396 resultados para Frogs.


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Toadlets of the genus Brachycephalus are endemic to the Atlantic rainforests of southeastern and southern Brazil. The 14 species currently described have snout-vent lengths less than 18. mm and are thought to have evolved through miniaturization: an evolutionary process leading to an extremely small adult body size. Here, we present the first comprehensive phylogenetic analysis for Brachycephalus, using a multilocus approach based on two nuclear (Rag-1 and Tyr) and three mitochondrial (Cyt b, 12S, and 16S rRNA) gene regions. Phylogenetic relationships were inferred using a partitioned Bayesian analysis of concatenated sequences and the hierarchical Bayesian method (BEST) that estimates species trees based on the multispecies coalescent model. Individual gene trees showed conflict and also varied in resolution. With the exception of the mitochondrial gene tree, no gene tree was completely resolved. The concatenated gene tree was completely resolved and is identical in topology and degree of statistical support to the individual mtDNA gene tree. On the other hand, the BEST species tree showed reduced significant node support relative to the concatenate tree and recovered a basal trichotomy, although some bipartitions were significantly supported at the tips of the species tree. Comparison of the log likelihoods for the concatenated and BEST trees suggests that the method implemented in BEST explains the multilocus data for Brachycephalus better than the Bayesian analysis of concatenated data. Landmark-based geometric morphometrics revealed marked variation in cranial shape between the species of Brachycephalus. In addition, a statistically significant association was demonstrated between variation in cranial shape and genetic distances estimated from the mtDNA and nuclear loci. Notably, B. ephippium and B. garbeana that are predicted to be sister-species in the individual and concatenated gene trees and the BEST species tree share an evolutionary novelty, the hyperossified dorsal plate. © 2011 Elsevier Inc.

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Seventy-seven males of Hypsiboas prasinus from 2 Atlantic forest fragments in the municipalities of Botucatu and Jundiaí, São Paulo State, Brazil, were examined for endoparasites. The frogs were captured in summer (January until March) and winter (July/August) of 2008 and 2009. Thirty-three males (75) from Botucatu were infected with Rhabdias cf. fuelleborni, cosmocerciid nematodes, and Cylindrotaenia americana. Twenty-five tree frogs (78.5) from Jundiaí were infected by Rhabdias cf. fuelleborni, Physaloptera sp., and cosmocerciid nematodes. Only cosmocerciid nematodes presented a statistically significance difference in prevalence (z 4.345; P < 0.001) and mean abundance (t 562.0; P < 0.001) between Botucatu and Jundiaí during the winter. Also, the cosmocerciids exhibited higher mean abundance (t 196.0; P 0.034) in winter when compared with summer at the Jundiaí site. Moreover, to our knowledge, this is the first report of C. americana in the Brazilian Hylidae. This study presents 4 new records of nematodes in H. prasinus. © 2012 American Society of Parasitologists.

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One of the main pesticides used in the cultivation of sugarcane in São Paulo State, Brazil, is Regent®800WG, the main active compound of which is fipronil. Fipronil is a potent insecticide that eliminates pests, including insects resistant to pyrethroids, organophosphates (OP) and carbamates (CA). There is little known on the toxic effects of fipronil on non-target organisms, such as tadpoles of frogs. It is possible that this compound carries a high toxicity for these organisms, since the pesticide can be incorporated into aquatic environments during the rainy season, a time which coincides with the time of amphibian reproduction and the occurrence of tadpoles in the aquatic environment in this region. Thus, the pesticide could be contributing to the decline of amphibians in the northwest region of São Paulo state due to its wide use. This study aimed to test the influence of Regent®800WG on some biochemical systems of tadpoles (such as antioxidant defense systems) at different stages of development. The results of analysis from in vivo exposures demonstrated that only a few parameters in the groups exposed to fipronil responded to exposure to Regent®800WG, results which indicate that the pesticide instigates biochemical responses in tadpoles. Although catalase and glucose-6-phosphate dehydrogenase (G6PDH) were unchanged during the experiments, glutathione-S-transferase (GST) was inhibited in tadpoles, and the activity of glutathione reductase (GR) varied according to the exposure period and pesticide concentration. This data demonstrated the influence of the fipronil formulation on the metabolism of tadpoles, and showed that it can increase their susceptibility to environmental contaminants. © 2013 Elsevier Ltd. All rights reserved.

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Spiny-backed tree frogs of the genus Osteocephalus are conspicuous components of the tropical wet forests of the Amazon and the Guiana Shield. Here, we revise the phylogenetic relationships of Osteocephalus and its sister group Tepuihyla, using up to 6134 bp of DNA sequences of nine mitochondrial and one nuclear gene for 338 specimens from eight countries and 218 localities, representing 89% of the 28 currently recognized nominal species. Our phylogenetic analyses reveal (i) the paraphyly of Osteocephalus with respect to Tepuihyla, (ii) the placement of 'Hyla' warreni as sister to Tepuihyla, (iii) the non-monophyly of several currently recognized species within Osteocephalus and (iv) the presence of low (<1%) and overlapping genetic distances among phenotypically well-characterized nominal species (e.g. O. taurinus and O. oophagus) for the 16S gene fragment used in amphibian DNA barcoding. We propose a new taxonomy, securing the monophyly of Osteocephalus and Tepuihyla by rearranging and redefining the content of both genera and also erect a new genus for the sister group of Osteocephalus. The colouration of newly metamorphosed individuals is proposed as a morphological synapomorphy for Osteocephalus. We recognize and define five monophyletic species groups within Osteocephalus, synonymize three species of Osteocephalus (O. germani, O. phasmatus and O. vilmae) and three species of Tepuihyla (T. celsae, T. galani and T. talbergae) and reallocate three species (Hyla helenae to Osteocephalus, O. exophthalmus to Tepuihyla and O. pearsoni to Dryaderces gen. n.). Furthermore, we flag nine putative new species (an increase to 138% of the current diversity). We conclude that species numbers are largely underestimated, with most hidden diversity centred on widespread and polymorphic nominal species. The evolutionary origin of breeding strategies within Osteocephalus is discussed in the light of this new phylogenetic hypothesis, and a novel type of amplexus (gular amplexus) is described. © 2013 The Norwegian Academy of Science and Letters.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

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Pós-graduação em Aquicultura - FCAV