Full Text Available Abstract Background Comparative analyses between amphibians, concentrating on the cellular mechanisms of morphogenesis, reveal a large variability in the early developmental processes that were thought to be conserved during evolution. Increased egg size is one factor that could have a strong effect on early developmental processes such as cleavage pattern and gastrulation. Salamanders of the family Plethodontidae are particularly appropriate for such comparative studies because the species have eggs of varying size, including very large yolky eggs. Results In this paper, we describe for the first time the early development (from fertilization through neurulation of the plethodontid salamander Ensatina eschscholtzii. This species has one of the largest eggs known for an amphibian, with a mean ± SD diameter of 6 ± 0.43 mm (range 5.3-6.9; n = 17 eggs. Cleavage is meroblastic until approximately the 16-cell stage (fourth or fifth cleavage. At the beginning of gastrulation, the blastocoel roof is one cell thick, and the dorsal lip of the blastopore forms below the equator of the embryo. The ventral lip of the blastopore forms closer to the vegetal pole, and relatively little involution occurs during gastrulation. Cell migration is visible through the transparent blastocoel roof of the gastrula. At the end of gastrulation, a small archenteron spreading dorsally from the blastopore represents the relatively small and superficial area of the egg where early embryonic axis formation occurs. The resulting pattern is similar to the embryonic disk described for one species of anuran. Conclusions Comparisons with the early development of other species of amphibians suggest that an evolutionary increase in egg size can result in predictable changes in the patterns and rate of early development, but mainly within an evolutionary lineage.
Wake, Thomas A.; Roeder, Mark A.
Analysis of late Pleistocene fossils recovered from near the Huntington Beach, California (USA), pier (site LACM 7679) has revealed a diverse fauna dating to approximately 40 14C ka BP. Extinct megafauna (three genera) are present; however, a microfauna including three genera of fish, five genera of amphibians, twelve genera of reptiles, two genera of birds, and ten genera of small mammals dominates the assemblage in terms of diversity. Additional identification of seven genera of non-marine mollusks and various macro- and microscopic plant remains including grasses, three families of herbs, and seven genera of trees provides a wealth of information concerning the past ecology of what is currently a coastal dune field complex. During the Rancholabrean Period, the LACM 7679 locality was approximately 10 km inland from the Pleistocene coastline and contained lush riparian zones interspersed with coastal sage scrub, a few trees, and grasslands teeming with a variety of small and large animals.
Alexandrino, Joao; Baird, Stuart J.E.; Lawson, Lucinda; Macey, J. Robert; Moritz, Craig; Wake, David B.
The analysis of interactions between lineages at varying levels of genetic divergence can provide insights into the process of speciation through the accumulation of incompatible mutations. Ring species, and especially the Ensatina eschscholtzii system exemplify this approach. The plethodontid salamanders Ensatina eschscholtzii xanthoptica and Ensatina eschscholtzii platensis hybridize in the Central Sierran foothills of California. We compared the genetic structure across two transects (southern and northern Calaveras Co.), one of which was re-sampled over 20 years, and examined diagnostic molecular markers (eight allozyme loci and mitochondrial DNA) and a diagnostic quantitative trait (color pattern). Key results across all studies were: (i) cline centers for all markers were coincident and the zones were narrow, with width estimates of 730m to 2000m; (ii) cline centers at the northern Calaveras transect were coincident between 1981 and 2001, demonstrating repeatability over 5 generations; (iii) there are very few if any putative F1's, but a relatively high number of backcrossed individuals (57-86 percent) in the central portion of transects; (iv) we found substantial linkage disequilibrium in all three studies and strong heterozygote deficit both in northern Calaveras, in 2001, and southern Calaveras. Both linkage disequilibrium and heterozygote deficit show maximum values near the center of the zones (R and Fis, approx. equal to 0.5). Using estimates of cline width and dispersal, we infer strong selection against hybrids (s* approx. equal to 46-75 percent). This is sufficient to promote accumulation of differences at loci that are neutral or under divergent selection, but would still allow for introgression of adaptive alleles. The evidence for strong, but incomplete isolation across this centrally located contact is consistent with theory suggesting a gradual increase in postzygotic incompatibility between allopatric populations subject to divergent
Kee Peng Ng
Full Text Available Background Daldinia eschscholtzii is a filamentous wood-inhabiting endophyte commonly found in woody plants. Here, we report the identification and characterization of nine D. eschscholtzii isolates from skin scrapings, nail clippings, and blood. Methods The nine isolates were identified based on colony morphology, light microscopy, and internal transcribed spacer (ITS-based phylogeny. In vitro antifungal susceptibility of the fungal isolates was evaluated by the Etest to determine the minimum inhibitory concentration (MIC. Results The nine isolates examined were confirmed as D. eschscholtzii. They exhibited typical features of Daldinia sp. on Sabouraud Dextrose Agar, with white felty colonies and black-gray coloration on the reverse side. Septate hyphae, branching conidiophore with conidiogenous cells budding from its terminus, and nodulisporium-like conidiophores were observed under the microscope. Phylogenetic analysis revealed that the nine isolates were clustered within the D. eschscholtzii species complex. All the isolates exhibited low MICs against azole agents (voriconazole, posaconazole, itraconazole, and ketoconazole, as well as amphotericin B, with MIC of less than 1 µg/ml. Discussion Early and definitive identification of D. eschscholtzii is vital to reducing misuse of antimicrobial agents. Detailed morphological and molecular characterization as well as antifungal profiling of D. eschscholtzii provide the basis for future studies on its biology, pathogenicity, and medicinal potential.
Full Text Available ( FJ151945 |pid:none) Ensatina eschscholtzii xanthoptica... 34 7.6 FJ151867_1( FJ151867 |pid:none) Ensatina eschscholtzii xanthoptica... 9.9 FJ151878_1( FJ151878 |pid:none) Ensatina eschscholtzii xanthoptica... 33 9.9 FJ151848_1( FJ151848 |pid:...none) Ensatina eschscholtzii xanthoptica... 33 9.9 FJ151923_1( FJ151923 |pid:none...) Ensatina eschscholtzii xanthoptica... 33 9.9 protein update 2009. 6.12 PSORT psg: 0.85 gvh: 0.37 alm: 0.33
Alicia K. Bird
Full Text Available A multitude of microorganisms live on and within plant and animal hosts, yet the ecology and evolution of these microbial communities remains poorly understood in many taxa. This study examined the extent to which environmental factors and host taxonomic identity explain microbiome variation within two salamander genera, Ensatina and Batrachoseps, in the family Plethodontidae. In particular, we assessed whether microbiome differentiation paralleled host genetic distance at three levels of taxonomy: genus and high and low clade levels within Ensatina eschscholtzii. We predicted that more genetically related host populations would have more similar microbiomes than more distantly related host populations. We found that salamander microbiomes possess bacterial species that are most likely acquired from their surrounding soil environment, but the relative representation of those bacterial species is significantly different on the skin of salamanders compared to soil. We found differences in skin microbiome alpha diversity among Ensatina higher and lower clade groups, as well as differences between Ensatina and Batrachoseps. We also found that relative microbiome composition (beta diversity did vary between Ensatina lower clades, but differences were driven by only a few clades and not correlated to clade genetic distances. We conclude this difference was likely a result of Ensatina lower clades being associated with geographic location and habitat type, as salamander identity at higher taxonomic levels (genus and Ensatina higher clades was a weak predictor of microbiome composition. These results lead us to conclude that environmental factors are likely playing a more significant role in salamander cutaneous microbiome assemblages than host-specific traits.
Phylogenetic analysis of Common Garter Snake (Thamnophis sirtalis) stomach contents detects cryptic range of a secretive salamander (Ensatina eschscholtzii oregonensis) Herpetological Conservation and Biology 5(3):395–402
Sean B. Reilly; Andrew D Gottsho; Justin M. Garwood; Bryan. Jennings
Given the current global amphibian decline, it is crucial to obtain accurate and current information regarding species distributions. Secretive amphibians such as plethodontid salamanders can be difficult to detect in many cases, especially in remote, high elevation areas. We used molecular phylogenetic analyses to identify three partially digested salamanders palped...
Full Text Available 9380 |pid:none) Porphyromonas gingivalis ATCC 33... 34 5.5 FJ151945_1( FJ151945 |pid:none) Ensatina eschscholtzii xanthoptica...... 34 7.2 FJ151867_1( FJ151867 |pid:none) Ensatina eschscholtzii xanthoptica...8_1( FJ151878 |pid:none) Ensatina eschscholtzii xanthoptica... 33 9.4 (Q980T8) RecName: Full=DNA ligase; EC=...18.104.22.168; AltName:... 33 9.4 FJ151848_1( FJ151848 |pid:none) Ensatina eschscholtzii xanthoptica...... 33 9.4 FJ151923_1( FJ151923 |pid:none) Ensatina eschscholtzii xanthoptica... 33 9.4 >BC0709
Nov 6, 2014 ... expansion of human land use (Burgess &. Sharp, 1981). Habitat .... patches with houses inside; farming inside- ..... Macmillan Publishing Company, New. York. 639pp. ... Compensatory behavior of Ensatina eschscholtzii in ...
M. L. Best; H. H. Welsh
Woodland (Plethodontid) salamanders are the most abundant vertebrates in North American forests, functioning as predators on invertebrates and prey for higher trophic levels. We investigated the role of Ensatina (Ensatina eschscholtzii) in regulating invertebrate numbers and leaf litter retention in a northern California forest. Our objective was...
Full Text Available Change in digit number, particularly digit loss, has occurred repeatedly over the evolutionary history of tetrapods. Although digit loss has been documented among distantly related species of salamanders, it is relatively uncommon in this amphibian order. For example, reduction from five to four toes appears to have evolved just three times in the morphologically and ecologically diverse family Plethodontidae. Here we report a molecular phylogenetic analysis for one of these four-toed lineages--the Eurycea quadridigitata complex (dwarf salamanders--emphasizing relationships to other species in the genus. A multilocus phylogeny reveals that dwarf salamanders are paraphyletic with respect to a complex of five-toed, paedomorphic Eurycea from the Edwards Plateau in Texas. We use this phylogeny to examine evolution of digit number within the dwarf-Edwards Plateau clade, testing contrasting hypotheses of digit loss (parallelism among dwarf salamanders versus digit gain (re-evolution in the Edwards Plateau complex. Bayes factors analysis provides statistical support for a five-toed common ancestor at the dwarf-Edwards node, favoring, slightly, the parallelism hypothesis for digit loss. More importantly, our phylogenetic results pinpoint a rare event in the pedal evolution of plethodontid salamanders.
Bursey, Charles R; Goldberg, Stephen R
Oswaldocruzia cartagoensis n. sp. (Strongylida: Molineidae) from the intestines of Bolitoglossa subpalmata (Caudata: Plethodontidae) is described and illustrated. Oswaldocruzia cartagoensis n. sp. represents the 86 th species assigned to the genus and the 39th species from the Neotropical region. It is most similar to the Neotropical species of the genus that possess type I bursa, i.e., Oswaldocruzia bonsi , Oswaldocruzia brasiliensis , Oswaldocruzia lopesi , Oswaldocruzia neghmei , and Oswaldocruzia vitti . Of these, O. bonsi, O. brasiliensis, and O. neghmei lack cervical alae, rib 4 in individuals of O. vitti reaches the edge of the bursal membrane, species of O. lopesi and O. cartagoensis can be separated on the basis of spicule structure, the blade in O. lopesi is bifurcate, and that of O. cartagoensis terminates in 6-8 fine points. In addition to the new species of Oswaldocruzia, Cosmocera parva, Cosmocera podicipinus, and acanthocephalan cystacanths were also found.
Desnitskiy, Alexey G; Litvinchuk, Spartak N
The order Caudata includes about 660 species and displays a variety of important developmental traits such as cleavage pattern and egg size. However, the cleavage process of tailed amphibians has never been analyzed within a phylogenetic framework. We use published data on the embryos of 36 species concerning the character of the third cleavage furrow (latitudinal, longitudinal or variable) and the magnitude of synchronous cleavage period (up to 3-4 synchronous cell divisions in the animal hemisphere or a considerably longer series of synchronous divisions followed by midblastula transition). Several species from basal caudate families Cryptobranchidae (Andrias davidianus and Cryptobranchus alleganiensis) and Hynobiidae (Onychodactylus japonicus) as well as several representatives from derived families Plethodontidae (Desmognathus fuscus and Ensatina eschscholtzii) and Proteidae (Necturus maculosus) are characterized by longitudinal furrows of the third cleavage and the loss of synchrony as early as the 8-cell stage. By contrast, many representatives of derived families Ambystomatidae and Salamandridae have latitudinal furrows of the third cleavage and extensive period of synchronous divisions. Our analysis of these ontogenetic characters mapped onto a phylogenetic tree shows that the cleavage pattern of large, yolky eggs with short series of synchronous divisions is an ancestral trait for the tailed amphibians, while the data on the orientation of third cleavage furrows seem to be ambiguous with respect to phylogeny. Nevertheless, the midblastula transition, which is characteristic of the model species Ambystoma mexicanum (Caudata) and Xenopus laevis (Anura), might have evolved convergently in these two amphibian orders.
Budzik, Karolina A; Żuwała, Krystyna; Kerney, Ryan
The latest research on direct developing caecilian and anuran species indicate presence of only one generation of taste organs during their ontogeny. This is distinct from indirect developing batrachians studied thus far, which possess taste buds in larvae and anatomically distinct taste discs in metamorphs. This study is a description of the tongue and taste organ morphology and development in direct developing salamander Plethodon cinereus (Plethodontidae) using histology and electron microscopy techniques. The results reveal two distinct stages tongue morphology (primary and secondary), similar to metamorphic urodeles, although only one stage of taste organ morphology. Taste disc sensory zones emerge on the surface of the oropharyngeal epithelium by the end of embryonic development, which coincides with maturation of the soft tongue. Taste organs occur in the epithelium of the tongue pad (where they are situated on the dermal papillae), the palate and the inner surface of the mandible and the maxilla. Plethodon cinereus embryos only possess taste disc type taste organs. Similar to the direct developing anuran Eleutherodactylus coqui (Eleutherodactylidae), these salamanders do not recapitulate larval taste bud morphology as an embryo. The lack of taste bud formation is probably a broadly distributed feature characteristic to direct developing batrachians. J. Morphol. 277:906-915, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Daldinia eschscholtzii (Ascomycota, Xylariaceae isolated from the Brazilian Amazon: taxonomic features and mycelial growth conditions Daldinia eschscholzii (Ascomycota, Xylariaceae isolado na Amazônia brasileira: características taxonômicas e condições de crescimento micelial
Kamila Tomoko Yuyama
Full Text Available The Amazon has a high diversity of fungi, including species of the genus Daldinia (Ascomycota, Xylariaceae, which produce secondary metabolites with recognized nematicidal and antimicrobial activity. The ecological role of Daldinia is important, as stromata serve as refuges to many insects and arthropodes, and the fungi contribute to the degradation of vegetable organic matter. The aim of this study was to analyze the taxonomic features and mycelial growth conditions in vitro of a Daldinia specimen collected in the Brazilian Amazon. Morphological and molecular studies of the fungus identified it as D. eschscholtzii. To evaluate mycelial growth, we cultivated the fungus at 20, 25, 30, 35, and 40 °C in malt extract-peptone agar (MEPA, malt extract-peptone (MEP, potato dextrose (PD, and minimum medium (MM. The best mycelial growth occurred at 35 °C, although the greatest amount of biomass was obtained at 25 °C and 30 °C. PD proved to be the best medium for biomass production.A Amazônia apresenta alta diversidade de fungos, incluindo Daldinia (Ascomycota, Xylariaceae, cujas espécies produzem metabólitos secundários com reconhecida atividade antimicrobiana e nematicida. O papel ecológico é importante, visto que estromas servem de abrigo para muitos insetos e artrópodes, além de contribuir na degradação da matéria orgânica vegetal. O objetivo desse estudo foi analizar as características taxonômicas e as condições do crescimento micelial in vitro de um espécime de Daldinia coletado na Amazônia brasileira. Estudos morfológicos e moleculares do fungo o indetificaram como D. eschscholtzii. Para avaliação do crescimento micelial o fungo foi cultivado nas temperaturas de 20, 25, 30, 35 e 40 °C e nos meios de cultura extrato de malte-peptona ágar (EMPA, extrato de malte-peptona (EMP, batata dextrose (BD e meio mínimo (MM. O melhor crescimento micelial ocorreu a 35 °C, entretanto, a maior quantidade de biomassa foi obtida a 25 e
Jessica A. Homyack
Full Text Available Intensively-managed forest (IMF ecosystems support environmental processes, retain biodiversity and reduce pressure to extract wood products from other forests, but may affect species, such as plethodontid salamanders, that are associated with closed canopies and possess limited vagility. We describe: (1 critical aspects of IMF ecosystems; (2 effectiveness of plethodontid salamanders as barometers of forest change; (3 two case studies of relationships between salamanders and coarse woody debris (CWD; and (4 research needs for effective management of salamanders in IMF ecosystems. Although plethodontid salamanders are sensitive to microclimate changes, their role as ecological indicators rarely have been evaluated quantitatively. Our case studies of CWD and salamanders in western and eastern forests demonstrated effects of species, region and spatial scale on the existence and strength of relationships between plethodontid species and a “critical” microhabitat variable. Oregon slender salamanders (Batrachoseps wrighti were more strongly associated with abundance of CWD in managed second growth forests than ensatina salamanders (Ensatina eschscholtzii. Similarly, CWD was not an important predictor of abundance of Appalachian salamanders in managed hardwood forest. Gaining knowledge of salamanders in IMF ecosystems is critical to reconciling ecological and economic objectives of intensive forest management, but faces challenges in design and implementation.
Pereira, Ricardo J; Monahan, William B; Wake, David B
Reproductive isolation (RI) is widely accepted as an important "check point" in the diversification process, since it defines irreversible evolutionary trajectories. Much less consensus exists about the processes that might drive RI. Here, we employ a formal quantitative analysis of genetic interactions at several stages of divergence within the ring species complex Ensatina eschscholtzii in order to assess the relative contribution of genetic and ecological divergence for the development of RI. By augmenting previous genetic datasets and adding new ecological data, we quantify levels of genetic and ecological divergence between populations and test how they correlate with a restriction of genetic admixture upon secondary contact. Our results indicate that the isolated effect of ecological divergence between parental populations does not result in reproductively isolated taxa, even when genetic transitions between parental taxa are narrow. Instead, processes associated with overall genetic divergence are the best predictors of reproductive isolation, and when parental taxa diverge in nuclear markers we observe a complete cessation of hybridization, even to sympatric occurrence of distinct evolutionary lineages. Although every parental population has diverged in mitochondrial DNA, its degree of divergence does not predict the extent of RI. These results show that in Ensatina, the evolutionary outcomes of ecological divergence differ from those of genetic divergence. While evident properties of taxa may emerge via ecological divergence, such as adaptation to local environment, RI is likely to be a byproduct of processes that contribute to overall genetic divergence, such as time in geographic isolation, rather than being a direct outcome of local adaptation.
Carpenter, D.W.; Jung, R.E.; Sites, J.W.
The Shenandoah salamander (Plethodon shenandoah) is restricted to three isolated talus outcrops in Shenandoah National Park, VA, USA and has one of the smallest ranges of any tetrapod vertebrate. This species was listed as endangered under the US Endangered Species Act in 1989 over concern that direct competition with the red-backed salamander (Plethodon cinereus), successional habitat changes, and human impacts may cause its decline and possible extinction. We address two issues herein: (1) whether extensive introgression (through long-term hybridization) is present between the two species and threatens the survival of P. shenandoah, and (2) the level of population structure within P. shenandoah. We provide evidence from mtDNA haplotypes that shows no genetic differentiation among the three isolates of P. shenandoah, suggesting that their fragmentation is a geologically recent event, and/or that the isolates are still connected by occasional gene flow. There is also no evidence for extensive introgression of alleles in either direction between P. cinereus and P. shenandoah, which suggests that P. shenandoah may not be in danger of being genetically swamped out through hybridization with P. cinereus.
Full Text Available Populations of Mexican plethodontid salamanders have been surveyed non-systematically over the last 25 years. In light of many reports of disappearance of amphibians around the world, we checked for persistence of reported species at ten of these sites. All of the commoner species persist (we observed individuals representing a total of 30 species. While observed densities of many species of Mexican plethodontids are lower to much lower than was the case 20 to 25 years ago, evidence for recent extinctions, such as has been reported for amphibian taxa elsewhere, is equivocal or lacking. Habitat modification has contributed to difficulties in finding certain species.Poblaciones de varias especies de salamandras pletodóntidas en México han sido monitoreadas de manera no sistemática durante los últimos 25 años. Diez de éstas poblaciones fueran visitadas recientemente con el propósito de verificar la persistencia de las especies reportadas para dichas localidades. Nuestras observaciones confirman la persistencia local de más de 30 especies cuyo estatus era desconocido, aunque la frecuencia de observación de estas especies es en general menor que en fechas anteriores. Estas observaciones son particularmente relevantes dada la situación actual de preocupación por la disminución mundial de anfibios.
Acosta Galvis Andrés R.
Full Text Available Se describe una nueva especie del genero Bolitoglossa del grupo alfa (sensu Wake & Lynch, 1976 denominada Bolitoglossa lozanoi de las selvas húmedas relictuales del valle del Río Magdalena en La Cordillera Central de Colombia (loe. typ.: Río La Miel, Mpio. La Victoria, Departamento de Caldas, 500 m.s.n.m.; la nueva especie es reconocible por su cuerpo robusto, las palmeaduras manuales y pediales extensas, su patrón cromático ventral café con punteaduras café más oscuras y crema, ojos no protuberantes y la talla corporal relativamente grande entre las especies de salamandras del país. A new species of the genus Bolitoglossa, of the alpha group (sensu Wake & Lynch, 1976 named Bolitoglossa lozanoi from the relictual humid forest from the Magdalena Valley on the eastern slope ofthe central Andes Mountain range in Colombia (type locality: La Miel River, Mpio. La Victoria, Dept. of Caldas, 500 m.s.n.m.. The new species is mainly recognized by the presence of a robust body, extensively webbed hands and toes, a brownish ventral chromatic pattern with small darker brown and cream dots, non-protuberant eyes and a relatively large size.
Full Text Available We describe three new species of minute salamanders, genus Thorius, from the Sierra Madre del Sur of Oaxaca, Mexico. Until now only a single species, T. minutissimus, has been reported from this region, although molecular data have long shown extensive genetic differentiation among geographically disjunct populations. Adult Thorius pinicola sp. nov., T. longicaudus sp. nov., and T. tlaxiacus sp. nov. are larger than T. minutissimus and possess elliptical rather than oval nostrils; T. pinicola and T. longicaudus also have longer tails. All three new species occur west of the range of T. minutissimus, which has the easternmost distribution of any member of the genus. The new species are distinguished from each other and from other named Thorius in Oaxaca by a combination of adult body size, external morphology and osteology, and by protein characters (allozymes and differences in DNA sequences. In addition, we redescribe T. minutissimus and a related species, T. narisovalis, to further clarify the taxonomic status of Oaxacan populations and to facilitate future studies of the remaining genetically differentiated Thorius that cannot be satisfactorily assigned to any named species. Populations of all five species considered here appear to have declined dramatically over the last one or two decades and live specimens are difficult to find in nature. Thorius may be the most endangered genus of amphibians in the world. All species may go extinct before the end of this century.
Full Text Available Eggs and hatchlings of Pseudoeurycea c. cephalica from Parque Nacional Lagunas de Zempoala, Morelos, Mexico are described for the first time. The eggs are similar to eggs of P. cephalica manni and P. belli in being unstranded. Egg capsules resemble P. nigromaculata and P. juarezi in having two gelatinous envelopes. The embryos have extensively webbed hands and feet with a continuous reduction in webbing during embryogenesis, supporting the hypothesis that webbing of the feet is a paedomorphic character. The hatchlings are uniform grayish-black dorsally and slightly paler ventrally. They are robust with broad heads and short tails and lack both vomerine and maxillary teeth. Lack of dentition has previously been found in juveniles of P. belli.Se describe por primera vez huevos y recién nacidos de Pseudoeurycea cephalica cephalica procedentes del Parque Nacional Lagunas de Zempoala, Morelos, México. Los huevos se paracen a los de P. cephalica manni y P. belli en que no están unidos entre sí por ningún cordón. Se parecen en cuanto a constitución a los de P. nigromaculata y P. juarezi en tener dos capas gelatinosas. Los embriones tienen los pies y manos palmeados, produciéndose una reducción de la superficie palmeada a lo largo de la embriogénesis, lo cual confirma que el palmeado de pies y manos es un carácter pedomórfico. Los recién nacidos son de color gris negruzco, uniforme dorsalmente y de color más claro ventralmente. Son robustos, con cabeza ancha, cola corta y carecen de dientes tanto vomerinos como maxilares. Esta falta de dentición ya fue encontrada anteriormente en juveniles de P. belli.
Jéssica Barata da Silva
Full Text Available Plethodontid salamanders of genus Bolitoglossa constitute the largest and most diverse group of salamanders, including around 20% of living caudate species. Recent studies have indicated the occurrence of five recognized species in the Brazilian Amazon Rainforest. We present here the first cytogenetic data of a Brazilian salamander, which may prove to be a useful by contribution to the cytotaxonomy of the genus. Specimens were collected near the "type" locality (Utinga, Belém, PA, Brazil. Chromosomal preparations from duodenal epithelial cells and testes were subjected to Giemsa staining, C-banding and DAPI/CMA3 fluorochrome staining. All specimens showed a karyotype with 13 bi-armed chromosome pairs (2n = 26. Nucleolar Organizer Regions, evidenced by CMA3, were located distally on the long arm of pair 7 (7q. DAPI+ heterochromatin was predominantly centromeric, with some small pericentromeric bands. Although the C-banding patterns of other Bolitoglossa species are so far unknown, cytogenetic studies conducted in other Plethodontid salamanders have demonstrated that pericentromeric heterochromatin is a useful cytological marker for identifying interspecific homeologies. Species diversification is usually accompanied by chromosomal changes. Therefore, the cytogenetic characterization of Bolitoglossa populations from the middle and western Brazilian Amazon Basin could identify differences which may lead to the identification of new species.
Full Text Available Abstract Background A major goal in evolutionary biology is to understand the evolution of phenotypic diversity. Both natural and sexual selection play a large role in generating phenotypic adaptations, with biomechanical requirements and developmental mechanisms mediating patterns of phenotypic evolution. For many traits, the relative importance of selective and developmental components remains understudied. Results We investigated ontogenetic trajectories of foot morphology in the eight species of European plethodontid cave salamander to test the hypothesis that adult foot morphology was adapted for climbing. Using geometric morphometrics and other approaches, we found that developmental patterns in five species displayed little morphological change during growth (isometry, where the extensive interdigital webbing in adults was best explained as the retention of the juvenile morphological state. By contrast, three species exhibited significant allometry, with an increase in interdigital webbing during growth. Phylogenetic analyses revealed that multiple evolutionary transitions between isometry and allometry of foot webbing have occurred in this lineage. Allometric parameters of foot growth were most similar to those of a tropical species previously shown to be adapted for climbing. Finally, interspecific variation in adult foot morphology was significantly reduced as compared to variation among juveniles, indicating that ontogenetic convergence had resulted in a common adult foot morphology across species. Conclusions The results presented here provide evidence of a complex history of phenotypic evolution in this clade. The common adult phenotype exhibited among species reveals that selection plays an important part in generating patterns of foot diversity in the group. However, developmental trajectories arriving at this common morphology are distinct; with some species displaying developmental stasis (isometry, while others show an increase in foot webbing during growth. Thus, multiple developmental solutions exist to the same evolutionary challenge. Our findings underscore the importance of examining morphological adaptations from multiple perspectives, and emphasize that both selective hypotheses and developmental processes must be considered for a more comprehensive understanding of phenotypic evolution.
Andrés R. Acosta-Galvis
Full Text Available Eight species of salamanders are recognized to Cordillera Oriental of Colombia. Here we describe a new species of the genus Bolitoglossa, named Bolitoglossa guaneae sp. nov. The highest number of species of this genus is found in the cloud forests located in the western flank of the Cordillera Oriental.
Acosta Galvis, Andrés R.; Restrepo, Ana E.
Se describe una nueva especie del genero Bolitoglossa del grupo alfa (sensu Wake & Lynch, 1976) denominada Bolitoglossa lozanoi de las selvas húmedas relictuales del valle del Río Magdalena en La Cordillera Central de Colombia (loe. typ.: Río La Miel, Mpio. La Victoria, Departamento de Caldas, 500 m.s.n.m.); la nueva especie es reconocible por su cuerpo robusto, las palmeaduras manuales y pediales extensas, su patrón cromático ventral café con punteaduras café más oscuras y crema, ojos no pro...
Alegría Coto, José Roberto
Tesis (Magister Scientiae)--Universidad de Costa Rica. Comision del Programa de Estudios de Posgrado en Biología, 1988. UCR::Investigación::Sistema de Estudios de Posgrado::Ciencias Básicas::Maestría Académica en Biología
David M Darda
Full Text Available Osteological variation is recorded among and within four of the most distinctive species of the Mexican salamander genus Chiropterotriton. Analysis of the data is consistent with the monophyletic status of the genus and documents previously unrecorded intraspecific and interspecific variation. Most of the recorded variation involves qualitative and quantitative proportional differences, but four fixed differences constitute autapomorphic states that affirm and diagnose some species (C. dimidiatus, C. magnipes. Osteological variation in 15 characters is analyzed with respect to predictions generated from four hypotheses: 1 phylogeny, 2 adaptation to specific habitats (the four species include cave-dwelling, terrestrial, and arboreal forms, 3 size-free shape, and 4 size. High levels of intraspecific variation suggest that the characters studied are not subject to rigid functional constraints in salamanders, regardless of size. The pattern predicted by the hypothesis based on size differences seen among these four Chiropterotriton species matches most closely the observed pattern of relative skull robustness. Since size change and heterochrony are often associated in plethodontid evolution, it is likely that changes in developmental timing play a role in the morphological transitions among these morphologically diverse taxa. Webbed feet, miniaturization, body shape, and an unusual tarsal arrangement are morphologies exhibited in species of Chiropterotrition that are shown to be homoplastic with other clades of tropical plethodontids. Although extensive homoplasy in salamanders might be seen as a roadblock to unraveling phylogenetic hypotheses, the homologous developmental systems that appear to underlie such homoplasy may reveal common and consistent evolutionary processes at work.
Townsend, Josiah H; Medina-flores, Melissa; Reyes-Calderón, Onán; Austin, James D
The highlands of northeastern Honduras remain under-characterized in terms of biological diversity, as exemplified by the regularity of new amphibian and reptile taxa discoveries. Following the recent description of a new species of Nototriton from the Sierra de Agalta in northeastern Honduras, we report the discovery of a second new species of Nototriton from the nearby Parque Nacional Montaña de Botaderos. This new taxon, Nototriton mime sp. nov., is distinguished from other Nototriton by its distinctive pale brown dorsal coloration in adult males, relatively large nares, a relatively broad head, mitochondrial sequence divergence, and phylogenetic relationships, and is geographically isolated from other populations of Nototriton.
Monahan William B
Full Text Available Abstract Background In the mid 20th century, Ernst Mayr and Theodosius Dobzhansky championed the significance of circular overlaps or ring species as the perfect demonstration of speciation, yet in the over 50 years since, only a handful of such taxa are known. We developed a topographic model to evaluate whether the geographic barriers that favor processes leading to ring species are common or rare, and to predict where other candidate ring barriers might be found. Results Of the 952,147 geographic barriers identified on the planet, only about 1% are topographically similar to barriers associated with known ring taxa, with most of the likely candidates occurring in under-studied parts of the world (for example, marine environments, tropical latitudes. Predicted barriers separate into two distinct categories: (i single cohesive barriers (2, associated with taxa that differentiate at smaller spatial scales (salamander: Ensatina eschscholtzii; tree: Acacia karroo; and (ii composite barriers - formed by groups of barriers (each 184,000 to 1.7 million km2 in close geographic proximity (totaling 1.9 to 2.3 million km2 - associated with taxa that differentiate at larger spatial scales (birds: Phylloscopus trochiloides and Larus (sp. argentatus and fuscus. When evaluated globally, we find a large number of cohesive barriers that are topographically similar to those associated with known ring taxa. Yet, compared to cohesive barriers, an order of magnitude fewer composite barriers are similar to those that favor ring divergence in species with higher dispersal. Conclusions While these findings confirm that the topographic conditions that favor evolutionary processes leading to ring speciation are, in fact, rare, they also suggest that many understudied natural systems could provide valuable demonstrations of continuous divergence towards the formation of new species. Distinct advantages of the model are that it (i requires no a priori information on the
Arias, Erick; Kubicki, Brian
A new salamander belonging to the genus Nototriton, subgenus Nototriton, is described from the Caribbean slopes of the southeastern Cordillera de Talamanca in Costa Rica, within Parque Internacional La Amistad, at an elevation ca. 1500 m a.s.l. This new taxon is distinguished from its congeners by its morphological characteristics and by its differentiation in DNA sequences of the 16S rRNA, cytochrome oxidase subunit I (COI), and cytochrome b mitochondrial genes. This new species represents the southernmost extension known for the genus Nototriton.
Means, D Bruce; Lamb, Jennifer Y; Bernardo, Joseph
The Coastal Plain of the southeastern U. S. is one of the planet's top biodiversity hotspots and yet many taxa have not been adequately studied. The plethodontid salamander, Desmognathus auriculatus, was originally thought to occur from east Texas to Virginia, a range spanning dozens of interfluves and large river systems. Beamer and Lamb (2008) found five independent mitochondrial lineages of what has been called D. auriculatus in the Atlantic Coastal Plain, but did not examine the extensive distribution of D. auriculatus in the Gulf Coastal Plain. We present morphological and molecular genetic data distinguishing two evolutionarily independent and distantly related lineages that are currently subsumed under the taxon D. auriculatus in the eastern Gulf Coastal Plain. We describe one of these as a new species, Desmognathus valentinei sp. nov., and assign the second one to D. auriculatus which we formally redescribe.
Mccranie, James R; Rovito, Sean M
We describe a new species of the plethodontid salamander genus Cryptotriton from Honduras after comparing morphological, molecular, and osteological data from the holotype to that of the other nominal forms of the genus. The new species differs from all of the known species of Cryptotriton in at least one character from all three datasets. We also suggest placing C. wakei in the synonymy of C. nasalis after examining the morphological and osteological characters of the single known specimen of C. wakei.
Stark, Tariq; Laurijssens, Carlijn; Weterings, Martijn; Martel, An; Köhler, Gunther; Pasmans, Frank
Amphibians are the most threatened terrestrial vertebrates on the planet and are iconic in the global biodiversity crisis. Their global decline caused by the fungal agent Batrachochytrium dendrobatidis (Bd) is well known. Declines of Mesoamerican salamanders of the family Plethodontidae, mainly
Kroll, Andrew J.; Garcia, Tiffany S.; Jones, Jay E.; Dugger, Catherine; Murden, Blake; Johnson, Josh; Peerman, Summer; Brintz, Ben; Rochelle, Michael
Plethodontid salamanders are diverse and widely distributed taxa and play critical roles in ecosystem processes. Due to salamander use of structurally complex habitats, and because only a portion of a population is available for sampling, evaluation of sampling designs and estimators is critical to provide strong inference about Plethodontid ecology and responses to conservation and management activities. We conducted a simulation study to evaluate the effectiveness of multi-scale and hierarchical single-scale occupancy models in the context of a Before-After Control-Impact (BACI) experimental design with multiple levels of sampling. Also, we fit the hierarchical single-scale model to empirical data collected for Oregon slender and Ensatina salamanders across two years on 66 forest stands in the Cascade Range, Oregon, USA. All models were fit within a Bayesian framework. Estimator precision in both models improved with increasing numbers of primary and secondary sampling units, underscoring the potential gains accrued when adding secondary sampling units. Both models showed evidence of estimator bias at low detection probabilities and low sample sizes; this problem was particularly acute for the multi-scale model. Our results suggested that sufficient sample sizes at both the primary and secondary sampling levels could ameliorate this issue. Empirical data indicated Oregon slender salamander occupancy was associated strongly with the amount of coarse woody debris (posterior mean = 0.74; SD = 0.24); Ensatina occupancy was not associated with amount of coarse woody debris (posterior mean = -0.01; SD = 0.29). Our simulation results indicate that either model is suitable for use in an experimental study of Plethodontid salamanders provided that sample sizes are sufficiently large. However, hierarchical single-scale and multi-scale models describe different processes and estimate different parameters. As a result, we recommend careful consideration of study questions
Andrew J Kroll
Full Text Available Plethodontid salamanders are diverse and widely distributed taxa and play critical roles in ecosystem processes. Due to salamander use of structurally complex habitats, and because only a portion of a population is available for sampling, evaluation of sampling designs and estimators is critical to provide strong inference about Plethodontid ecology and responses to conservation and management activities. We conducted a simulation study to evaluate the effectiveness of multi-scale and hierarchical single-scale occupancy models in the context of a Before-After Control-Impact (BACI experimental design with multiple levels of sampling. Also, we fit the hierarchical single-scale model to empirical data collected for Oregon slender and Ensatina salamanders across two years on 66 forest stands in the Cascade Range, Oregon, USA. All models were fit within a Bayesian framework. Estimator precision in both models improved with increasing numbers of primary and secondary sampling units, underscoring the potential gains accrued when adding secondary sampling units. Both models showed evidence of estimator bias at low detection probabilities and low sample sizes; this problem was particularly acute for the multi-scale model. Our results suggested that sufficient sample sizes at both the primary and secondary sampling levels could ameliorate this issue. Empirical data indicated Oregon slender salamander occupancy was associated strongly with the amount of coarse woody debris (posterior mean = 0.74; SD = 0.24; Ensatina occupancy was not associated with amount of coarse woody debris (posterior mean = -0.01; SD = 0.29. Our simulation results indicate that either model is suitable for use in an experimental study of Plethodontid salamanders provided that sample sizes are sufficiently large. However, hierarchical single-scale and multi-scale models describe different processes and estimate different parameters. As a result, we recommend careful consideration of
Macey, J. Robert
A new parsimony analysis of 27 complete mitochondrial genomic sequences is conducted to investigate the phylogenetic relationships of plethodontid salamanders. This analysis focuses on the amount of character conflict between phylogenetic trees recovered from newly conducted parsimony searches and the Bayesian and maximum likelihood topology reported by Mueller et al. (2004, PNAS, 101, 13820-13825). Strong support for Hemidactylium as the sister taxon to all other plethodontids is recovered from parsimony analyses. Plotting area relationships on the most parsimonious phylogenetic tree suggests that eastern North America is the origin of the family Plethodontidae supporting the ''Out of Appalachia'' hypothesis. A new taxonomy that recognizes clades recovered from phylogenetic analyses is proposed.
Hossack, Blake R.; Adams, Michael J.; Campbell Grant, Evan H.; Pearl, Chistopher A.; Bettaso, James B.; Barichivich, William J.; Lowe, Winsor H.; True, Kimberly; Ware, Joy L.; Corn, Paul Stephen
Many declines of amphibian populations have been associated with chytridiomycosis, a disease caused by the aquatic fungus Batrachochytrium dendrobatidis (Bd). Despite the relatively high prevalence of chytridiomycosis in stream amphibians globally, most surveys in North America have focused primarily on wetland-associated species, which are frequently infected. To better understand the distribution and prevalence of Bd in headwater amphibian communities, we sampled 452 tailed frogs (Ascaphus truei and Ascaphus montanus) and 304 stream salamanders (seven species in the Dicamptodontidae and Plethodontidae) for Bd in 38, first- to third-order streams in five montane areas across the United States. We tested for presence of Bd by using PCR on skin swabs from salamanders and metamorphosed tailed frogs or the oral disc of frog larvae. We detected Bd on only seven individuals (0.93%) in four streams. Based on our study and results from five other studies that have sampled headwater- or seep-associated amphibians in the United States, Bd has been detected on only 3% of 1,322 individuals from 21 species. These results differ strongly from surveys in Central America and Australia, where Bd is more prevalent on stream-breeding species, as well as results from wetland-associated anurans in the same regions of the United States that we sampled. Differences in the prevalence of Bd between stream- and wetland-associated amphibians in the United States may be related to species-specific variation in susceptibility to chytridiomycosis or habitat differences.
Maex, Margo; Van Bocxlaer, Ines; Mortier, Anneleen; Proost, Paul; Bossuyt, Franky
Sex pheromones have been shown to constitute a crucial aspect of salamander reproduction. Until now, courtship pheromones of Salamandridae and Plethodontidae have been intensively studied, but information on chemical communication in other urodelan families is essentially lacking. The axolotl (Ambystoma mexicanum, Ambystomatidae) has a courtship display that suggests a key role for chemical communication in the orchestration of its sexual behavior, but no sex pheromones have yet been characterized from this species. Here we combined whole transcriptome analyses of the male cloaca with proteomic analyses of water in which axolotls were allowed to court to show that male axolotls secrete multiple ca. 20 kDa glycosylated sodefrin precursor-like factor (SPF) proteins during courtship. In combination with phylogenetic analyses, our data show that the male cloaca essentially secretes a courtship-specific clade of SPF proteins that is orthologous to salamandrid courtship pheromones. In addition, we identified an SPF protein for which no orthologs have been described from other salamanders so far. Overall, our study advocates a central role for SPF proteins during the courtship display of axolotls and adds knowledge on pheromone use in a previously unexplored deep evolutionary branch of salamander evolution.
Mueller, Rachel Lockridge; Macey, J. Robert; Jaekel, Martin; Wake, David B.; Boore, Jeffrey L.
The evolutionary history of the largest salamander family (Plethodontidae) is characterized by extreme morphological homoplasy. Analysis of the mechanisms generating such homoplasy requires an independent, molecular phylogeny. To this end, we sequenced 24 complete mitochondrial genomes (22 plethodontids and two outgroup taxa), added data for three species from GenBank, and performed partitioned and unpartitioned Bayesian, ML, and MP phylogenetic analyses. We explored four dataset partitioning strategies to account for evolutionary process heterogeneity among genes and codon positions, all of which yielded increased model likelihoods and decreased numbers of supported nodes in the topologies (PP > 0.95) relative to the unpartitioned analysis. Our phylogenetic analyses yielded congruent trees that contrast with the traditional morphology-based taxonomy; the monophyly of three out of four major groups is rejected. Reanalysis of current hypotheses in light of these new evolutionary relationships suggests that (1) a larval life history stage re-evolved from a direct-developing ancestor multiple times, (2) there is no phylogenetic support for the ''Out of Appalachia'' hypothesis of plethodontid origins, and (3) novel scenarios must be reconstructed for the convergent evolution of projectile tongues, reduction in toe number, and specialization for defensive tail loss. Some of these novel scenarios imply morphological transformation series that proceed in the opposite direction than was previously thought. In addition, they suggest surprising evolutionary lability in traits previously interpreted to be conservative.
Mueller, Rachel Lockridge; Boore, Jeffrey L.
Extensive gene rearrangement is reported in the mitochondrial genomes of lungless salamanders (Plethodontidae). In each genome with a novel gene order, there is evidence that the rearrangement was mediated by duplication of part of the mitochondrial genome, including the presence of both pseudogenes and additional, presumably functional, copies of duplicated genes. All rearrangement-mediating duplications include either the origin of light strand replication and the nearby tRNA genes or the regions flanking the origin of heavy strand replication. The latter regions comprise nad6, trnE, cob, trnT, an intergenic spacer between trnT and trnP and, in some genomes, trnP, the control region, trnF, rrnS, trnV, rrnL, trnL1, and nad1. In some cases, two copies of duplicated genes, presumptive regulatory regions, and/or sequences with no assignable function have been retained in the genome following the initial duplication; in other genomes, only one of the duplicated copies has been retained. Both tandem and non-tandem duplications are present in these genomes, suggesting different duplication mechanisms. In some of these mtDNAs, up to 25 percent of the total length is composed of tandem duplications of non-coding sequence that includes putative regulatory regions and/or pseudogenes of tRNAs and protein-coding genes along with otherwise unassignable sequences. These data indicate that imprecise initiation and termination of replication, slipped-strand mispairing, and intra-molecular recombination may all have played a role in generating repeats during the evolutionary history of plethodontid mitochondrial genomes.