Full Text Available A nivel demográfico, los resultados clásicos de los modelos matriciales separan a las especies de tiempo generacional corto de las especies de tiempo generacional largo en cuanto a la importancia de la supervivencia adulta para la dinámica poblacional. Específicamente, la supervivencia adulta no debería contribuir de manera importante en la tasa de cambio poblacional de especies de tiempo generacional corto. Sin embargo, Yoccoz et al. (1998, Research Population Ecology 40: 107-121 propusieron que la supervivencia adulta sería el parámetro demográfico más importante para determinar la tasa de cambio poblacional en pequeños roedores cuando se toma en consideración una escala de tiempo mensual. Con el fin de poner a prueba esta hipótesis en este trabajo, utilizamos cinco años de datos de captura-marcaje-recaptura para estimar la supervivencia y la maduración de las hembras del lauchón orejudo, Phyllotis darwini, en una localidad de Chile central. El análisis mostró que las probabilidades de supervivencia disminuían con el promedio anual de la cantidad de lluvia y que las probabilidades de maduración disminuían con la densidad poblacional. Basados en las probabilidades de supervivencia y maduración, construimos un modelo matricial estacional para medir la importancia relativa de cada parámetro demográfico en el ciclo de vida de la especie a través de un análisis de perturbación. A fin de reflejar la variabilidad estacional del ambiente, dos estaciones fueron incorporadas en el modelo matricial: una estación de lluvia de cinco meses y una estación seca. Se observó que la supervivencia adulta era en efecto el parámetro demográfico con la elasticidad más fuerte. Por lo tanto, estos resultados apoyan la hipótesis de Yoccoz et al. (1998Classic results of matrix models predict that, in species with a long generation time, adult survival should be the demographic parameter driving population dynamics whereas, in species
Full Text Available Population density and reproduction were studied in two leaf-eared mice (Phyllotis spp. in the Peruvian locality known as Lomas de Lachay. Density varied between 0-3 individuals ha-1 in P. andium, and between 0-12 individuals ha-1 in P. amicus. An annual cycle of population abundance was observed in both species. Phyllotis amicus showed no seasonal reproductive activity, but P. andium had seasonal reproduction with pregnant females principally observed between July and September. Differences in juvenile weight were related to litter size. It is likely that two young was the optimal litter size in the harsh and seasonal xeric environment of Lomas de Lachay. Our results suggest that P. amicus maintains low, highly dispersed populations in a harsh environment, and can reproduce at any time of the year, whereas P. andium appears to be a more irruptive species closely tied to rainfall patternsLa densidad poblacional y reproducción de dos ratones orejudos (Phyllotis spp. fueron estudiadas en la localidad peruana Lomas de Lachay. La densidad varió entre 0-3 individuos ha-1 en P. andium, y entre 0-12 individuos ha-1 en P. amicus. En ambas especies se observaron cambios poblacionales que sugieren la existencia de ciclos anuales en la abundancia poblacional. El patrón reproductivo en las dos especies de Phyllotis fue claramente distinto. Phyllotis amicus mostró una actividad reproductiva no estacional, mientras que P. andium tuvo una reproducción estacional observándose hembras preñadas principalmente entre julio y septiembre. La diferencia en el peso de los juveniles estuvo relacionada con el tamaño de la camada. Es probable que en las Lomas de Lachay el tamaño de camada óptimo sea de dos individuos. Nuestros resultados sugieren que P. amicus es una especie que mantiene poblaciones bajas, altamente dispersas en áreas desérticas, y que puede reproducirse durante todo el año; mientras que P. andium parece ser una especie que irrumpe más en
Tinn, Oive, 1966-
Intervjuu Eesti looduseuurijate seltsi presidendi, paleontoloog Oive Tinniga Eesti Looduseuurijate seltsi tegemistest ning Charles Darwini raamatu "Inimese põlvnemine ja suguline valik" toimetamisest
Cambridgeþi ülikooli eestvedamisel on digitaliseeritud umbes 50 000 lehekülge tekste ja 40 000 kujutist nii originaalväljaannetest kui ka seni laiemalt avaldamata materjalidest. Darwini tööd on aadressil: http://darwin-online.org.uk
Schmitz, Patrick; Cibois, Alice; Landry, Bernard
To gain insight into the early stages of speciation, we reconstructed a DNA-based phylogeny, using combined mitochondrial (cytochrome c oxidase subunits I and II: 1008 bp) and nuclear (elongation factor 1-alpha and wingless: 1062 bp) markers of populations of the moth Galagete darwini endemic to the Galápagos, which belongs to an insular radiation similar in size to that of Darwin's finches. Adults of G. darwini were collected in the arid lowlands of 11 of the Galápagos Islands (Baltra, Española, Fernandina, Floreana, Isabela, Pinta, Pinzón, San Cristobal, Santa Cruz, Santiago and Seymour) and the humid highlands of a subset of 5 of them (Fernandina, Floreana, Isabela, Santa Cruz and Santiago). The combined phylogeographic analysis surprisingly revealed that G. darwini populations at higher elevation on the western islands (Fernandina, Isabela and Santiago) represent a distinct lineage from the one in the low arid zones of these same islands. This is the first reported case in the archipelago of genetic cryptic differentiation correlated with elevation on the western Galápagos volcanoes.
Marcelo E. KUN, Carla PIANTONI, John D. KRENZ, Nora R. IBARGÜENGOYTÍA
Full Text Available Our study investigated the diet of the southernmost gecko in the world, Homonota darwini. Fifty-three specimens were captured during spring and summer in four locations in Patagonia, Argentina. The stomach contents of the specimens were identified, and we found that prey consisted of six main groups: Coleoptera, Hymenoptera, Homoptera and Araneae, and the adults and larvae of moth Lepidoptera. Lepidoptera was the major dietary component. The presence of ants and moths as common prey suggests an ambush feeding strategy. In spring, females consumed more ants than males although no other dietary differences between males and females were evident. We found nine geckos with empty stomachs and six parasitized by nematodes. Presence of empty stomachs corroborates previous observations of other nocturnal geckos and non-gecko lizards. Reduced foraging success of nocturnal lizards could be due to difficulty in prey detection due to dim light, reduced or erratic activity of insect prey at night, or shorter activity times of geckos relative to diurnal success. Sex and season were not associated with the incidence of empty stomachs. Principal component analysis showed that four food alternatives correlated with season. The constraint of nocturnality, coupled with low night-time temperatures restricting feeding to only a few hours after sunset, appear to have caused a generality of diet which may limit energy acquisition. We conclude that H. darwini is an arthropod generalist and likely an ambush forager, as are many other nocturnal gekkonids [Current Zoology 56 (4: 406–410, 2010].
Full Text Available Interspecific coevolution is well described, but we know significantly less about how multiple traits coevolve within a species, particularly between behavioral traits and biomechanical properties of animals' "extended phenotypes". In orb weaving spiders, coevolution of spider behavior with ecological and physical traits of their webs is expected. Darwin's bark spider (Caerostris darwini bridges large water bodies, building the largest known orb webs utilizing the toughest known silk. Here, we examine C. darwini web building behaviors to establish how bridge lines are formed over water. We also test the prediction that this spider's unique web ecology and architecture coevolved with new web building behaviors.We observed C. darwini in its natural habitat and filmed web building. We observed 90 web building events, and compared web building behaviors to other species of orb web spiders.Caerostris darwini uses a unique set of behaviors, some unknown in other spiders, to construct its enormous webs. First, the spiders release unusually large amounts of bridging silk into the air, which is then carried downwind, across the water body, establishing bridge lines. Second, the spiders perform almost no web site exploration. Third, they construct the orb capture area below the initial bridge line. In contrast to all known orb-weavers, the web hub is therefore not part of the initial bridge line but is instead built de novo. Fourth, the orb contains two types of radial threads, with those in the upper half of the web doubled. These unique behaviors result in a giant, yet rather simplified web. Our results continue to build evidence for the coevolution of behavioral (web building, ecological (web microhabitat and biomaterial (silk biomechanics traits that combined allow C. darwini to occupy a unique niche among spiders.
Dietas de Abrothrix andinus, Phyllotis xanthopygus (Rodentia y Lepus europaeus (Lagomorpha en un ambiente altoandino de Chile Feeding habits of Abrothrix andinus, Phyllotis xanthopygus (Rodentia and Lepus europaeus (Lagomorpha in an Andean environment of Chile
Full Text Available Los roedores nativos Abrothrix andinus, Phyllotis xanthopygus y el lagomorfo introducido Lepus europaeus, coexisten en ambientes altoandinos del centro-norte de Chile, donde la disponibilidad de alimento es escasa y distribuida heterogéneamente en el paisaje. Propusimos que en estos ambientes las especies en estudio se comportarían como herbívoros generalistas y que existiría una alta sobreposición en la dieta entre la liebre y los roedores nativos. El objetivo de este trabajo fue documentar la composición de la dieta de las tres especies y determinar su amplitud, preferencia y sobreposición en la dieta a partir del análisis microhistológico de heces frescas. Los resultados indican que las tres especies se comportaron como herbívoros-folívoros, siendo la dieta de L. europaeus la de mayor amplitud trófica. Abrothrix andinus seleccionó todos los ítemes que consume, mientras que P. xanthopygus y L. europaeus realizaron un consumo más oportunista. La mayor sobreposición en la dieta se observó entre los roedores nativosThe native rodents Abrothrix andinus, Phyllotis xanthopygus and the introduced lagomorph Lepus europaeus coexist in the highlands of north-central Chile, where food availability is scarce. We hypothesized that in these environments, the studied species would behave as generalist herbivores and where the diet of native rodents would overlap that of hares greatly. The aim of this study was to quantify feeding habits, amplitude, diet preferences and overlap of these three species through microhistological analysis of fresh faeces. While all three species behaved as herbivore-folivores, L. europaeus showed the largest niche breath. Abrothrix andinus selected all consumed items, while P. xanthopygus and L. europaeus exhibited a more opportunistic consumption food items. The highest diet overlap was observed between native rodents
Full Text Available Colonization across the Galápagos Islands by the carpenter bee (Xylocopa darwini was reconstructed based on distribution of mitochondrial haplotypes (cytochrome oxidase II (COII sequences and haplotype lineages. A total of 12 haplotypes were found in 118 individuals of X. darwini. Distributional, phylogenetic and phylogeographic analyses suggest early colonization of most islands followed by historical isolation in two main groups: eastern and central-western islands. Evidence of recurrent inter-island colonization of haplotypes is largely lacking, despite strong flight capability and ecological amplitude of the species. Recent palaeogeographic data suggest that several of the current islands were connected in the past and thus the isolation pattern may have been even more pronounced. A contrast analysis was also carried out on 10 animal groups of the Galápagos Islands, and on haplotype colonization of seven animal and plant species from several oceanic archipelagos (the Galápagos, Azores, Canary Islands. New colonization metrics on the number of potential vs. inferred colonization events revealed that the Galápagos carpenter bee shows one of the most significant examples of geographic isolation.
Tania Anaid Gutiérrez-García
Full Text Available Central America is an ideal region for comparative phylogeographic studies because of its intricate geologic and biogeographic history, diversity of habitats and dynamic climatic and tectonic history. The aim of this work was to assess the phylogeography of two rodents codistributed throughout Central America, in order to identify if they show concordant genetic and phylogeographic patterns. The synopsis includes four parts: (1 an overview of the field of comparative phylogeography; (2 a detailed review that describes how genetic and geologic studies can be combined to elucidate general patterns of the biogeographic and evolutionary history of Central America; and a phylogeographic analysis of two species at both the (3 intraspecific and (4 comparative phylogeographic levels. The last incorporates specific ecological features and evaluates their influence on the species’ genetic patterns. Results showed a concordant genetic structure influenced by geographic distance for both rodents, but dissimilar dispersal patterns due to ecological features and life history.
Gallardo, Pedro A; Cortes, Arturo; Bozinovic, Francisco
We examined the phenotypic flexibility of field urine osmolality (Uosm) in response to seasonal rainfall and the experimental expression of renal aquaporins (AQPs) in the leaf-eared mouse Phyllotis darwini, a South American desert-dwelling rodent, through an integrative study at both the cellular and the organismal level. Field Uosm was higher in summer than in winter. Fall and winter Uosm were not significantly different. During a rainy year, winter Uosm was 2,140 +/- 82.3 mOsm kg(-1); the corresponding value in a dry year was 2,569 +/- 61.3 mOsm kg(-1). During the summer, the mean Uosm in a rainy year was 3,321 +/- 71.5 mOsm kg(-1), and in a dry year it was 3,604 +/- 107.2 mOsm kg(-1). The distribution of AQP-2, AQP-3, and AQP-4 was similar to that described for mouse and rat kidneys and confined to principal cells in cortex and inner medullary collecting-duct cells. AQP-4 immunoreactivity was unaltered by the state of water balance. Relative to water loading, dehydration induced an increase in AQP-2 immunoreactivity and protein abundance. Although more discrete, AQP-3 immunolabeling was also increased by dehydration. We now reveal how the integration of flexible renal mechanisms acting at the cellular and organismal level allow a small desert-dwelling mammal to cope with seasonal and yearly (El Nino) water availability in its semiarid habitat.
Muñoz-Pedreros, Andrés; Yáñez, José; Norambuena, Heraldo V; Zúñiga, Alfredo
The South American grey fox Lycalopex griseus is a canid widely distributed in southern South America; however, some aspects of its biology are still poorly known. We studied the diet and density of L. griseus in the Lago Peñuelas Biosphere Reserve, in Central Chile. The trophic niche breadth was B = 6.16 (B sta = 0.47) and prey diversity was H' = 2.46 (H max ' = 3.17, J' = 0.78). The highest proportions of prey consumed in the diet were Oryctolagus cuniculus (52.21%) and other mammals (32.78%). We compared these results with a latitudinal gradient of diet results for this species in Chile. L. griseus eats mostly mammals (>90% of total prey), consuming the rodent Phyllotis darwini and reptiles in the northern zone; Oryctolagus cuniculus, Octodon degus and Abrocoma bennetti in the central zone; Abrothrix spp. and lagomorphs in the southern zone; and Lepus capensis and Ovis aries in the austral zone. The estimated density of L. griseus in Lago Peñuelas NR was 1.3 foxes/km 2 . © 2017 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.
Loayza, Andrea P.; Squeo, Francisco A.
Scatter-hoarding rodents can act as both predators and dispersers for many large-seeded plants because they cache seeds for future use, but occasionally forget them in sites with high survival and establishment probabilities. The most important fruit or seed trait influencing rodent foraging behavior is seed size; rodents prefer large seeds because they have higher nutritional content, but this preference can be counterbalanced by the higher costs of handling larger seeds. We designed a cafeteria experiment to assess whether fruit and seed size of Myrcianthes coquimbensis, an endangered desert shrub, influence the decision-making process during foraging by three species of scatter-hoarding rodents differing in body size: Abrothrix olivaceus, Phyllotis darwini and Octodon degus. We found that the size of fruits and seeds influenced foraging behavior in the three rodent species; the probability of a fruit being harvested and hoarded was higher for larger fruits than for smaller ones. Patterns of fruit size preference were not affected by rodent size; all species were able to hoard fruits within the entire range of sizes offered. Finally, fruit and seed size had no effect on the probability of seed predation, rodents typically ate only the fleshy pulp of the fruits offered and discarded whole, intact seeds. In conclusion, our results reveal that larger M. coquimbensis fruits have higher probabilities of being harvested, and ultimately of its seeds being hoarded and dispersed by scatter-hoarding rodents. As this plant has no other dispersers, rodents play an important role in its recruitment dynamics. PMID:27861550
Ameerika Teaduse Edendamise Assotsiatsiooni (AAA) konverentsil esitatud uusimatest teadusuuringutest. Artiklid: Mona Lisa naeratuse saladus paljastatud ; Lesbilised Jaapani makaagid seljatavad Darwini ; Linnud õpivad uusi laule uue partneri leidmiseks
Long-term research in Bosque Fray Jorge National Park: Twenty years studying the role of biotic and abiotic factors in a Chilean semiarid scrubland Investigación de largo plazo en el Parque Nacional Bosque Fray Jorge: Veinte años estudiando el rol de los factores bióticos y abióticos en un matorral chileno semiárido
JULIO R GUTIÉRREZ
Full Text Available Since 1989, we have conducted a large-scale ecological experiment in semiarid thorn scrub of a national park in north-central Chile. Initially, we focused on the role of biotic interactions including predation, interspecific competition, and herbivory in small mammal and plant components of the community. We utilized a reductionist approach with replicated 0.56 ha fenced grids that selectively excluded vertebrate predators and/or larger small mammal herbivores such as the degu, Octodon degus. Although we detected small transitory effects of predator exclusions on degu survival and numbers, other species failed to show responses. Similarly, interspecific competition (i.e., degus with other small mammals had no detectable numerical effects (although some behavioral responses occurred, and degu-exclusions had relatively small effects on various plant components. Modeling approaches indicate that abiotic factors play a determining role in the dynamics of principal small mammal species such as O. degus and the leaf-eared mouse (Phyllotis darwini. In turn, these are mainly related to aperiodic pulses of higher rainfall (usually during El Niño events which trigger ephemeral plant growth; a food addition experiment in 1997-2000 verified the importance of precipitation as a determinant of food availability. Since 2004, we have expanded long-term monitoring efforts to other important community components including birds and insects in order to understand effects of abiotic factors on them; we report some of the first results of comprehensive surveys on the former in this region. Finally, we recently shifted focus to documenting effects of exotic lagomorphs in the park. We installed additional treatments selectively excluding small mammals, lagomorphs, or both, from replicated grids in order to evaluate putative herbivore impacts. In conjunction with increased annual rainfall since 2000, we predict that introduced lagomorphs will have increasing impacts
Schneider, Heinrich, 1925-2013
Süsteemsusideede ajaloolisest arengust, Aristotelese, R. Descartes'i ja C. Darwini õpetustest ning füsikokeemilisest koolkonnast. Süsteemkäsitluse rakendumisest õigusteaduses. Sünergeetikast ja I. Prigogine'i osast selle rajamisel
Hallas-Murula, Karin, 1957-
2002. a. novembris Londonis toimunud Briti Nõukogu korraldatud seminarist "Managing Museums and Galleries of the 21st Century", mille rõhk oli kunstimuuseumidel. Inglise muuseumidest: Tate Modern, Baltic, British Museum, Victoria & Alberti muuseum, Londoni loodusmuuseumi Darwini keskus
Vaher, Vaapo, 1945-
Arvustus: Roberts, Andrew. Sõjatorm : uus II maailmasõja ajalugu. Tallinn : Varrak, 2011 ; Tannberg, Tõnu. Eesti mees Vene kroonus : uurimusi Baltikumi ja Venemaa sõjaajaloost impeeriumi perioodil 1721–1917. Tartu : Ilmamaa, 2011 ; Dennett, Daniel Clement. Darwini ohtlik idee. Tallinn : Varrak, 2011
Kivi, Aita, 1954-
Sisu : Margaret Atwood. Pime palgamõrvar; Sebastian Faulks. Charlotte Gray; Peter Carey. Oscar ja Lucinda; Kurt Vonnegut. Sinihabe; Aita Kivi. Jumalakäpp; Aita Kivi. Lummus; Raymond Radiguet. Saatan ihus; Wendu Northcutt. Darwini auhinnad; Merike Hanni. Ümberõpe; Merike Hanni. Tori hobune; Friedrich Schiller. Maria Stuart
Ortiz, P. E.; Teta, P.
A micromammal archaeological sequence (2120 f 120 to 780 f 100 years BP) from Inca Cueva 5 site (23" 05' S - 65" 27' W; 3700 m.a.s.l., Jujuy Province, Argentina) was studied. The following mammalian taxa were recorded: Order Didelphimorphia, Family Didelphidae, Thylamys cf. T. pallidior; Order Rodentia, Family Muridae, Akodon cf. A. albiventer, Andinomys edax, Auliscomys sublimis, Calomys lepidus, Neotomys ebriosus, Phyllotis sp.; Family Caviidae, Cavia cf. C. tschudii, Galea musteloides; Fam...
Kuch, M.; Rohland, N.; Betancourt, J.L.; Latorre, C.; Steppan, S.; Poinar, H.N.
DNA was extracted from an 11 700-year-old rodent midden from the Atacama Desert, Chile and the chloroplast and animal mitochondrial DNA (mtDNA) gene sequences were analysed to investigate the floral environment surrounding the midden, and the identity of the midden agent. The plant sequences, together with the macroscopic identifications, suggest the presence of 13 plant families and three orders that no longer exist today at the midden locality, and thus point to a much more diverse and humid climate 11 700 years ago. The mtDNA sequences suggest the presence of at least four different vertebrates, which have been putatively identified as a camelid (vicuna), two rodents (Phyllotis and Abrocoma), and a cardinal bird (Passeriformes). To identify the midden agent, DNA was extracted from pooled faecal pellets, three small overlapping fragments of the mitochondrial cytochrome b gene were amplified and multiple clones were sequenced. These results were analysed along with complete cytochrome b sequences for several modern Phyllotis species to place the midden sequence phylogenetically. The results identified the midden agent as belonging to an ancestral P. limatus. Today, P. limatus is not found at the midden locality but it can be found 100 km to the north, indicating at least a small range shift. The more extensive sampling of modern Phyllotis reinforces the suggestion that P. limatus is recently derived from a peripheral isolate.
Blázquez Paniagua, Francisco
In Spain, during Franco’s dictatorship (1939-1975) the teaching and divulgation of science were subordinated to the Catholic religion and many books defended a theistic and creationistic point of view of Biology that accepted a literal interpretation of the Book of Genesis and denied the theory of evolution, especially as it relates to human origin. This article is devoted to the main books and characteristics of this way of thinking which reproduced arguments and metaphors of the Pre-Darwini...
Creationist theories are still present in the United States and in Europe. The Darwinian theory of evolution is often considered as the starting point of important debates between religions and evolutionists. In this paper, we are principally interested in evolutionary creationism (or theistic evolutionism). The existence of a divine design in nature, the spiritual status of human beings and the emergence of human species as the purpose of evolution are some of those debates. The post-Darwini...
Kivi, Aita, 1954-
Sisu : Anton Nigov [Tõnu Õnnepalu]. Harjutused; Elme Väljaste. Kiusatus; Reet Kudu. Täiskuu ja tänavalatern; Vaapo Vaher. Surmakuul & seemnepurse; Jelena Skulskaja. Vene rulett; Inge Ojala. Asendusema ja olematud lapsed; Inge Ojala. Andesta - ma kasvasin tänaval; Barbara Vine. Korstnapühkija poeg; Charlotte Bingham. Suveaeg; Lisa Gardner. Täiuslik abikaasa; Wendy Northcutt. Darwini auhinnad 2; Dean Foster. Euroopa riikide etikett ja tavad; J. P. Donleavy. Naine, kellele meeldisid puhtad tualettruumid; Karin Altvegen. Kadunud hing; Grant Naylor. Punane kääbus; Dylan Evans. Emotsioon. Sentimenditeooria
Cruz, Félix B.
Full Text Available Poco es lo que se conoce sobre la variación de la temperatura corporal de lagartos nocturnos. Se sabe que algunos lagartos nocturnos termorregulan durante el día. El tamaño corporal y el comportamiento, a su vez, pueden estar relacionados con la inercia térmica. Individuos de Homonota borelli y H. darwini fueron expuestos a tres situaciones, a refugios cálidos (la temperatura nunca fue menor a los 34 ºC, b refugios con una temperatura inferior a los 28-30 ºC, y c se les permitió escoger entre cada una de las opciones anteriores. La temperatura corporal en general y el patrón diario fueron similares en ambas especies siendo más altas durante el día. Cuando los lagartos eligieron los refugios, se observaron diferencias entre las especies, H. borelli usó más los refugios con fuente de calor en tanto que H. darwini usó refugios sin fuente de calor. El tamaño corporal y la distribución geográfica podrían estar relacionados con las diferencias observadas. Very little is known about diel variation in body temperature among nocturnal lizards. Some nocturnal lizards thermoregulate during the day, and body size plus behaviour may be related to the amount of thermal inertia. Lizards of the species Homonota borelli and H. darwini were either exposed to three different situations a a heated retreat site (never below than 34 º C, b a retreat with a temperature lower than 28-30 º C, and c where lizards were allowed to choose between a warm or a cool retreat. Body temperatures and diel pattern were similar for both species. Body temperatures were higher during the day. When lizards choose for retreats, differences were observed, H. darwini preferred cool retreats, whereas H. borelli used the warmer ones. Body size, coloration and geographic distribution may be related to the different patterns observed.
Full Text Available El ciertamente arrogante y algo atrabiliario título de este artículo merece apuntar una lista de obviedades que espero sepan perdonarme. La misma noción de canon, tal y como la entiendo, siguiendo el magistral estudio de Pozuelo Yvancos y Aradra Sánchez (2000, es de por sí compleja y reniega de definiciones simplistas, ya que convergen en ella, entre otras cuestiones, la porosidad social y la inestabilidad que se da en la base, el texto literario. Acotado teóricamente el terreno, las prometidas obviedades. Sé y asumo el riesgo de proponer una serie de novelistas últimos, porque al campo de la novela me limitaré, por lo que tiene de arbitraria injusticia, aunque ésta se vea acotada por el convencimiento razonado. Otros nombres podrían entrar aquí con todo merecimiento (José Ángel González Sáinz, Felipe Benítez Reyes, Javier Cercas, Belén Gopegui, Luis Magrinyà, Antonio Álamo, Antonio Orejudo, Luisa Castro, Cristina Sánchez-Andrade, Benjamín Prado..., y a ellos me dedicaré en próximos trabajos.
Carmen Pozo de la Tijera
Full Text Available Con base en el muestreo de siete localidades y una extensa revisión bibliográfica, se obtuvo la lista de especies de mamíferos terrestres de la Reserva de la Biosfera de Sian Ka’an estado de Quintana Roo, México. Durante 57 días de campo, se utilizaron trampas Sherman, Tomahawk, redes de niebla y escopetas, se registraron rastros y observaciones directas. Se registraron 70 especies, ocho órdenes, 22 familias y 57 géneros. Se encontraron seis especies como nuevos registros: Marmosa mexicana, Micronycteris microtis, Micronycteris schmidtorum, Eptesicus furinalis, Rhogeessa parvula y Ototylomys phyllotis. Doce especies son catalogadas bajo algún riesgo ecológico según la Norma Oficial Mexicana; trece especies son endémicas a Mesoamérica y una endémica de México. Se presentan cuadros de abundancia relativa, registro por localidades y por tipo de vegetación de cada especie.Based on sampling at seven localities and an extensive bibliographic research, we present a species list of terrestrial mammals of the Sian Ka’an Biosphere Reserve, Quintana Roo, Mexico. During 57 days of fieldwork we used Sherman and Tomahawk traps, mist nets, rifles, collected data of trails and made direct observations. We recorded 70 species, eight orders, 22 families, and 57 genera. Six new records are added: Marmosa mexicana, Micronycteris microtis, Micronycteris schmidtorum, Eptesicus furinalis, Rhogeessa parvula, and Ototylomys phyllotis. Twelve species are listed as threatened following the Official Mexican Norm: Tamandua mexicana, Micronycteris brachyotis, Lonchorhina aurita, Alouatta pigra, Ateles geoffroyi, Herpailurus yagouaroundi, Leopardus pardalis, Leopardus wiedii, Panthera onca, Eira barbara, Potos flavus and Tapirus bairdii. Thirteen species are endemic to Mesoamerica: M. mexicana, T. mexicana, Mormoops megalophylla, Tonatia evotis, Bauerus dubiaquercus, A. pigra, A. geoffroyi, T. bairdii, Sciurus deppei, Sciurus yucatanensis, Heteromys gaumeri
Peniche-Lara, Gaspar; Dzul-Rosado, Karla; Pérez-Osorio, Carlos; Zavala-Castro, Jorge
Rickettsia typhi is the causal agent of murine typhus; a worldwide zoonotic and vector-borne infectious disease, commonly associated with the presence of domestic and wild rodents. Human cases of murine typhus in the state of Yucatán are frequent. However, there is no evidence of the presence of Rickettsia typhi in mammals or vectors in Yucatán. The presence of Rickettsia in rodents and their ectoparasites was evaluated in a small municipality of Yucatán using the conventional polymerase chain reaction technique and sequencing. The study only identified the presence of Rickettsia typhi in blood samples obtained from Rattus rattus and it reported, for the first time, the presence of R. felis in the flea Polygenis odiosus collected from Ototylomys phyllotis rodent. Additionally, Rickettsia felis was detected in the ectoparasite Ctenocephalides felis fleas parasitizing the wild rodent Peromyscus yucatanicus. This study's results contributed to a better knowledge of Rickettsia epidemiology in Yucatán.
Full Text Available BACKGROUND: Combining high strength and elasticity, spider silks are exceptionally tough, i.e., able to absorb massive kinetic energy before breaking. Spider silk is therefore a model polymer for development of high performance biomimetic fibers. There are over 41,000 described species of spiders, most spinning multiple types of silk. Thus we have available some 200,000+ unique silks that may cover an amazing breadth of material properties. To date, however, silks from only a few tens of species have been characterized, most chosen haphazardly as model organisms (Nephila or simply from researchers' backyards. Are we limited to 'blindly fishing' in efforts to discover extraordinary silks? Or, could scientists use ecology to predict which species are likely to spin silks exhibiting exceptional performance properties? METHODOLOGY: We examined the biomechanical properties of silk produced by the remarkable Malagasy 'Darwin's bark spider' (Caerostris darwini, which we predicted would produce exceptional silk based upon its amazing web. The spider constructs its giant orb web (up to 2.8 m(2 suspended above streams, rivers, and lakes. It attaches the web to substrates on each riverbank by anchor threads as long as 25 meters. Dragline silk from both Caerostris webs and forcibly pulled silk, exhibits an extraordinary combination of high tensile strength and elasticity previously unknown for spider silk. The toughness of forcibly silked fibers averages 350 MJ/m(3, with some samples reaching 520 MJ/m(3. Thus, C. darwini silk is more than twice tougher than any previously described silk, and over 10 times better than Kevlar®. Caerostris capture spiral silk is similarly exceptionally tough. CONCLUSIONS: Caerostris darwini produces the toughest known biomaterial. We hypothesize that this extraordinary toughness coevolved with the unusual ecology and web architecture of these spiders, decreasing the likelihood of bridgelines breaking and collapsing the web
Full Text Available Methodological reduction is often wrongly identified with ontological reduction. For anyontology has always existential problems of its own which are absent in a methodological approach. Emergence would also be problematic unless it is also contemplated methodologically. As anyphilosophical issue, the question of emergence-reduction is used from a naturalistic stance as aplatform to promote personal ideals of survival. For example, Richard Dawkins would promote aDarwinially reduced world. On the contrary, Richard Lewontin for one would implement a holisticworld essentially Kropotkian. In this context, a contentious term is that of replicator. But this termneed not be either as reductive as Dawkins would have us believe nor as useless as Lewontin thinks.For again evolution by natural selection would always be defended naturalistically along one’s ownideological tenets.
Silvia F. Hernandez Betancourt
Full Text Available Se evaluÃ³ de manera rÃ¡pida y sistemÃ¡tica la riqueza y abundancia relativa de pequeÃ±os roedores en dos agroecosistemas (y un acahual en la Reserva EcolÃ³gica Cuxtal, YucatÃ¡n para obtener un inventario de las especies presentes. Se utilizÃ³ el mÃ©todo de captura â€“ marcaje â€“ recaptura; se marcÃ³ por ectomizaciÃ³n de falanges. Se calculÃ³ la diversidad por el Ãndice de Shannon-Wiener (Hâ€™ y se analizaron edad, proporciÃ³n de sexos y condiciÃ³n reproductiva de las especies mÃ¡s abundantes. Se capturaron un total de 16 individuos de dos familias y siete especies, siendo Mus musculus y Ototylomys phyllotis las especies mÃ¡s abundantes. El Acahual fue el sitio mÃ¡s diverso con cuatro especies (Hâ€™=1.28. Mus musculus fue exclusiva del pastizal. Peromyscus yucatanicus y O. phyllotis se encontraron en pastizal y acahual y Hereromys gaumeri fue exclusiva del acahual. Fue sobresaliente la presencia de H. gaumeri y P. yucatanicus, especies endÃ©micas de la Provincia de la PenÃnsula de YucatÃ¡n. Se presentaron, jÃ³venes, subadultos y adultos en las especies mÃ¡s abundantes, lo mismo que machos y hembras reproductivos, lo cual indica que hay dinÃ¡mica en sus poblaciones. Los agroecosistemas no albergan la biodiversidad original de pequeÃ±os roedores, las especies silvestres pueden ser ocasionales. En contraste pequeÃ±os fragmentos de acahual conservan mayor nÃºmero de especies silvestres como las endÃ©micas que dispersan semillas y hacen posible la regeneraciÃ³n de la selva, por lo tanto se deben conservar.
Comparison of small mammal prevalence of Leishmania (Leishmania mexicana in five foci of cutaneous leishmaniasis in the State of Campeche, Mexico Comparación de las prevalencias de Leishmania (Leishmania mexicana en mamíferos pequeños en cinco focos de leishmaniosis cutánea en el estado de Campeche, México
N.R. Van Wynsberghe
Full Text Available In the Yucatan Peninsula of Mexico, 95% of the human cases of Cutaneous Leishmaniasis are caused by Leishmania (Leishmania mexicana with an incidence rate of 5.08 per 100,000 inhabitants. Transmission is limited to the winter months (November to March. One study on wild rodents has incriminated Ototylomys phyllotis and Peromyscus yucatanicus as primary reservoirs of L. (L. mexicana in the focus of La Libertad, Campeche. In the present study, the prevalence of both infection and disease caused by L. (L. mexicana in small terrestrial mammals were documented during five transmission seasons (1994-2004 in five foci of Leishmaniasis in the state of Campeche. Foci separated by only 100 km, with similar relative abundances of small mammals, were found to differ significantly in their prevalence of both symptoms and infection. Transmission rates and reservoir species seemed to change in space as well as in time which limited the implementation of effective control measures of the disease even in a small endemic area such as the south of the Yucatan Peninsula.En la Península de Yucatán, México, la Leishmaniosis Cutánea es causada por Leishmania (L. mexicana en 95% de los casos humanos, con una incidencia de 5.08% por cada 100,000 habitantes. El ciclo de transmisión se limita a la estación de invierno (noviembre- marzo. Un estudio de mamíferos silvestres incrimina a Ototylomys phyllotis y Peromyscus yucatanicus como reservorios primarios de L. (L. mexicana en el foco de infección de La Libertad, Campeche. En el presente estudio, se documenta la prevalencia de infección/enfermedad causada por L. (L. mexicana en pequeños mamíferos, durante cinco estaciones de transmisión (1994-2004 en cinco focos de CL del estado de Campeche. Los focos separados por solamente 100 km. de distancia, aún cuando tienen abundancias relativas de pequeños roedores similares, fueron significativamente diferentes en relación a la prevalencia de síntomas así como de
Holmgren, C.A.; Betancourt, J.L.; Rylander, K.A.; Roque, J.; Tovar, O.; Zeballos, H.; Linares, E.; Quade, Jay
Rodent (Abrocoma, Lagidium, Phyllotis) middens collected from 2350 to 2750 m elevation near Arequipa, Peru (16??S), provide an ???9600-yr vegetation history of the northern Atacama Desert, based on identification of >50 species of plant macrofossils. These midden floras show considerable stability throughout the Holocene, with slightly more mesophytic plant assemblages in the middle Holocene. Unlike the southwestern United States, rodent middens of mid-Holocene age are common. In the Arequipa area, the midden record does not reflect any effects of a mid-Holocene mega drought proposed from the extreme lowstand (100 m below modern levels, >6000 to 3500 yr B.P.) of Lake Titicaca, only 200 km east of Arequipa. This is perhaps not surprising, given other evidence for wetter summers on the Pacific slope of the Andes during the middle Holocene as well as the poor correlation of summer rainfall among modern weather stations in the central AndesAtacama Desert. The apparent difference in paleoclimatic reconstructions suggests that it is premature to relate changes observed during the Holocene to changes in El Nin??o Southern Oscillation modes. ?? 2001 University of Washington.
Full Text Available Rickettsia typhi is the causal agent of murine typhus; a worldwide zoonotic and vector-borne infectious disease, commonly associated with the presence of domestic and wild rodents. Human cases of murine typhus in the state of Yucatán are frequent. However, there is no evidence of the presence of Rickettsia typhi in mammals or vectors in Yucatán. The presence of Rickettsia in rodents and their ectoparasites was evaluated in a small municipality of Yucatán using the conventional polymerase chain reaction technique and sequencing. The study only identified the presence of Rickettsia typhi in blood samples obtained from Rattus rattus and it reported, for the first time, the presence of R. felis in the flea Polygenis odiosus collected from Ototylomys phyllotis rodent. Additionally, Rickettsia felis was detected in the ectoparasite Ctenocephalides felis fleas parasitizing the wild rodent Peromyscus yucatanicus. This study’s results contributed to a better knowledge of Rickettsia epidemiology in Yucatán.
Van Wynsberghe, N R; Canto-Lara, S B; Sosa-Bibiano, E I; Rivero-Cárdenas, N A; Andrade-Narváez, F J
In the Yucatan Peninsula of Mexico, 95% of the human cases of Cutaneous Leishmaniasis are caused by Leishmania (Leishmania) mexicana with an incidence rate of 5.08 per 100,000 inhabitants. Transmission is limited to the winter months (November to March). One study on wild rodents has incriminated Ototylomys phyllotis and Peromyscus yucatanicus as primary reservoirs of L. (L.) mexicana in the focus of La Libertad, Campeche. In the present study, the prevalence of both infection and disease caused by L. (L.) mexicana in small terrestrial mammals were documented during five transmission seasons (1994-2004) in five foci of Leishmaniasis in the state of Campeche. Foci separated by only 100 km, with similar relative abundances of small mammals, were found to differ significantly in their prevalence of both symptoms and infection. Transmission rates and reservoir species seemed to change in space as well as in time which limited the implementation of effective control measures of the disease even in a small endemic area such as the south of the Yucatan Peninsula.
Polgar, G; Sacchetti, A; Galli, P
During several surveys made in the region of the lower Fly River and delta, Papua New Guinea, nine species of oxudercine gobies (Gobiidae: Oxudercinae) were recorded: Boleophthalmus caeruleomaculatus, Oxuderces wirzi, Periophthalmodon freycineti, Periophthalmus darwini, Periophthalmus novaeguineaensis, Periophthalmus takita, Periophthalmus weberi, Scartelaos histophorus and Zappa confluentus. An exploratory multivariate analysis of their habitat conditions discriminated five guilds, differentially distributed in habitats with different quantities of environmental water and three guilds corresponding to different levels of salinity. A partial correspondence between phylogenetic and ecological categories suggested the presence of parallel adaptive radiations within different genera. In particular, the species found in the most terrestrial habitats (P. weberi) was also found in the widest range of conditions, suggesting that colonization of extreme semi-terrestrial and freshwater habitats by this species was facilitated by eurytypy. It is proposed that these findings provide insight into convergent adaptations for the vertebrate eco-evolutionary transition from sea to land. © 2010 The Authors. Journal of Fish Biology © 2010 The Fisheries Society of the British Isles.
Torres-Carvajal, Omar; Rodríguez-Guerra, Andrea; Chaves, Jaime A
We re-examined the biogeography of the leaf-toed geckos (Phyllodactylus) endemic to the Galápagos Islands by analyzing for the first time samples of P. gilberti, a species endemic to Wolf island, in a phylogenetic framework. Our aim was to test the three-colonizations scenario previously proposed for these lizards and estimate the age of each colonization event. To achieve this we estimated simultaneously a species tree and divergence times with Bayesian methods. Our results supported the three-colonizations scenario. Similar to a previous hypothesis, the species tree obtained here showed that most species of Phyllodactylus are nested in a single clade with an age between 5.49 and 13.8Ma, whereas a second independent colonization corresponding to P. darwini from San Cristóbal island occurred 3.03Ma ago. The species from Wolf island, P. gilberti, stems from a more recent colonization event (0.69Ma). Thus, present diversity of Galápagos leaf-toed geckos stems from three independent, asynchronous colonization events. As with other Galápagos organisms, the Pacific coast of South America seems to be the source for the founders of P. gilberti. Copyright © 2016 Elsevier Inc. All rights reserved.
Full Text Available Recent research has confirmed the presence of several species of undescribed macrocnemic zoanthids (Cnidaria: Hexacorallia: Zoantharia: Macrocnemina in the Galapagos. In this study four new species, including two belonging to a new genus, are described. Two species, Terrazoanthus onoi sp. n. and Terrazoanthus sinnigeri sp. n., both belong within the recently erected family Hydrozoanthidae to the new genus Terrazoanthus, which can be distinguished from the type genus Hydrozoanthus by being attached to abiotic substrate as opposed to hydrozoans for Hydrozoanthus. Each new species of zoanthid can be clearly distinguished by a number of characters. Antipathozoanthus hickmani sp. n. is distinguished by its exclusive association with the antipatharian Antipathes galapagensis, and has approximately 40 tentacles. Parazoanthus darwini sp. n. is distinguished by its frequent association with sponges, with approximately 24–30 tentacles and polyps embedded in a well-developed coenenchyme. T. onoi sp. n. is distinguished by its bright red oral disk color, 32–40 tentacles, and has only basitrichs and mastigophores present in the pharynx. T. sinnigeri sp. n. is distinguished by usually occurring on the underside of rubble and rocks on sandy bottoms, showing 30–36 tentacles, and numerous nematocyst types in the pharynx. The two Terrazoanthus species, although divergent in both morphology and ecology, are apparently very closely related, with identical mitochondrial 16S ribosomal DNA and cytochrome oxidase subunit I sequences. These two species can be molecularly distinguished by their subtly different yet distinct sequences of internal transcribed spacer of ribosomal DNA (ITS-rDNA.
Ortiz, P. E.
Full Text Available A micromammal archaeological sequence (2120 f 120 to 780 f 100 years BP from Inca Cueva 5 site (23" 05' S - 65" 27' W; 3700 m.a.s.l., Jujuy Province, Argentina was studied. The following mammalian taxa were recorded: Order Didelphimorphia, Family Didelphidae, Thylamys cf. T. pallidior; Order Rodentia, Family Muridae, Akodon cf. A. albiventer, Andinomys edax, Auliscomys sublimis, Calomys lepidus, Neotomys ebriosus, Phyllotis sp.; Family Caviidae, Cavia cf. C. tschudii, Galea musteloides; Family Abrocomidae, Abrocoma cinerea; Family Chinchillidae, Lagidium viscacia; Family Octodontidae, Octodontomys gliroides. The taphonomy indicates that the sequence is an owl pellet accumulation inside the cave. The general landscape corresponds to the oriental border of the Puna steppe, with scattered shrub and low brush vegetation. Near the site there are small tree groups of Polylepis australis as well as small streams covered with grass and ciperaceous vegetation known as Â«vegasÂ». Al1 the recorded taxa at Inca Cueva 5 exist today in Puna and Prepuna environments from Jujuy and Salta Provinces and southem Bolivia, excepting Cavia cf. C. tschudii. The modem records of this species in northem Argentina and southern Bolivia come from localities with high montane bunchgrass prairies and forests of the humid Yungas phytogeographical region. The presence of this species in the sequence suggests wetter climatic conditions on this region when the archaeological site was originated. Later drier conditions, caused probably by anthropic influence in the last 500 years, produced the retraction of Cavia tschudii to the moist eastern side of the Andes and its disappeareance of the Puna areas.El sitio arqueológico Inca Cueva 5 se encuentra en la provincia de Jujuy, Argentina, en el borde oriental de la región de la Puna (23" 05' S - 65" 27' W; 3700 m s n m y está fechado entre 2120 f 120 y 780 f 100 años radiocarbónicos AP. El estudio de una pequeña muestra de
Hashiguchi, Yoshihisa; Gomez L, Eduardo A; Cáceres, Abraham G; Velez, Lenin N; Villegas, Nancy V; Hashiguchi, Kazue; Mimori, Tatsuyuki; Uezato, Hiroshi; Kato, Hirotomo
The vector Lutzomyia sand flies and reservoir host mammals of the Leishmania parasites, causing the Andean cutaneous leishmaniasis (Andean-CL, uta) in Peru and Ecuador were thoroughly reviewed, performing a survey of literatures including our unpublished data. The Peruvian L. (V.) peruviana, a principal Leishmania species causing Andean-CL in Peru, possessed three Lutzomyia species, Lu. peruensis, Lu. verrucarum and Lu. ayacuchensis as vectors, while the Ecuadorian L. (L.) mexicana parasite possessed only one species Lu. ayacuchensis as the vector. Among these, the Ecuadorian showed a markedly higher rate of natural Leishmania infections. However, the monthly and diurnal biting activities were mostly similar among these vector species was in both countries, and the higher rates of infection (transmission) reported, corresponded to sand fly's higher monthly-activity season (rainy season). The Lu. tejadai sand fly participated as a vector of a hybrid parasite of L. (V.) braziliensis/L. (V.) peruviana in the Peruvian Andes. Dogs were considered to be principal reservoir hosts of the L. (V.) peruviana and L. (L.) mexicana parasites in both countries, followed by other sylvatic mammals such as Phyllotis andium, Didelphis albiventris and Akodon sp. in Peru, and Rattus rattus in Ecuador, but information on the reservoir hosts/mammals was extremely poor in both countries. Thus, the Peruvian disease form demonstrated more complicated transmission dynamics than the Ecuadorian. A brief review was also given to the control of vector and reservoirs in the Andes areas. Such information is crucial for future development of the control strategies of the disease. Copyright © 2017 Elsevier B.V. All rights reserved.
Ibargüengoytía, Nora R.
Full Text Available Existe la creencia popular de que los lagartos del género Diplolaemus (Leiosauridae de Patagonia, Argentina, son capaces de conferir mordeduras venenosas que pueden causar inflamación e incluso la muerte de animales de granja o salvajes. No obstante, no existe evidencia de la existencia de glándulas de veneno en estos lagartos. La inflamación y absceso provocado como resultado de las heridas de mordedura podría ser causado por agentes infecciosos. Este es el primer estudio acerca de la microbiota oral de los lagartos del género Diplolaemus de Argentina. Para este trabajo se analizó un espécimen de D. darwini y tres individuos de Diplolaemus "forma alto patagonica". Las muestras de hisopados de boca de los lagartos fueron incubados aeróbica y anaeróbicamente, algunos de ellos fueron subcultivados en agar de sangre ovina al 5% e incubados nuevamente. Todas las colonias representativas observadas fueron subcultivadas para su purificación y sujetas a tests bioquímicos. La bacteria Clostridium perfigrens fue determinada por medio de la técnica de reacción en cadena de la Polimerasa. Se identificaron cuatro especies de bacterias: Staphylococus warneri, Clostridium bifermentans, Clostridium perfringens y Stomatococcus muscilaginosus. Estas especies son conocidas como agentes etiológicos de numerosas infecciones de humanos y animales. Si bien estas bacterias representan sólo un pequeño número de las posibles bacterias aisladas de la cavidad oral de Diplolaemus, están indicando la presencia de patógenos humanos y animales. Lizards of genus Diplolaemus (Leiosauridae from Patagonia, Argentina are believed to have "poisonous" bites that can cause inflammation and death of farm and wild animals. However there is no evidence of poisonous glands in these lizards. It is proposed that the inflammation and abscesses resulting from these bite wounds are caused by infectious agent(s. This is the first study of the oral microbiota of Diplolaemus
Bargo, M Susana; Toledo, Néstor; Vizcaíno, Sergio F
Sloths are among the most characteristic elements of the Cainozoic of South America and are represented, during the Pleistocene, by approximately nine genera of gigantic ground sloths (Megatheriidae and Mylodontidae). A few contributions have described their masticatory apparatus, but almost no attention has been paid to the reconstruction of the muzzle, an important feature to consider in relation to food intake, and particularly relevant in sloths because of the edentulous nature of the muzzle and its varied morphology. The relationship between dietary habits and shape and width of the muzzle is well documented in living herbivores and has been considered an important feature for the inference of alimentary styles in fossils, providing an interesting methodological tool that deserves to be considered for xenarthrans. The goal of this study was to examine models of food intake by reconstructing the appearance and shape of the muzzle in five species of Pleistocene ground sloths (Megatherium americanum, Glossotherium robustum, Lestodon armatus, Mylodon darwini, and Scelidotherium leptocephalum) using reconstructions of the nasal cartilages and facial muscles involved in food intake. The preservation of the nasal septum, and the scars for muscular attachment in the rostral part of the skulls, allow making a conservative reconstruction of muzzle anatomy in fossil sloths. Wide-muzzled ground sloths (Glossotherium and Lestodon) had a square, nonprehensile upper lip and were mostly bulk-feeders. The lips, coupled with the tongue, were used to pull out grass and herbaceous plants. Narrow-muzzled sloths (Mylodon, Scelidotherium, and Megatherium) had a cone-shaped and prehensile lip and were mixed or selective feeders. The prehensile lip was used to select particular plants or plant parts. (c) 2005 Wiley-Liss, Inc.
Full Text Available This paper deals with a definition of the lower boundary stratotype of the Tithonian Stage in the Upper Jurassic succession of Monte Inici, Western Sicily. The upper member of the Rosso Ammonitico Fm. is 27 m thick and shows a typical nodular-calcareous lithofacies; its lower beds have been sampled for biostratigraphic and paleomagnetic purposes. Though the succession is affected by high stratigraphic condensation, the resulting hiatuses have been shown to be below biochronological resolution and thus do not hinder any biostratigraphic definition. The biostratigraphic analysis has been based on the rich ammonite assemblages in which the common genus Hybonoticeras is the index-key for characterizing the Kimmeridgian-Tithonian boundary. Four ammonite biozones have been identified; the basal Tithonian one is defined by the assemblage of Hybonoticeras gr. hybonotum and Haploceras staszycii. The recorded calcareous nannofossil bioevents allow recognition of the V. stradneri and C. mexicana Zones, whose boundary is located a little below the identified Tithonian lower boundary. The paleomagnetic record shows normal polarity in the S. darwini/V. albertinum Zone and mainly reverse polarity in the H. beckeri and H. hybonotum Zones, with three minor normal polarity intervals; the lower boundary of the Tithonian falls in the oldest of these intervals. The integrated multidisciplinary stratigraphic information gathered from the Contrada Fornazzo section defines the lower boundary of the H. hybonotum Zone at the base of Bed 110, and supplies elements of chrono-correlation sufficient to regard this section as a possible G.S.S.P. of the Tithonian Stage.
Full Text Available Despite the alarming rates of deforestation and forest fragmentation, Madagascar still harbors extraordinary biodiversity. However, in many arthropod groups, such as spiders, this biodiversity remains mostly unexplored and undescribed. The first subsocial Madagascan species of the theridiid spider genus Anelosimus were described in 2005 when six new species were found to coexist in the Périnet forest fragment within Andasibe-Mantadia NP. However, this discovery was based only on a few specimens and the extent of this Madagascan radiation has remained unknown. We here report on a thorough survey of >350 colonies from Périnet, and three pilot surveys into additional Madagascar forests (Ambohitantely, Ranamofana, and Montagne d’Ambre. The morphological, molecular and natural history data from these surveys facilitated a revised taxonomy and phylogenetic hypothesis of Madagascan Anelosimus. This subsocial clade currently comprises six previously known (A. andasibe Agnarsson & Kuntner, 2005, A. may Agnarsson, 2005, A. nazariani Agnarsson & Kuntner, 2005, A. sallee Agnarsson & Kuntner, 2005, A. salut Agnarsson & Kuntner, 2005, A. vondrona Agnarsson & Kuntner, 2005 and 10 new species: A. ata sp. n., A. buffoni sp. n., A. darwini sp. n., A. hookeri sp. n., A. huxleyi sp. n., A. lamarcki sp. n., A. moramora sp. n., A. tita sp. n., A. torfi sp. n., A. wallacei sp. n.. With the exception of A. may and A. vondrona, all other species appear to be single forest endemics. While additional sampling is necessary, these data imply a much higher local richness and endemism in Madagascan forests than in any other comparable area globally. The phylogenetic results establish a sister clade relationship between the subsocial Anelosimus in Madagascar and the American ‘eximius group’, and between the solitary A. decaryi on Madagascar and a solitary American clade. These findings imply duplicate colonizations from America, an otherwise rare biogeographical
The Eocene (∾48 Ma) Messel Pit in Germany is a UNESCO World Heritage Site because of its exceptionally preserved fossils, including vertebrates, invertebrates, and plants. Messel fossil vertebrates are typically characterized by their articulated state, and in some cases the skin, hair, feathers, scales and stomach contents are also preserved. Despite the exceptional macroscopic preservation of Messel fossil vertebrates, the microstructural aspect of these fossils has been poorly explored. In particular, soft tissue structures such as hair or feathers have not been chemically analyzed, nor have bone microstructures. I report here the preservation and recovery of osteocyte-like and blood vessel-like microstructures from the bone of Messel Pit specimens, including the turtles Allaeochelys crassesculpta and Neochelys franzeni, the crocodile Diplocynodon darwini, and the pangolin Eomanis krebsi. I used a Field Emission Scanning Electron Microscope (FESEM) and a Phenom ProX desktop scanning electron microscope (LOT-QuantumDesign) equipped with a thermionic CeB6 source and a high sensitivity multi-mode backscatter electron (BSE) for microscopical and elemental characterization of these bone microstructures. Osteocyte-like and blood vessel-like microstructures are constituted by a thin layer (∾50 nm thickness), external and internal mottled texture with slightly marked striations. Circular to linear marks are common on the external surface of the osteocyte-like microstructures and are interpreted as microbial troughs. Iron (Fe) is the most abundant element found in the osteocyte-like and blood vessel-like microstructures, but not in the bone matrix or collagen fibril-like microstructures. The occurrence of well-preserved soft-tissue elements (at least their physical form) establishes a promising background for future studies on preservation of biomolecules (proteins or DNA) in Messel Pit fossils.
Full Text Available The Eocene (∾48 Ma Messel Pit in Germany is a UNESCO World Heritage Site because of its exceptionally preserved fossils, including vertebrates, invertebrates, and plants. Messel fossil vertebrates are typically characterized by their articulated state, and in some cases the skin, hair, feathers, scales and stomach contents are also preserved. Despite the exceptional macroscopic preservation of Messel fossil vertebrates, the microstructural aspect of these fossils has been poorly explored. In particular, soft tissue structures such as hair or feathers have not been chemically analyzed, nor have bone microstructures. I report here the preservation and recovery of osteocyte-like and blood vessel-like microstructures from the bone of Messel Pit specimens, including the turtles Allaeochelys crassesculpta and Neochelys franzeni, the crocodile Diplocynodon darwini, and the pangolin Eomanis krebsi. I used a Field Emission Scanning Electron Microscope (FESEM and a Phenom ProX desktop scanning electron microscope (LOT-QuantumDesign equipped with a thermionic CeB6 source and a high sensitivity multi-mode backscatter electron (BSE for microscopical and elemental characterization of these bone microstructures. Osteocyte-like and blood vessel-like microstructures are constituted by a thin layer (∾50 nm thickness, external and internal mottled texture with slightly marked striations. Circular to linear marks are common on the external surface of the osteocyte-like microstructures and are interpreted as microbial troughs. Iron (Fe is the most abundant element found in the osteocyte-like and blood vessel-like microstructures, but not in the bone matrix or collagen fibril-like microstructures. The occurrence of well-preserved soft-tissue elements (at least their physical form establishes a promising background for future studies on preservation of biomolecules (proteins or DNA in Messel Pit fossils.
Julio L. Betancourt
Full Text Available Las zonas áridas y semiáridas de Sudamérica carecen de registros históricos exhaustivos de vegetación y clima, a pesar de la utilidad que ellos representan para el establecimiento de condiciones basales y tasas naturales de variabilidad en procesos abióticos y bióticos. Fuentes comúnmente utilizadas en el estudio de paleovegetación como el polen, son escasas en zonas áridas y semiáridas en Sudamérica, lo que se refleja en el limitado número de estudios vegetacionales durante el Cuaternario Tardío. El vacío existente en el conocimiento de la historia vegetacional de esta zona podría ser remediado gracias al descubrimiento y análisis de paleomadrigueras de roedores en ambientes rocosos. Estos depósitos, producidos por roedores de los géneros Lagidium, Phyllotis, Abrocoma y Octodontomys y posiblemente otros, son ricos en restos vegetales como ramas, hojas, polen o cutículas; y restos animales como fecas, huesos o insectos. Las paleomadrigueras de roedores han sido extensamente utilizadas en el estudio de zonas áridas en Norteamérica, donde más de 2.500 registros producidos por roedores del género Neotoma han sido analizadas desde 1960, permitiendo reconstruir una detallada historia de cambios vegetacionales y climáticos de los últimos 40.000 años en el suroeste de Norteamérica. Investigaciones recientes han revelado la presencia de paleomadrigueras en la pre-puna, los desiertos del Monte y Patagonia del oeste argentino, el desierto de Atacama al norte de Chile y sur del Perú, el matorral Mediterráneo de Chile central, y la Puna del Altiplano Andino. Estos hallazgos fortalecen el gran potencial que dichos depósitos tienen para reconstruir la vegetación y el clima en Sudamérica. Con el fin de aportar elementos para la detección, uso y análisis de paleomadrigueras de roedores, entregamos una síntesis de los depósitos registrados hasta la fecha en Sudamérica, así como una descripción de sus probables agentes
Full Text Available The genera Odontacolus Kieffer and Cyphacolus Priesner are among the most distinctive platygastroid wasps because of their laterally compressed metasomal horn; however, their generic status has remained unclear. We present a morphological phylogenetic analysis comprising all 38 Old World and four Neotropical Odontacolus species and 13 Cyphacolus species, which demonstrates that the latter is monophyletic but nested within a somewhat poorly resolved Odontacolus. Based on these results Cyphacolus syn. n. is placed as a junior synonym of Odontacolus which is here redefined. The taxonomy of Old World Odontacolus s.str. is revised; the previously known species O. longiceps Kieffer (Seychelles, O. markadicus Veenakumari (India, O. spinosus (Dodd (Australia and O. hackeri (Dodd (Australia are re-described, and 32 new species are described: O. africanus Valerio & Austin sp. n. (Congo, Guinea, Kenya, Madagascar, Mozambique, South Africa, Uganda, Zimbabwe, O. aldrovandii Valerio & Austin sp. n. (Nepal, O. anningae Valerio & Austin sp. n. (Cameroon, O. australiensis Valerio & Austin sp. n. (Australia, O. baeri Valerio & Austin sp. n. (Australia, O. berryae Valerio & Austin sp. n. (Australia, New Zealand, Norfolk Island, O. bosei Valerio & Austin sp. n. (India, Malaysia, Sri Lanka, O. cardaleae Valerio & Austin sp. n. (Australia, O. darwini Valerio & Austin sp. n. (Thailand, O. dayi Valerio & Austin sp. n. (Indonesia, O. gallowayi Valerio & Austin sp. n. (Australia, O. gentingensis Valerio & Austin sp. n. (Malaysia, O. guineensis Valerio & Austin sp. n. (Guinea, O. harveyi Valerio & Austin sp. n. (Australia, O. heratyi Valerio & Austin sp. n. (Fiji, O. heydoni Valerio & Austin sp. n. (Malaysia, Thailand, O. irwini Valerio & Austin sp. n. (Fiji, O. jacksonae Valerio & Austin sp. n. (Cameroon, Guinea, Madagascar, O. kiau Valerio & Austin sp. n. (Papua New Guinea, O. lamarcki Valerio & Austin sp. n. (Thailand, O. madagascarensis Valerio & Austin sp. n
Full Text Available Los lagartos del género Liolaemus se distribuyen desde las altas cordilleras de Perú y Bolivia en el norte hasta el extremo austral de América del Sur. Se analizan los cariotipos descriptos para las 55 especies de Liolaemus con análisis citogenético reportado, que están incluidos en la clasificación de Etheridge (1995, como grupos chiliensis, signifer, montanus, boulengeri y wiegmanni. Los objetivos de este trabajo fueron: (1 analizar y comparar la composición citogenética de las mismas, (2 revalorizar la participación de la citogenética en la resolución de confusiones taxonómicas dentro del género, (3 obtener caracteres citogenéticos para análisis filo- genéticos, (4 plantear inferencias sobre su evolución cromosómica y pautas apropiadas para el trabajo citogenético en el género. La configuración cromosómica diploide varía desde 2n= 28 para L. uspallatensis a 2n= 44 para L. monticola monticola, comúnmente formada por 6 pares de macrocromosomas de morfología metacéntrica o submetacéntrica y 16 a 32 microcromosomas. El estudio de las figuras meióticas en especies con microcromosomas es aconsejable porque permite definir con mayor certeza el número diploide. La revisión de las publicaciones pone de manifiesto que las bandas C no son informativas para este género. Se analizan ejemplos sobre los aportes de la caracterización citogenética de las especies a la diagnosis, como el «complejo darwini», especies del grupo chiliensis y casos de simpatría. Se propone para el género Liolaemus, una serie de doce caracteres citogenéticos para ser incorporados a futuros estudios filogenéticos. En el grupo boulengeri el aumento de microcromosomas por fisiones céntricas sería la principal característica en la evolución cromosómica del grupo. Se advierte que el conocimiento acabado de cada especie y las relaciones entre las especies del género no es sencillo y sólo será posible con el trabajo interdisciplinario de tax
Jamali, H.; Livesely, S. J.; Arndt, S. K.; Dawes-Gromadzki, T.; Cook, G. D.; Hutley, L.
Termites are estimated to contribute 3-19% to the global methane emissions. These estimates have large uncertainties because of the limited number of field-based studies and species studied, as well as issues of diel and seasonal variation. We measured methane fluxes from four common mound-building termite species (Microcerotermes nervosus, n=26; M. serratus, n=4; Tumulitermes pastinator, n=5; and Amitermes darwini, n=4) in tropical savannas near Darwin in the Northern Territory, Australia. Methane fluxes from replicated termite mounds were measured in the field using manual chambers with fluxes reported on a mound volume basis. Methane flux was measured in both wet and dry seasons and diel variation was investigated by measuring methane flux every 4 hours over a 24 hour period. Mound temperature was measured concurrently with flux to examine this relationship. In addition, five M. nervosus mounds removed from the field and incubated under controlled temperature conditions over a 24 hour period to remove the effect of varying temperature. During the observation campaigns, mean monthly minimum and maximum temperatures for February (wet season) were 24.7 and 30.8°C, respectively, and were 20.1 to 31.4 °C in June (dry season). Annual rainfall in 2008 for Darwin was 1970.1 mm, with a maximum of 670 mm falling in February and no rain in May and June. Methane fluxes were greatest in the wet season for all species, ranging from 265.1±101.1 (T. pastinator) to 2256.6±757.1 (M. serratus) µg CH4-C/m3/h. In the dry season, methane fluxes were at their lowest, ranging from 10.0±5.5 (T. pastinator) to 338.0±165.9 (M. serratus) µg CH4-C/m3/h. On a diel basis, methane fluxes were smallest at the coolest time of the day (~0700 hrs) and greatest at the warmest (~1400 hrs) for all species, and for both wet and dry seasons. Typical diel variation in flux from M. serratus dominated mounds ranged from 902.6±261.9 to 1392.1±408.1 µg CH4-C/m3/h in wet season and 99.6±57.4 to
Lejeune P. H. de Oliveira
regime is Ceratiumplancton. POLYHALINE WATER REGIMB — Water almost sea water, but directly influenced by continental lands, with rock salts dissolved and in suspension. Salinity: 33 to 32/1.000. This waters endure the actions of the popular nicknamed «water of the hill» (as the waters of mesohaline and oligohaline regimes, becoming suddenly reddish during several hours. That pheno¬menon returns several times in the year and come with great mortality of fishes. In these waters, according to Dr. J. G. FARIA there are species of Protozoa : Peridinea, the Glenoidinium trochoideum St., followed by its satellites which he thinks that they are able to secret toxical substances which can slaughter some species of fishes. In these «waters of the hill» was found a species of Copepoda the Charlesia darwini. In August 1946 the west shore of the Guanabara was plenty of killed fishes occupying a area of 8 feet large by 3 nautical miles of lenght. The enclosure for catching fishes in the rivers mouthes presents in these periods mass dead fishes. The phenomenon of «waters of the hill» appears with the first rains after a period of long dryness. MESOHALINE WATER REGIME — Fig. 4 shows the the diagramm scheme. Salt or brackish water from 30 to 17/1.000 salinity, sometimes until 10/1.000. Turbid waters with mud in suspension, chestnut, claveyous waters; shore dirty black mud without waving bursting; the waters are warmer and shorner than those of the polihaline regime. Mangrove shore with the mangrove trees : Rhizophora mangle L., Avicennia sp., Laguncularia sp., and the »cotton tree of sea» Hibiscus sp. Fauna: the great land crab «guaimú» Cardisoma guanhumi Latr., ashore in dry firm land. There is the real land crab Ucides cordatus (L. in wetting mud and in neigh¬ bourhood of the burrows of the fiddler-crabs of genus Uca. On stones and in the roots of the Rhizophora inhabits the brightly colored mangrove-tree-crab («aratu» Portuguese nickname Goniopsis cruentata