Neotropical Snakes Reveal Different Geological Times for Dispersal Corridors Between Amazon and Atlantic Forests

ABSTRACT Three forested dispersal corridors have been proposed within the diagonal of open/dry landscapes in South America and the relative importance of each one has been the subject of debate for forest organisms. We analysed the biogeographical history of three snake genera ( Bothrops , Philodryas , and Micrurus ) from different families (Viperidae, Dipsadidae, and Elapidae, respectively) to test the corridors' importance. We reconstructed the biogeographical history of the groups by Maximum Likelihood models and implemented Biogeographical Stochastic Mapping (BSM) to analyse the average number and the mean ages of dispersals through each corridor. The statistical significance of dispersal ages was tested via Wilcoxon‐Mann–Whitney tests. The Central corridors presented the highest average number of dispersals for all groups combined, as well as for Micrurus and Philodryas genera. However, the Eastern corridor was more important for the Bothrops genus. Most dispersals in the Western corridor are likely to have been older than the other two, prior to the Pliocene. Dispersals in the other corridors likely occurred mostly during the Pliocene. Our results do not support the hypothesis of terrestrial vertebrates dispersing mainly through the Western corridor. We reinforce the importance of incorporating the time dimension in biogeographical studies, as dispersal ages varied among the three corridors.