Diversidade genética em um grupo de anuros em miniatura endêmico da Mata Atlântica brasileira (Euparkerella Griffiths 1959).

Abstract

The Atlantic Forest (AF) is among the regions with the greatest and most threatened biodiversity in the planet. Efforts have been made in various areas of knowledge in order to get a more refined estimate of diversity and its organization throughout the biome. The growing number of studies that attempt to reconstruct the history of diversification of AF suggest a scenario spatially and temporally complex. Nevertheless, there is still a gap in the knowledge of processes on a small scale. Miniature vertebrates have been a good tool for studies of evolutionary processes on a small scale. Thus, the genus Euparkerella, endemic to a small region of the MA of the States of Rio de Janeiro (RJ) and Espírito Santo (ES), was chosen as the model for this study. In the first chapter we sought to describe the diversity within the genus through a molecular phylogeny. For this reason, we used Bayesian methods to generate genes and species genealogies trough one fragment of mitochondrial gene and four fragments of nuclear genes. The results pointed to a great cryptic diversity in the genus. We identified six evolutionary units significantly divergent for RJ: two in Euparkerella cochranae, three in Euparkerella brasiliensis, and Euparkerella sp.. The most basal species recovered was Euparkerella robusta, from ES. We estimated the early diversification of the genus to the end of the Miocene. The second chapter describes eleven microsatellite markers developed for Euparkerella brasiliensis through the method of next generation 454 pyrosequencing. In the third chapter we studied only one evolutionary unit, Euparkerella brasiliensis from Três Picos/ RJ. Trough markers of fast (microsatellites) and slow (DNA sequences) evolution we sought to understand the population s structure and dynamics of this evolutionary unit in a very small area (approx. 20 km) under the influence of an altitudinal environmental gradient (40 m - 1000 m). We identified through microsatellites two subpopulations genetically distinct on edges of the gradient. The gene flow occurred predominantly from the edges to the contact zone, where we observed the largest effective population size. These results indicate that small environmental changes can promote isolation in Euparkerella and corroborate the pattern of microendemic forms identified in the phylogeny. Future studies should be made to characterize morphologically the evolutionary units identified herein; fill gaps sampling, especially in ES, and describe the processes that operate on a small scale in the contact zones between the evolutionary units and factors that delimit their distribution.