Barriers, rather than refugia, underlie the origin of diversity in toads endemic to the Brazilian Atlantic Forest

In this study, we investigated the relative contribution of geographic barriers and Pleistocene refuges in the diversification of the Rhinella crucifer species complex, a group of endemic toads with a widespread distribution in the Brazilian Atlantic Forest (AF). We used intensive sampling and multilocus DNA sequence data to compare nucleotide diversity between refuge and nonrefuge areas, investigate regional demographic patterns, estimate demographic parameters related to genetic breaks and test refuge versus barrier scenarios of diversification using approximate Bayesian computation. We did not find higher levels of genetic diversity in putative refuge areas, either at regional or biome scale. Rather, the demographic history of the species complex supports regional differences with moderate population growth in the north and central regions and stability in southern AF. Genetic breaks were dated to the Plio–Pleistocene; however, our analyses rejected the role of refuges in creating a ...