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Frog diets are influenced by multiple factors, including morphological constraints, habitat use, and seasonal variation in environmental conditions and food availability. This study combined stomach content analysis (SCA), stable isotope analysis (SIA), and estimates of prey availability to investigate the influence of body size and microhabitat use on seasonal variation of the trophic ecology of two sympatric hylids (Pseudis minuta and Scinax squalirostris). We evaluated two hypotheses: (1) the species with larger body and mouth sizes or broader use of microhabitats will have greater diet breadth, and (2) regardless of differences in morphological traits and microhabitat use, diet breadth of both species will be greater during the warmer of two periods. Pseudis minuta exhibited larger body size and mouth width and revealed broader use of microhabitats (mostly within and near major water bodies), whereas S. squalirostris had smaller body size and mouth gape and was found exclusively within or near phytotelmata (plant-held water bodies). SCA revealed that P. minuta had a more diverse diet than S. squalirostris. Only P. minuta showed temporal dietary differences, but these findings did not corroborate our prediction of greater diet diversity during the warmer and drier period when prey densities were higher. The two species had distinct carbon and nitrogen stable isotope ratios, indicating assimilation of different resources, except during the colder wetter season when their isotope spaces overlapped partially. We concluded that the two hylids did not use the same food resources on account of their differences in morphology and microhabitat use, and environmental seasonality did not influence their feeding strategies. [ABSTRACT FROM AUTHOR]

I describe a new species of frog of the Hylarana signata species complex from Mt. Busa, Sarangani and South Cotobato provinces, southern Mindanao Island, Philippines. The new species is distinguished from all other members of the H. signata complex by a unique combination of characters of external morphology, biochemical allelic variation, and the species' position in phylogeny, estimated by analysis of multilocus DNA sequence data. Justification for recognition of the new species is further supported by marked sequence divergence in mitochondrial and nuclear genes. The new species has been collected only once in >20 yr despite targeted survey efforts on Mindanao, and multiple possible explanations are available to explain its extreme rarity. The recognition of this species, on the basis of a single previously misidentified specimen, accentuates the importance of collecting large sample sizes of specimens during faunistic surveys. Recognition of a new species from a locality that has now been heavily disturbed by commercial logging also emphasizes the extreme conservation importance of the last remaining forest fragments in the southern Philippines. [ABSTRACT FROM AUTHOR]

Presently, only 6 out of 14 species in the frog genus Crossodactylus have had their larvae described. Regarding internal oral morphology, only C. dispar, C. gaudichaudii, and C. trachystomus have had tadpoles described. Furthermore, the osteology of C. gaudichaudii was briefly studied and constitutes the unique reference to the subject within the genus. Here, we describe the tadpole of C. aeneus, including its osteology and internal oral anatomy features, an endemic species of the Atlantic forest biome of Brazil. We also provide data from nature on their microhabitat use and abundance variation throughout the year in the streams at the study site. The external morphology of C. aeneus tadpoles is different from all of Crossodactylus spp. tadpoles described, except for C. gaudichaudii, the adult of which is also morphologically similar to C. aeneus. The osteology of C. aeneus tadpoles is similar to that of Hylodes ornatus (the single species of Hylodidae that has had its chondrocranium described) but the pair of adrostral cartilages present in the chondrocranium of H. ornatus is absent in C. aeneus and the pair of processus muscularis of H. ornatus is comparatively more developed than that of C. aeneus. The overall aspect of the oral internal morphology of C. aeneus is more similar to that of C. gaudichaudii than to other Crossodactylus species described in the literature. Our field data showed that tadpoles of C. aeneus are benthic, and that the most frequently used microhabitats were mud, sand, sand with vegetation, and mud with vegetation, all most frequently in the shallow parts of streams. At the study site in the state of Rio de Janeiro, Brazil, they were more abundant (in all stages of development) during the driest period of the year. Até o momento, apenas 6 de 14 espécies do gênero Crossodactylus tiveram suas larvas descritas. Quanto a morfologia oral interna, somente C. dispar, C. gaudichaudii, e C. tarchystomus tiveram essas características descritas. Além disso, a osteologia de C. gaudichaudii foi estudada superficialmente e é a única referência para o gênero. Neste estudo, nós descrevemos o girinos de C. aeneus, incluindo características da sua osteologia e morfologia oral interna, uma espécie endêmica da Floresta Atlântica, Brasil. Nós também apresentamos resultados sobre o uso do microhabitat e a variação na abundância dos girinos ao longo do ano em riachos da área de estudo. A morfologia oral externa dos girinos de C. aeneus difere das demais espécies do mesmo gênero, exceto de C. gaudichaudii, cujo adulto também é morfologicamente similar a C. aeneus. A osteologia dos girinos de C. aeneus é similar a de Hylodes ornatus (a única espécie de Hylodes que possui o condrocrânio descrito), porém o par de processus muscularis de H. ornatus é comparativamente mais desenvolvido do que de C. aeneus. O aspecto geral da morfologia oral interna de C. aeneus é mais similar a de C. gaudichaudii do que outras espécies do gênero. Nossos resultados de campo mostram que os girinos de C. aeneus são bentônicos e que utilizam mais frequentemente como microhabitats lodo, areia, areia com vegetação e lodo com vegetação, todos predominantemente nas partes mais rasas dos riachos. Ainda, os girinos foram mais abundantes (em todos os estágios de desenvolvimento, durante o período mais seco do ano. [ABSTRACT FROM AUTHOR]