396 resultados para Frogs.
Resumo:
The disturbance vicariance hypothesis (DV) has been proposed to explain speciation in Amazonia, especially its edge regions, e. g. in eastern Guiana Shield harlequin frogs (Atelopus) which are suggested to have derived from a cool-adapted Andean ancestor. In concordance with DV predictions we studied that (i) these amphibians display a natural distribution gap in central Amazonia; (ii) east of this gap they constitute a monophyletic lineage which is nested within a pre-Andean/western clade; (iii) climate envelopes of Atelopus west and east of the distribution gap show some macroclimatic divergence due to a regional climate envelope shift; (iv) geographic distributions of climate envelopes of western and eastern Atelopus range into central Amazonia but with limited spatial overlap. We tested if presence and apparent absence data points of Atelopus were homogenously distributed with Ripley's K function. A molecular phylogeny (mitochondrial 16S rRNA gene) was reconstructed using Maximum Likelihood and Bayesian Inference to study if Guianan Atelopus constitute a clade nested within a larger genus phylogeny. We focused on climate envelope divergence and geographic distribution by computing climatic envelope models with MaxEnt based on macroscale bioclimatic parameters and testing them by using Schoener's index and modified Hellinger distance. We corroborated existing DV predictions and, for the first time, formulated new DV predictions aiming on species' climate envelope change. Our results suggest that cool-adapted Andean Atelopus ancestors had dispersed into the Amazon basin and further onto the eastern Guiana Shield where, under warm conditions, they were forced to change climate envelopes. © 2010 The Author(s).
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
The aims of this study are to determine how anuran calling males are spatially and temporally distributed in the Morro do Diabo State Park (MDSP), and to test for indicator species in different breeding habitats. We found high species turnover among breeding habitats of different hydroperiods. Our results indicate that spatial partitioning is more important than seasonal occurrence in permitting species coexistence at MDSP. Indicator Species Analysis identified one species associated with a local stream, one species associated with permanent ponds, two species associated with temporary ponds, and three species associated with a semipermanent pond. Guilds of species do not appear to stratify their distributions throughout the year, since most species occur during the rainy and warm months and are thus temporally overlapping. The main conservation implication of our work is the need to protect the different areas of the park where these unique breeding habitats, and their associated anuran assemblages, are found.
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
The species belonging to the subfamily Phyllomedusinae presents physiological and behavioral adaptations to economise water such as secretion of lipids coupled with its spreading onto the skin surface through a complex behavior, adoption of diurnal torpor and secretion of uric acid. Here we describe other adaptation probably involved with water economy, registered in Phyllomedusa distincta, P. tarsius, P. tetraploidea and natural hybrids of P. distincta and P. tetraploidea - at dusk, these amphibians perform an elaborate moulting behavior that encompasses the cleaning of the body with the limbs plus gaping and body contractions. Our data show the daily moulting in P. distincta and suggest that the same mechanism occurs for the other species studied. We suppose that daily moulting improves the skin permeability to water being a characteristic of the phyllomedusines which spread lipids onto the skin surface.
Resumo:
Two new species of Gastrotheca are described from northeastern Minas Gerais and southern Bahia, in the Atlantic Forest of Brazil. Data on morphology, calls, mitochondrial, and nuclear DNA are provided. Allied to G. fissipes and G. megacephala, the new taxa provide evidence for a higher diversity of species of Gastrotheca than previously thought at the Atlantic Forest. The data also suggest that G. pulchra, another Atlantic Forest taxon, is more closely related to non-Atlantic Forest species than to the remaining analyzed Brazilian Gastrotheca species. This implies that the Gastrotheca at the Brazilian coastal forests have at least two independent origins.
Resumo:
Invasive species are known to affect native species in a variety of ways, but the effect of acoustic invaders has not been examined previously. We simulated an invasion of the acoustic niche by exposing calling native male white-banded tree frogs (Hypsiboas albomarginatus) to recorded invasive American bullfrog (Lithobates catesbeianus) calls. In response, tree frogs immediately shifted calls to significantly higher frequencies. In the post-stimulus period, they continued to use higher frequencies while also decreasing signal duration. Acoustic signals are the primary basis of mate selection in many anurans, suggesting that such changes could negatively affect the reproductive success of native species. The effects of bullfrog vocalizations on acoustic communities are expected to be especially severe due to their broad frequency band, which masks the calls of multiple species simultaneously.
Resumo:
Dietary data from a large sample of woodcreepers (16 spp., n?=?139), revealed that six species of dendrocolaptids occasionally feed upon lizards and frogs. These birds, which are mainly insectivorous, encounter and feed on lizards while perching on tree trunks, probably in association with army-ant swarm feeding behaviour. Frog intake may be related to declines in the abundance of invertebrate prey. The bones recovered were identified as one small species of gecko, Gonatodes humeralis, and at least one anuran. We estimate that in the entire sample, about eight lizards and two frogs were ingested. The partially digested gecko material allows determination of which bones are more resistant to digestion, although it is possible that these elements were differentially retained in the stomach. These elements correspond to the more frequently preserved bones in the fossil record of geckos, indicating that the same portions of the skeleton persist under the processes of both digestion and fossilization.
Resumo:
Documenting the Neotropical amphibian diversity has become a major challenge facing the threat of global climate change and the pace of environmental alteration. Recent molecular phylogenetic studies have revealed that the actual number of species in South American tropical forests is largely underestimated, but also that many lineages are millions of years old. The genera Phyzelaphryne (1 sp.) and Adelophryne (6 spp.), which compose the subfamily Phyzelaphryninae, include poorly documented, secretive, and minute frogs with an unusual distribution pattern that encompasses the biotic disjunction between Amazonia and the Atlantic forest. We generated >5.8 kb sequence data from six markers for all seven nominal species of the subfamily as well as for newly discovered populations in order to (1) test the monophyly of Phyzelaphryninae, Adelophryne and Phyzelaphryne, (2) estimate species diversity within the subfamily, and (3) investigate their historical biogeography and diversification. Phylogenetic reconstruction confirmed the monophyly of each group and revealed deep subdivisions within Adelophryne and Phyzelaphryne, with three major clades in Adelophryne located in northern Amazonia, northern Atlantic forest and southern Atlantic forest. Our results suggest that the actual number of species in Phyzelaphryninae is, at least, twice the currently recognized species diversity, with almost every geographically isolated population representing an anciently divergent candidate species. Such results highlight the challenges for conservation, especially in the northern Atlantic forest where it is still degraded at a fast pace. Molecular dating revealed that Phyzelaphryninae originated in Amazonia and dispersed during early Miocene to the Atlantic forest. The two Atlantic forest clades of Adelophryne started to diversify some 7 Ma minimum, while the northern Amazonian Adelophryne diversified much earlier, some 13 Ma minimum. This striking biogeographic pattern coincides with major events that have shaped the face of the South American continent, as we know it today. (C) 2012 Elsevier Inc. All rights reserved.