophysiologic effects of the post-agricultural inversion of the potassium-to-sodium and base-to-chloride ratios in the human diet.

    Science.gov (United States)

    Frassetto, L; Morris, R C; Sellmeyer, D E; Todd, K; Sebastian, A

    2001-10-01

    Theoretically, we humans should be better adapted physiologically to the diet our ancestors were exposed to during millions of years of hominid evolution than to the diet we have been eating since the agricultural revolution a mere 10,000 years ago, and since industrialization only 200 years ago. Among the many health problems resulting from this mismatch between our genetically determined nutritional requirements and our current diet, some might be a consequence in part of the deficiency of potassium alkali salts (K-base), which are amply present in the plant foods that our ancestors ate in abundance, and the exchange of those salts for sodium chloride (NaCl), which has been incorporated copiously into the contemporary diet, which at the same time is meager in K-base-rich plant foods. Deficiency of K-base in the diet increases the net systemic acid load imposed by the diet. We know that clinically-recognized chronic metabolic acidosis has deleterious effects on the body, including growth retardation in children, decreased muscle and bone mass in adults, and kidney stone formation, and that correction of acidosis can ameliorate those conditions. Is it possible that a lifetime of eating diets that deliver evolutionarily superphysiologic loads of acid to the body contribute to the decrease in bone and muscle mass, and growth hormone secretion, which occur normally with age? That is, are contemporary humans suffering from the consequences of chronic, diet-induced low-grade systemic metabolic acidosis? Our group has shown that contemporary net acid-producing diets do indeed characteristically produce a low-grade systemic metabolic acidosis in otherwise healthy adult subjects, and that the degree of acidosis increases with age, in relation to the normally occurring age-related decline in renal functional capacity. We also found that neutralization of the diet net acid load with dietary supplements of potassium bicarbonate (KHCO3) improved calcium and phosphorus balances

  11. Earth's glacial record and its tectonic setting

    Science.gov (United States)

    Eyles, N.

    1993-09-01

    such as the Tibetan Plateau and plate tectonic reorganizations have been identified as first-order controls. Initiation of the East Antarctic ice sheet, at about 36 Ma, is the result of the progressive thermal isolation of the continent combined with uplift along the Transantarctic Mountains. In the Northern Hemisphere, the upwarping of extensive passive margin plateaux around the margins of the newly-rifted North Atlantic may have amplified global climatic changes and set the scene for the growth of continental ice sheets after 2.5 Ma. Ice sheet growth and decay was driven by complexly interrelated changes in ocean circulation, Milankovitch orbital forcing and global geochemical cycles. It is arguable whether continental glaciations of the Northern Hemisphere, and the evolution of hominids, would have occurred without the necessary precondition of tectonic uplift.

  12. Considérations ontogénétiques et phylogénétiques concernant l’origine de la parole Ontogenetic and phylogenetic considerations concerning the origin of speech

    Directory of Open Access Journals (Sweden)

    Jean Granat

    2011-10-01

    solved: If we suppose that our ancestors (and distant cousins controlled their larynx and vocal tract in the same way as present-day humans, did the geometry of their vocal tract allow them to produce the universal sound structures of the languages spoken today? We analyzed 31 skulls from now to 1.5 Ma (millions years BP (Before Present for fossil hominids available at the Muséedel’Homme in Paris or in the literature: (1 10-30 ka BP: modern humans: Paleolithic; (2 90-200 ka BP: anatomically modern humans; (3 45-90 ka BP: Neanderthals; (4 1.5 Ma BP: Homoergaster; These skulls are all well kept and possess a jaw in the majority of cases but the vertebral column has been reconstituted. We attempt to: (1 Localize hyoid bone and then glottis position; (2 Reconstitute a vocal tract model in a plausible way using an articulatory model; (3 Quantify the acoustic capabilities of this reconstituted vocal tract. For this purpose, we combine phylogenesis and ontogenesis. We are in a position to state that our ancestors and distant cousins were equipped with a vocal tract that could produce the same variety of vowel sounds as we can today: the vowels /i a u/. The vocal tract morphology has been favorable to the emergence and production of speech since several hundreds of thousands of years. But how to know to what extent they mastered the control skills needed to produce speech? New lines of research are proposed in which orofacial abilities necessary to the emergence of speech are linked to a precursor mechanism dedicated to feeding (masticating-swallowing movements.