Genomic SNPs resolve the phylogeny of an ancient amphibian island radiation from the Seychelles.

Unusually for oceanic islands, the granitic Seychelles host multiple lineages of endemic amphibians. This includes an ancient (likely ca. 60 million years) radiation of eight caecilian species, most of which occur on multiple islands.These caecilians have a complicated taxonomic history and their phylogenetic inter-species relationships have been difficult to resolve. Double-digest RAD sequencing (ddRADseq) has been applied extensively to phylogeography and increasingly to phylogenetics but its utility for resolving ancient divergences is less well established. To address this, we applied ddRADseq to generate a genome-wide SNP panel for phylogenomic analyses of the Seychelles caecilians, whose phylogeny has so far not been satisfactorily resolved with traditional DNA markers. Based on 129,154 SNPs, we resolved deep and shallow splits, with strong support. Our findings demonstrate the capability of genome-wide SNPs for evolutionary inference at multiple taxonomic levels and support the recently proposed synonymy of Grandisonia Taylor, 1968 with Hypogeophis Peters, 1879. We revealed three clades of Hypogeophis (large-, medium- and short-bodied) and identify a single origin of the diminutive, stocky-bodied and pointy-snouted phenotype.

What lies beneath? Molecular evolution during the radiation of caecilian amphibians.

BACKGROUND: Evolution leaves an imprint in species through genetic change. At the molecular level, evolutionary changes can be explored by studying ratios of nucleotide substitutions. The interplay among molecular evolution, derived phenotypes, and ecological ranges can provide insights into adaptive radiations. Caecilians (order Gymnophiona), probably the least known of the major lineages of vertebrates, are limbless tropical amphibians, with adults of most species burrowing in soils (fossoriality). This enigmatic order of amphibians are very distinct phenotypically from other extant amphibians and likely from the ancestor of Lissamphibia, but little to nothing is known about the molecular changes underpinning their radiation. We hypothesised that colonization of various depths of tropical soils and of freshwater habitats presented new ecological opportunities to caecilians. RESULTS: A total of 8540 candidate groups of orthologous genes from transcriptomic data of five species of caecilian amphibians and the genome of the frog Xenopus tropicalis were analysed in order to investigate the genetic machinery behind caecilian diversification. We found a total of 168 protein-coding genes with signatures of positive selection at different evolutionary times during the radiation of caecilians. The majority of these genes were related to functional elements of the cell membrane and extracellular matrix with expression in several different tissues. The first colonization of the tropical soils was connected to the largest number of protein-coding genes under positive selection in our analysis. From the results of our study, we highlighted molecular changes in genes involved in perception, reduction-oxidation processes, and aging that likely were involved in the adaptation to different soil strata. CONCLUSIONS: The genes inferred to have been under positive selection provide valuable insights into caecilian evolution, potentially underpin adaptations of caecilians to their extreme environments, and contribute to a better understanding of fossorial adaptations and molecular evolution in vertebrates.

Stem caecilian from the Triassic of Colorado sheds light on the origins of Lissamphibia.

The origin of the limbless caecilians remains a lasting question in vertebrate evolution. Molecular phylogenies and morphology support that caecilians are the sister taxon of batrachians (frogs and salamanders), from which they diverged no later than the early Permian. Although recent efforts have discovered new, early members of the batrachian lineage, the record of pre-Cretaceous caecilians is limited to a single species, Eocaecilia micropodia The position of Eocaecilia within tetrapod phylogeny is controversial, as it already acquired the specialized morphology that characterizes modern caecilians by the Jurassic. Here, we report on a small amphibian from the Upper Triassic of Colorado, United States, with a mélange of caecilian synapomorphies and general lissamphibian plesiomorphies. We evaluated its relationships by designing an inclusive phylogenetic analysis that broadly incorporates definitive members of the modern lissamphibian orders and a diversity of extinct temnospondyl amphibians, including stereospondyls. Our results place the taxon confidently within lissamphibians but demonstrate that the diversity of Permian and Triassic stereospondyls also falls within this group. This hypothesis of caecilian origins closes a substantial morphologic and temporal gap and explains the appeal of morphology-based polyphyly hypotheses for the origins of Lissamphibia while reconciling molecular support for the group's monophyly. Stem caecilian morphology reveals a previously unrecognized stepwise acquisition of typical caecilian cranial apomorphies during the Triassic. A major implication is that many Paleozoic total group lissamphibians (i.e., higher temnospondyls, including the stereospondyl subclade) fall within crown Lissamphibia, which must have originated before 315 million years ago.

Quantitative evidence for the effects of multiple drivers on continental-scale amphibian declines.

Since amphibian declines were first proposed as a global phenomenon over a quarter century ago, the conservation community has made little progress in halting or reversing these trends. The early search for a "smoking gun" was replaced with the expectation that declines are caused by multiple drivers. While field observations and experiments have identified factors leading to increased local extinction risk, evidence for effects of these drivers is lacking at large spatial scales. Here, we use observations of 389 time-series of 83 species and complexes from 61 study areas across North America to test the effects of 4 of the major hypothesized drivers of declines. While we find that local amphibian populations are being lost from metapopulations at an average rate of 3.79% per year, these declines are not related to any particular threat at the continental scale; likewise the effect of each stressor is variable at regional scales. This result - that exposure to threats varies spatially, and populations vary in their response - provides little generality in the development of conservation strategies. Greater emphasis on local solutions to this globally shared phenomenon is needed.

Contributions to the knowledge of amphibians and reptiles from Volta Grande do Xingu, northern Brazil / Contribuições para o conhecimento de anfíbios e répteis da Volta Grande do Xingu, norte do Brasil

The region of Volta Grande do Xingu River, in the state of Pará, presents several kinds of land use ranging from extensive cattle farming to agroforestry, and deforestation. Currently, the Belo Monte Hydroelectric Power Plant affects the region. We present a checklist of amphibians and reptiles of the region and discuss information regarding the spatial distribution of the assemblies based on results of Environmental Programmes conducted in the area. We listed 109 amphibian (Anura, Caudata, and Gymnophiona) and 150 reptile (Squamata, Testudines, and Crocodylia) species. The regional species richness is still considered underestimated, considering the taxonomic uncertainty, complexity and cryptic diversity of various species, as observed in other regions of the Amazon biome. Efforts for scientific collection and studies related to integrative taxonomy are needed to elucidate uncertainties and increase levels of knowledge of the local diversity.

A região da Volta Grande no Rio Xingu, localizada no estado do Pará, apresenta várias frentes de exploração que vão desde a criação animal até área de cultivo, resultando no desmatamento de fragmentos florestais. Atualmente a região está sendo impactada pela implantação da Usina Hidrelétrica de Belo Monte. A partir de dados obtidos através dos Programas de Monitoramento Ambiental realizados na área de influência da UHE Belo Monte, apresentamos uma listagem das espécies de anfíbios e répteis, com comentários sobre a distribuição espacial das assembleias. Foram catalogados 109 espécies de anfíbios (Anura, Caudata e Gymnophiona) e 150 de répteis (Squamata, Testudines e Crocodylia). Considerando as incertezas taxonômicas, a complexidade e a diversidade críptica de várias espécies, a riqueza regional ainda continua subestimada, assim como observado em outras regiões da Amazônia. Esforços direcionados ao aproveitamento científico e estudos que contemplem a taxonomia integrativa são necessários para elucidar as incertezas e aumentar o nível de conhecimento sobre a diversidade da região.

Contributions to the knowledge of amphibians and reptiles from Volta Grande do Xingu, northern Brazil / Contribuições para o conhecimento de anfíbios e répteis da Volta Grande do Xingu, norte do Brasil

Abstract The region of Volta Grande do Xingu River, in the state of Pará, presents several kinds of land use ranging from extensive cattle farming to agroforestry, and deforestation. Currently, the Belo Monte Hydroelectric Power Plant affects the region. We present a checklist of amphibians and reptiles of the region and discuss information regarding the spatial distribution of the assemblies based on results of Environmental Programmes conducted in the area. We listed 109 amphibian (Anura, Caudata, and Gymnophiona) and 150 reptile (Squamata, Testudines, and Crocodylia) species. The regional species richness is still considered underestimated, considering the taxonomic uncertainty, complexity and cryptic diversity of various species, as observed in other regions of the Amazon biome. Efforts for scientific collection and studies related to integrative taxonomy are needed to elucidate uncertainties and increase levels of knowledge of the local diversity.

Resumo A região da Volta Grande no Rio Xingu, localizada no estado do Pará, apresenta várias frentes de exploração que vão desde a criação animal até área de cultivo, resultando no desmatamento de fragmentos florestais. Atualmente a região está sendo impactada pela implantação da Usina Hidrelétrica de Belo Monte. A partir de dados obtidos através dos Programas de Monitoramento Ambiental realizados na área de influência da UHE Belo Monte, apresentamos uma listagem das espécies de anfíbios e répteis, com comentários sobre a distribuição espacial das assembleias. Foram catalogados 109 espécies de anfíbios (Anura, Caudata e Gymnophiona) e 150 de répteis (Squamata, Testudines e Crocodylia). Considerando as incertezas taxonômicas, a complexidade e a diversidade críptica de várias espécies, a riqueza regional ainda continua subestimada, assim como observado em outras regiões da Amazônia. Esforços direcionados ao aproveitamento científico e estudos que contemplem a taxonomia integrativa são necessários para elucidar as incertezas e aumentar o nível de conhecimento sobre a diversidade da região.

Riqueza de herpetofauna de la Finca Universitaria San Julián, Patulul, Suchitepéquez, Guatemala / Herpetofaunal richness of San Julian Universitary Farm, Patulul, Suchitepequez, Guatemala

Aprovechando actividades de docencia de la Unidad de Vida Silvestre de la Facultad de Medicina Veterinaria y Zootecnia de la Universidad de San Carlos de Guatemala, se investigó la riqueza de herpetofauna de la Finca Universitaria San Julián, en Patulul, Suchitepéquez. Se emplearon 3 métodos: (1) captura/avistamiento de especímenes, (2) investigación social, (3) investigación documental. Se recorrió repetidamente un transecto de 4.5 km de longitud a través del agro paisaje de la finca. Los recorridos del transecto abarcaron un período de 10 años (2003-2013), a razón de seis sesiones por año. Cada sesión de campo consistió en un recorrido diurno y un recorrido nocturno del transecto. Se invirtieron aproximadamente 3 hr en cada recorrido diurno y 4 hr en cada recorrido nocturno. El tiempo acumulado de búsqueda fue de 420 hr-transecto. Se recorrió el equivalente a 540 km abarcando elevaciones entre 447 y 550 msnm. En cada sesión de campo participaron entre 3 y 10 personas. Tres excazadores de la finca fueron entrevistados. Se analizaron publicaciones sobre distribución de la herpetofauna para Guatemala. Se generaron dos listas que suman 97 especies. Se discute la calidad y el significado de los datos generados.

The herpetofaunal richness of San Julian Universitary Farm (FUSJ), in Patulul, Suchitepequez, Guatemala, was investigated using three methods: (1) Capture/sighting of specimens, (2) social inquiry and (3) desk research. The field work was distributed over a 10 year period (2003-2013) at a rate of six fieldwork sessions each year. A 4.5 km long transect extending through the agricultural landscape of the farm was run repeatedly. Each fieldwork session included diurnal and nocturnal travels. The accumulated search time was 420 hr-transect. The equivalent to 337.5 of accumulated miles were traveled, including elevations between 1490 and 1833 feet above sea level. Three former hunters were interviewed and asked to identify species they think are present at the FUSJ. Published data were reviewed to determine which species were expected to occur in San Julian. Two lists (amphibians and reptiles) totaling 97 species (including 95 expected, 38 found and 2 not expected) was generated. The quality and significance of our data is discussed.

Characteristics of hemolytic activity induced by skin secretions of the frog Kaloula pulchra hainana

The hemolytic activity of skin secretions obtained by stimulating the frog Kaloula pulchra hainana with diethyl ether was tested using human, cattle, rabbit, and chicken erythrocytes. The skin secretions had a significant concentration-dependent hemolytic effect on erythrocytes. The hemolytic activity of the skin secretions was studied in the presence of osmotic protectants (polyethylene glycols and carbohydrates), cations (Mg2+, Ca2+, Ba2+, Cu2+, and K+), or antioxidants (ascorbic acid, reduced glutathione, and cysteine). Results Depending on their molecular mass, osmotic protectants effectively inhibited hemolysis. The inhibition of skin hemolysis was observed after treatment with polyethylene glycols (1000, 3400, and 6000 Da). Among divalent cations, only 1 mM Cu2+ markedly inhibited hemolytic activity. Antioxidant compounds slightly reduced the hemolytic activity. Conclusions The results suggested that skin secretions of K. pulchra hainana induce a pore-forming mechanism to form pores with a diameter of 1.36-2.0 nm rather than causing oxidative damage to the erythrocyte membrane.

Herpetofauna of Núcleo Experimental de Iguaba Grande, Rio de Janeiro state, Brazil / Herpetofauna do Núcleo Experimental de Iguaba Grande-Rio de Janeiro, Brasil

The Atlantic Rain forest, which is considered the second largest pluvial forest in the American continent, has had an estimated 93% of its original area destroyed. Although studies concerning the herpetofaunal diversity in this biome have been intensified in the past years, its diversity is still underestimated. The Nucleo Experimental de Iguaba Grande (NEIG) is included in an Environmental Protection Area (APA de Sapeatiba) in the Iguaba Grande municipality, Rio de Janeiro state, Brazil (22º 51' S and 42º 10' W). The goal of this study was to conduct an inventory of the reptile and amphibian species that occur in this area between July 2008 and December 2009. We recorded 19 species of amphibians (18 anurans and one caecilian) and 15 species of reptiles (three lizards, 11 snakes and one amphisbaenian). Leptodactylus latrans and L. mystacinus had the highest capture rates among amphibians captured, and among reptiles, Ameiva ameiva, Hemidactylus mabouia and Mabuya agilis had the highest capture rates. Rarefaction curves for both amphibians and reptiles did not reach the asymptote, indicating that the species richness in the NEIG is still underestimated.

A Floresta Atlântica é considerada a segunda maior floresta pluvial tropical do continente americano, embora seja estimado que mais de 93% de sua cobertura original tenha sido destruída. Estudos sobre a diversidade da herpetofauna da Mata Atlântica têm-se intensificado nos últimos anos, embora o conhecimento sobre a diversidade herpetofaunística desse bioma ainda seja considerado subestimado. O Núcleo Experimental de Iguaba Grande (22º 51' S and 42º 10' W) está inserido na Área de Proteção Ambiental de Sapeatiba (APA de Sapeatiba), no município de Iguaba Grande, Estado do Rio de Janeiro, Brasil. Objetivou-se, nesta pesquisa, realizar um levantamento das espécies de anfíbios e répteis de ocorrência nesta área, no período de julho de 2008 a dezembro de 2009. Foram registradas 19 espécies de anfíbios (18 anuros e uma cecília) e 15 espécies de répteis (três lagartos, 11 serpentes e um anfisbenídeo). As espécies Leptodactylus latrans e L. mystacinus representaram as maiores taxas de captura dentre as espécies de anfíbios capturados, enquanto que, para répteis, as maiores taxas de captura foram obtidas para Ameiva ameiva, Hemidactylus mabouia e Mabuya agilis. A curva de rarefação tanto para anfíbios quanto para répteis não atingiu a assíntota, indicando que a riqueza da área ainda está subestimada.

First record of Saprolegnia sp. in an amphibian population in Colombia / Primer registro de Saprolegnia sp. en una población de anfibios en Colombia / Primeiro registro de Saprolegnia sp. numa população de anfíbios na Colômbia

Primer registro de Saprolegnia sp. en una población de anfibios en Colombia. Objetivo. La mayoría de investigaciones en relación al declive de anfibios se han enfocado en la detección del hongo patógeno Batrachochytrium dendrobatidis. Este es el principal patógeno detectado en el mundo. Sin embargo, otras investigaciones han demostrado la presencia de Saprolegnia ferax como un vector mortal en anfibios de Norteamérica. Este trabajo establece una posible transmisión entre especies causada por la presencia de la trucha arcoíris, sugiriendo que el declive de anfibios no solo se atribuye a la presencia de un solo patógeno, sino que puede ser causado por otros patógenos y factores. Materiales y métodos. El estudio revela la presencia de Saprolegnia sp. en la rana de los Andes Atelopus mittermeieri mediante la técnica de impronta con tinción de azul de lactofenol, que permitió la observación de las estructuras típicas de este hongo. Resultados. La importancia de este descubrimiento es la presencia de dos hongos patógenos, B. dendrobatidis y Saprolegnia, afectando simultáneamente una población de anfibios. Este hallazgo enfoca la atención en la eventual presencia de otros microorganismos que podrían estar involucrados individualmente o colectivamente en el declive de especies de anfibios. Conclusiones. Este registro sugiere una posible transmisión entre la trucha arcoiris (Oncorhynchus mykiss), una especie introducida en las montañas de Colombia, que comparte los mismos habitats con diferentes especies de anfibios en el Santuario de Flora y Fauna de Guanentá en el alto río Fonce en la parte media de la Cordillera Oriental de Colombia...

Objective: Most research related to the decline of amphibians has been focused on the detection of the pathogenic fungus Batrachochytrium dendrobatidis. This fungus is the main pathogen detected around the world. However, research has shown the presence of another fungus, Saprolegnia ferax, as a cause of mortality in amphibians in North America. Our study suggests a possible interspecific transmission caused by the presence of rainbow trout; thus, amphibian declines may not be attributable only to the presence of a single pathogen, but to other organisms and factors. Materials and methods. Our study revealed the presence of Saprolegnia sp. in the Andean frog Atelopus mittermeieri using the imprinting technique with lactophenol blue staining, which allowed the typical structures of this fungus to be observed. Results. The importance of this discovery is the presence of two pathogenic fungi, B. dendrobatidis and Saprolegnia, which affecting simultaneously a population of amphibians. This finding brings attention to the eventual presence of other microorganisms that might be involved individually or collectively in the decline of amphibian species. Conclusions. This record suggests a possible transmission between rainbow trout (Oncorhynchus mykiss), an introduced species in the highlands of Colombia, which shares the same habitats with different species of amphibians in the Sanctuary of Flora and Fauna Guanentá in the upper river Fonce in the mid Cordillera Oriental of Colombia...

Primeiro registro de Saprolegnia sp. numa população de anfíbios na Colômbia. Objetivo. A maioria das pesquisas sobre o declínio dos anfíbios tem-se centrado na detecção do fungo patogênico Batrachochytrium dendrobatidis. Este é o principal patógeno encontrado no mundo. No entanto, outros estudos têm demonstrado a presença de Saprolegnia ferax, como vetor mortal de anfíbios de América do Norte. Esta pesquisa estabelece uma possível transmissão entre espécies causada pela presença de truta arco-íris, afirmando que o declínio de anfíbios não só é atribuído à presença de um único patógeno, pudendo ser causado por outros patógenos e fatores. Materiais e métodos. A pesquisa indica a presença de Saprolegnia sp. em rãs dos Andes, Atelopus mittermeieri, pela técnica de impressão com lactofenol-azul-de-algodão, onde observou-se as estruturas típicas deste fungo. Resultados. A importância desta descoberta é a presença de dois fungos (B. dendrobatidis e Saprolegnia) que simultaneamente afetam uma população de anfíbios, concentrando a atenção na presença de outros microorganismos que podem estar envolvidos individualmente ou coletivamente no declínio das espécies de anfíbios. Conclusões. A truta arco-íris (Oncorhynchus mykiss), uma espécie introduzida nas montanhas da Colômbia, que compartilha o mesmo nicho ecológico com Atelopus mittermeieri, no Santuário de Flora e Fauna de Guanentá no Alto Rio Fonce no centro da Cordilheira Oriental da Colômbia, tem sido sugerida por esta pesquisa como o agente transmissor dos fungos as diferentes espécies de anfíbios...

A multilocus timescale for the origin of extant amphibians.

One of the most hotly debated topics in vertebrate evolution is the origin of extant amphibians (Lissamphibia). The recent contribution of molecular data is shedding new light on this debate, but many important questions still remain unresolved. I have assembled a large and comprehensive multilocus dataset (the largest to date in terms of number and heterogeneity of sequence characters) combining mitogenomic and nuclear information from 23 genes for a sufficiently dense taxon sampling with the key major lineages of extant amphibians. This dataset has been used to infer a robust phylogenetic framework and molecular timescale for the origin of extant amphibians employing the most recent phylogenetic and dating methods, as well as several alternative calibration schemes. The monophyly of each extant amphibian order and the sister group relationship between frogs and salamanders (Batrachia hypothesis) are all strongly supported. Dating analyses (all methods and calibration schemes used) suggest that the origin of extant amphibians (divergence between caecilian and batrachians) occurred in the Late Carboniferous, around 315 Mya, and the divergence between frogs and salamanders occurred in the Early Permian, around 290 Mya. These age estimates are more consistent with the fossil record than previous older estimates, and more in line with the Temnospondyli or the Lepospondyli hypotheses of lissamphibian ancestry (although the polyphyly hypothesis cannot be completely ruled out).

Resource polyphenism increases species richness: a test of the hypothesis.

A major goal of evolutionary biology is to identify the causes of diversification and to ascertain why some evolutionary lineages are especially diverse. Evolutionary biologists have long speculated that polyphenism--where a single genome produces alternative phenotypes in response to different environmental stimuli--facilitates speciation, especially when these alternative phenotypes differ in resource or habitat use, i.e. resource polyphenism. Here, we present a series of replicated sister-group comparisons showing that fishes and amphibian clades in which resource polyphenism has evolved are more species rich, and have broader geographical ranges, than closely related clades lacking resource polyphenism. Resource polyphenism may promote diversification by facilitating each of the different stages of the speciation process (isolation, divergence, reproductive isolation) and/or by reducing a lineage's risk of extinction. Generally, resource polyphenism may play a key role in fostering diversity, and species in which resource polyphenism has evolved may be predisposed to diversify.

Herpetofauna dos remanescentes de Mata Atlântica da região de Tapiraí e Piedade, SP, sudeste do Brasil / Herpetofauna of the Atlantic Forest remnants of Tapiraí and Piedade region, São Paulo state, southeastern Brazil

We present the species list of amphibians and reptiles registered in continuous and fragmented Atlantic Forest remnants at Tapiraí and Piedade municipalities, Atlantic Plateau of São Paulo, Brazil. We sampled 21 localities, 15 located within unprotetcted forest fragments and six located at Parque Estadual do Jurupará, the single legal protected area in this region and surroundings. We recorded 47 anurans, one gymnophiona, seven lizards, one amphisbenian, 46 snakes, and one turtle. The specimes were captured by pitfall traps with drift fences, visual and auditive surveys, incidental encounters, local collectors, and, for snakes, by recording scientific collection records. Sampling methods were effective in documenting local herpetofauna, showing the adequacy of the use of complementary methods. Forest remnants at Tapiraí and Piedade have typical species of Atlantic Forest areas, and show higher species richness in comparison with other lists in the Atlantic Plateau. The presence of species known from few localities, or present in threatened species lists, shows that the Atlantic Forest remnants in this region need conservation attention. Although still harboring high herpetofaunal diversity, the remnants are threatened by the effects of forest fragmentation.

Apresentamos aqui a lista de espécies de anfíbios e répteis registradas nos remanescentes de Mata Atlântica contínua e fragmentada da região de Tapiraí e Piedade, Planalto Atlântico de São Paulo, sudeste do Brasil. Amostramos 21 localidades na região, sendo 15 fragmentos florestais e seis localidades do interior e entorno do Parque Estadual do Jurupará, único remanescente legalmente protegido da região. Registramos 47 espécies de anfíbios anuros, uma espécie de gymnophiona, oito espécies de lagartos, uma espécie de anfisbena, 46 espécies de serpentes e uma espécie de quelônio. Esta lista conta com espécimes capturados pelos métodos de armadilhas de interceptação e queda, procura visual e auditiva, encontros ocasionais, capturas por terceiros e, no caso das serpentes, também por registros em coleção científica. A combinação entre métodos foi eficiente na amostragem da herpetofauna da região, evidenciando a necessidade de amostragem com métodos complementares. Os remanescentes de Tapiraí e Piedade apresentam espécies de anfíbios e répteis típicas de áreas de Mata Atlântica e alta riqueza de espécies, em relação a outros estudos realizados no planalto. A presença de espécies de distribuição restrita, ou presentes em listas de fauna ameaçada, reforçam a necessidade de conservação dos remanescentes de Mata Atlântica na região, que apesar de abrigar grande diversidade está ameaçada pelos efeitos da fragmentação florestal.

Morfo-fisiologia dos tecidos hematopoiéticos em Lithobates catesbeianus (Anura, Anphibia) / Morpho-physiology of hematopoietic tissue in Lithobates catesbeianus (Anura, Anphibia)

O estudo de diferentes modelos e microambientes hematopoiéticos permite compreender melhor o processo de manutenção do fenótipo tronco. Os lissanfíbios representam um modelo atraente, por representarem o primeiro animal a ocupar o ambiente terrestre, e provavelmente os primeiros a possuir medula óssea. Considerando que o conhecimento sobre os sítios de hematopoiese em lissanfíbios adultos ainda não está bem estabelecido, este estudo teve como objetivo verificar os principais sítios de hematopoiese no anuro Lithobates catesbeianus adulto. Para tal, foram utilizadas colorações especiais e convencionais em microscopia de campo claro. Anticorpos contra G-CSFR, Epo-R, c-kit, CD34, antígeno de célula-tronco, macrófagos, fator de Von Willebrand e laminina foram também utilizados em microscopia confocal a laser. A atividade hematopoiética foi detectada na medula óssea do fêmur, das vértebras e das falanges dos dedos das patas e no rim. Nenhuma atividade hematopoiética foi identificada no baço nem no fígado. Células imaturas e em mitose foram observadas na circulação sanguínea, indicando a diferenciação de algumas linhagens também ocorre neste compartimento. Células CD34 positivas foram visualizadas na medula óssea e no rim. Osteoblastos e outras células da medula óssea mostraram positividade para c-kit. Células-tronco na medula óssea foram identificadas pelo antígeno de células-tronco (Fall-3). Células G-CSF positivas ocorriam em grupos na medula óssea, no parênquima renal e na circulação sangüínea. Células positivas ao receptor de eritropoetina foram identificadas em associação com os sinusóides e com o endósteo na medula óssea, assim como próximas aos túbulos renais. Este trabalho demonstrou que o principal sítio de hematopoiese é a medula óssea, sendo também o rim um local importante de produção de células sangüíneas, apresentando também a seqüência de diferenciação de algumas linhagens hematopoiéticas, e células imaturas.

Dynamics of the terrestrial amphibian assemblage in a flooded riparian forest fragment in a Neotropical region in the south of Brazil / Dinâmica da comunidade de anfíbios terrestres em um fragmento de floresta ripária na região Neotropical no sul do Brasil

The aim of this study was to analyze the richness, abundance and composition of the terrestrial amphibian assemblage in a flooded riparian forest fragment in a Neotropical region in the south of Brazil over a year (2002-2003). A total of 1,265 terrestrial amphibians were captured, representing 12 species and six families. Leiuperidae represented 41.7 and 56.3 percent of the total number of species and individuals captured, respectively. The amphibian richness and abundance were higher in the Spring-Summer than in the Autumn-Winter period, and these attributes did not change after the flood events. However, the floods homogeneously distributed the amphibian species over the fragment. Our study documented the terrestrial amphibian's use in a riparian forest fragment associated to a floodplain system in the south of Brazil, showing the importance of these habitats as possible dispersal corridors among nearby wetlands.

O objetivo deste estudo foi analisar a riqueza, a abundância e a composição da comunidade de anfíbios terrestres em um fragmento de floresta ripária na região Neotropical no sul do Brasil ao longo de um ano (2002-2003). Um total de 1.265 anfíbios terrestres foi capturado, representando 12 espécies e seis famílias. A família Leiuperidae representou 41,7 e 56,3 por cento do número total de espécies e indivíduos capturados, respectivamente. A riqueza e a abundância de anfíbios foram maiores no período primavera-verão do que no período outono-inverno, e esses atributos não variaram após as inundações. Entretanto, as inundações distribuíram homogeneamente as espécies de anfíbios ao longo do fragmento. Nosso estudo verificou o uso dos anfíbios terrestres em um fragmento de floresta ripária associada a uma planície de inundação no sul do Brasil, destacando a importância desses hábitats como possíveis corredores de dispersão entre áreas úmidas próximas.

Composição e ameaças à conservação dos anfíbios anuros do Parque Estadual de Itapeva, município de Torres, Rio Grande do Sul, Brasil / Composition and threats for conservation of anuran amphibians from Itapeva State Park, Municipality of Torres, Rio Grande do Sul, Brazil

A obtenção de listas de espécies constitui-se no primeiro passo para o desenvolvimento de estratégias de conservação. O Parque Estadual de Itapeva (PEVA) é uma unidade de conservação localizada numa estreita faixa entre a RS-389 (Estrada do Mar), e a praia de Itapeva, no município de Torres, extremo norte da planície costeira do Rio Grande do Sul (29º 21' S e 49º 45' W). No Parque, observa-se a presença de grandes dunas móveis, dunas fixas, floresta paludosa, campos, floresta de restinga, banhados e riachos. Os objetivos deste trabalho são: fornecer uma listagem de espécies de anuros do PEVA, informar os ambientes em que foram encontradas e identificar as ameaças a estes anfíbios na área do Parque. O inventariamento da anurofauna estendeu-se de março de 2000 a março de 2003. As campanhas tiveram freqüência mensal no período de maio de 2000 a março de 2001, e após este período foram realizadas oito campanhas adicionais. As amostragens tiveram a duração média de duas noites e dois dias, envolvendo a visita periódica a todos os ambientes com ocorrência potencial de anfíbios anuros, concentrando-se em áreas alagadas, açudes, poças temporárias, arroios, córregos e outros corpos d'água. As coletas noturnas geralmente iniciavam-se às 20 horas e terminavam às 23 horas. Durante o dia os anuros eram procurados sob troncos, pedras, telhas e em locais próximos a residências. Oito ambientes foram amostrados: dunas primárias (DP), banhados (BD), dunas móveis (DM), dunas fixas (DF), campos alagadiços (CA), capoeira (CP), mata paludosa (MP) e campos secos (CS). Foram registradas 29 espécies de anuros das famílias Hylidae (11 spp.), Leiuperidae (6 spp.), Bufonidae (4 spp.), Leptodactylidae (3 spp.), Brachycephalidae (2 spp.), Cycloramphidae (1 sp.), Microhylidae (1 sp.) e Ranidae (1 sp.). O PEVA, até o momento, é o local com o terceiro maior número de espécies de anuros do Rio Grande do Sul. Duas espécies estão ameaçadas de extinção no Rio Grande do Sul...

A species inventory is the first step to develop conservation strategies. The Itapeva State Park (PEVA) is a protected area located in a narrow zone between RS-389 (Estrada do Mar) and the Itapeva beach, near Torres city, extreme north of the coastal plain of the Rio Grande do Sul State (29º 21' S and 49º 45' W). The Park is covered by mobile dunes, fixed dunes, marshy forest, grasslands, dry forests, wetlands and streams. The aim of this study is to list the anuran species of PEVA, to describe their habitats, and to identify possible impact on these anurans inside the Park. The anuran fauna survey occurred from March 2000 to March 2003. The field trips were monthly from May de 2000 to March 2001 after this period, eigth adicional field trips were done. The surveys comprised two nights and two days. The sampling methods included periodic visits to all environments with potential anuran incidence, wet areas, pools, temporary pools, streams and wetlands. During the day we looked for animals under logs, stones, tiles, and near houses. Nocturnal collections were from 8:00 to 11:00 PM. Eight environments were sampled: primary sand dunes (DP), wetlands (BD), movel dunes (DM), fixed dunes (DF), wet grasslands (CA), "capoeira" (regenerating forest), (CP), marshy forest (MP) and dry grasslands (CS). Twenty-nine anuran species from eight families were recorded: Hylidae (11 spp.), Leiuperidae (6 spp.), Bufonidae (4 spp.), Leptodactylidae (3 spp.), Brachycephalidae (2 spp.), Cycloramphidae (1 sp.), Microhylidae (1 sp.) e Ranidae (1 sp.). To date the PEVA is the area with the third highest number of species in Rio Grande do Sul State.Two species are threatened in Rio Grande do Sul: Haddadus binotatus and Melanophryniscus dorsalis. The main observed threats were: forest drainage, forest fragmentation, presence of invasive species and wetland degradation.

Diversity, natural history and conservation of amphibians and reptiles from the San Vito Region, southwestern Costa Rica

We present an inventory of the amphibians and reptiles of the San Vito de Coto Brus region, including the Las Cruces Biological Station, in southern Costa Rica, which is the result of a survey of the herpetofauna occurring in mountain forest fragments, pastures, coffee plantations, and other disturbed areas. We found 67 species, included 26 species of amphibians and of 41of reptiles. We describe the distribution patterns of the community on the basis of the life zones, elevation, fragmentation, and degree of anthropogenic impact. We also provide some nouvelle data on the systematics of some select taxa, their geographical ranges, microhabitats, activity, and other relevant ecological and natural history features. Finally, we comment on the present conservation status of the herpetofauna in the region. Previous literature and collection records indicate a higher number of species occurring in this area, which suggests that some declines have occurred, especially of amphibians, in last decades. Rev. Biol. Trop. 56 (2): 755-778. Epub 2008 June 30.

En este artículo se presenta un inventario de los anfibios y reptiles de la región de San Vito de Coto Brus incluyendo la Estación de Biología Las Cruces, en el sur de Costa Rica. Se llevó a cabo una evaluación de las poblaciones de anfibios y reptiles presentes en los parches de bosque, potreros, cafetales y otras áreas perturbadas de la región. Como resultado de esta evaluación se registraron 26 especies de anfibios y 41 de reptiles lo que suma un total de 67 especies. Asimismo se describen los patrones generales de distribución de las especies basándose en los tipos de vegetación así como en la altitud, fragmentación y grado de perturbación antrópica en el área. Se proporcionan algunos datos sobre la sistemática de las especies, su distribución geográfica, el microhábitat que ocupan, su actividad y otros datos ecológicos y biológicos relevantes. Finalmente, se presenta una breve discusión sobre la conservación de la herpetofauna en la región. Algunos registros de la literatura y de colecciones científicas muestran que el número de especies de la herpetofauna conocidos en esta región era probablemente mayor, lo que podría indicar que han ocurrido algunas declinaciones importantes de especies, especialmente de anfibios en las últimas décadas.

Herpetofauna of an Atlantic rainforest area (Morro São João) in Rio de Janeiro State, Brazil

We studied the herpetofaunal community from the Atlantic forest of Morro São João, in Rio de Janeiro State, Brazil, and present data on species composition, richness, relative abundance and densities. We combined three sampling methods: plot sampling, visual encounter surveys and pit-fall traps. We recorded sixteen species of amphibians and nine of reptiles. The estimated densities (based on results of plot sampling) were 4.5 ind/100 m2 for amphibians and 0.8 ind/100 m² for lizards, and the overall density (amphibians and lizards) was 5.3 ind/100 m². For amphibians, Eleutherodactylus and Scinax were the most speciose genera with three species each, and Eleutherodactylus binotatus was the most abundant species (mean density of 3.0 frogs/100 m²). The reptile community of Morro São João was dominated by species of the families Gekkonidae and Gymnophtalmidae (Lacertilia) and Colubridae (Serpentes). The gymnophtalmid lizard Leposoma scincoides was the most abundant reptile species (mean density of 0.3 ind/100 m²). We compare densities obtained in our study data with those of other studied rainforest sites in various tropical regions of the world.

Estudamos a comunidade herpetofaunística da Mata Atlântica do Morro São João, Estado do Rio de Janeiro, Brasil, e apresentamos dados da composição, riqueza, abundância relativa e densidade das espécies. Combinamos três metodologias de amostragem: parcelas, encontros visuais e armadilhas de queda. Registramos 16 espécies de anfíbios e 9 espécies de répteis. As densidades estimadas (baseadas nos resultados da amostragem através de parcelas) foram 4.5 ind/100 m² para anfíbios, 0.8 ind/100 m² para lagartos, e a densidade total (anfíbios e répteis) foi 5.3 ind/100 m². Para anfíbios, Eleutherodactylus e Scinax foram os gêneros com maior número de espécies, com três espécies cada, e Eleutherodactylus binotatus foi a espécie mais abundante (densidade média de 3.0 anuros/100 m²). A comunidade de répteis do Morro São João foi dominada por espécies da família Gekkonidae e Gymnophtalmidae (Lacertilia) e Colubridae (Serpentes). O lagarto gimnoftalmídeo Leposoma scincoides foi a espécie de réptil mais abundante (densidade média de 0.3 ind/100 m). Comparamos os dados de densidade obtidos no nosso estudo com os de outros estudos em florestas de várias regiões tropicais do mundo.

Anuros da Reserva Rio das Pedras, Mangaratiba, RJ, Brasil / Anurans at Rio das Pedras Reserve, Mangaratiba, RJ, Brazil

Um estudo de composição de fauna foi realizado em um reduto de Mata Atlântica na região sul Fluminense, município de Mangaratiba, RJ, no período de maio de 1997 a setembro de 2006. As coletas foram feitas mensalmente nos cinco primeiros anos e bimensalmente nos outros cinco anos, totalizando 82 excursões. As visitas tiveram duração média de duas noites, com uma equipe de quatro pessoas, utilizando a metodologia de busca ativa visual e auditiva. Ao todo foram registradas para a região quarenta e uma espécies de vinte e um gêneros, distribuídos em nove famílias: Amphignathodontidae (três), Brachycephalidae (seis), Bufonidae (dois), Centrolenidae (um), Cyclorhamphidae (dois), Hylidae (21), Hylodidae (dois), Leptodactylidae (três) e Microhylidae (um). As espécies foram relacionadas aos diversos micro-ambientes de reprodução encontrados na Reserva Rio das Pedras (ReRP) e foram feitas considerações sobre seu estado de conservação. A distribuição geográfica e a variação altitudinal de Gastrotheca albolineata foram ampliadas. Proceratophrys appendiculata e Bokermannohyla circumdata tiveram também sua variação altitudinal ampliada. Scinax angrensis e Aplastodiscus eugenioi foram incluídas na lista de anfíbios do estado do Rio de Janeiro. A anurofauna da ReRP representa 25 por cento do total de espécies de anuros do estado do Rio de Janeiro, contendo uma espécie ameaçada de extinção na categoria " em perigo" (EN), uma " quase ameaçada" (NT) e outra com distribuição restrita. O número de espécies foi considerado expressivo quando comparado com outras áreas de Mata Atlântica do Estado de São Paulo.

A study of anuran fauna composition was made in an Atlantic Rainforest pocket, at the south of Rio de Janeiro State, municipality of Mangaratiba, from May 1997 to September 2006. Field work was carried out monthly during the first five years and for the next five years every two months, totalizing 82 field trips. Visits had a mean duration of two nights, with a group of four people. Visual and audio active searches were performed. Forty-one species, in twenty-one genera distributed in nine families, were accounted for: Amphignathodontidae (three), Brachycephalidae (six), Bufonidae (two), Centrolenidae (one), Cyclorhamphidae (two), Hylidae (21), Hylodidae (two), Leptodactylidae (three) and Microhylidae (one). The species were related to the many reproductive micro-habitats found at the Rio das Pedras Reserve. The geographical distribution and altitudinal variation of Gastrotheca albolineata were extended. The altitudinal variation of Proceratophrys appendiculata and Bokermannohyla circumdata were also extended. Scinax angrensis and Aplastodiscus eugenioi were included in the list of species from Rio de Janeiro State. The anuran fauna from Rio das Pedras Reserve represents 25 percent of all of Anuran species found in Rio de Janeiro State, including one species " Endangered" - EN and one " Near Threatened" - NT and another species with restricted distribution. The number of species was considered expressive when compared with other Atlantic Rainforest area of São Paulo State.

Amphibian teeth: current knowledge, unanswered questions, and some directions for future research.

Elucidation of the mechanisms controlling early development and organogenesis is currently progressing in several model species and a new field of research, evolutionary developmental biology, which integrates developmental and comparative approaches, has emerged. Although the expression pattern of many genes during tooth development in mammals is known, data on other lineages are virtually non-existent. Comparison of tooth development, and particularly of gene expression (and function) during tooth morphogenesis and differentiation, in representative species of various vertebrate lineages is a prerequisite to understand what makes one tooth different from another. Amphibians appear to be good candidates for such research for several reasons: tooth structure is similar to that in mammals, teeth are renewed continuously during life (=polyphyodonty), some species are easy to breed in the laboratory, and a large amount of morphological data are already available on diverse aspects of tooth biology in various species. The aim of this review is to evaluate current knowledge on amphibian teeth, principally concerning tooth development and replacement (including resorption), and changes in morphology and structure during ontogeny and metamorphosis. Throughout this review we highlight important questions which remain to be answered and that could be addressed using comparative morphological studies and molecular techniques. We illustrate several aspects of amphibian tooth biology using data obtained for the caudate Pleurodeles waltl. This salamander has been used extensively in experimental embryology research during the past century and appears to be one of the most favourable amphibian species to use as a model in studies of tooth development.