Sistemática e biogeografia do complexo de espécies Proceratophrys Cristiceps (anura, odontophrynidae)

Abstract

The Caatinga is a biome in northeastern Brazil characterized by deciduous xerophytic and thorny vegetation, and by a severe water deficit caused by intense and unpredictable dry seasons. Currently, the Caatinga harbors 56 species of amphibians. However, new species from this domain are being continuously described, including taxa restricted to rainforest natural enclaves (called “Brejos de altitude”), indicating that the richness of the region is still underestimated. The Proceratophrys genus is composed by 40 species, organized into morphological groups or complexes without phylogenetic support. Based on recent studies, we defined the complex P. cristiceps as the group including six species: P. cristiceps, P. minuta, P. redacta, P. schirchi, P. caramaschii and P. aridus. Herein, we evaluated the taxonomy, biogeography, and evolution of the species related to the P. cristiceps complex, combining morphologic, morphometric and acoustic characteristics, and molecular multilocus analyses. Our results, based on these integrative analyses, show P. aridus, P. caramaschii and P. cristiceps as belonging to the same lineage, without morphologic or acoustic distinction. Thus, we place the first two species as junior synonyms of P. cristiceps. We also found one population from Chapada do Araripe, previously called P. cristiceps, related to the Amazonian species P. concavitympanum, that we described as a new species. We considered this new species as Endangered based on IUCN criteria, once it occurs in a small area (ca. 3.100 km2 ), severely impacted by deforestation and canalization of local streams for agriculture and recreational use. Next, we revised Proceratophrys populations from higher elevations in the Chapada Diamantina and described two new species based on morphology and phylogenetic relationships (we used one mitochondrial and one nuclear marker). We found that each lineage from the Chapada Diamantina corresponds to a specific mountain block, each separated by warmer and more xeric valleys, which may act as barriers to gene flow, promoting allopatric diversification. Therefore, we considered each one as distinct species, except the Pindobaçu population, which requires further analyses (more individuals and molecular markers) to define more precisely its taxonomic status. Finally, we conducted a multilocus phylogeographic analysis to evaluate the genetic diversity, geographic structure and demography history of P. cristiceps. We recovered P. cristiceps as one single population widely distributed in the Caatinga, with low levels of haplotype diversity for 16S mtDNA and CRYb, POMC, and rhodopsin nuDNAs. Our results indicate that P. cristiceps effective population size varied, with a rapid and recent expansion throughout the upper Pleistocene.