Analysis of bat DNA published in Journal of Biogeography reveal that several neotropical species descended from ancestors that evolved in the West Indies, and this pattern is consistent with fossils found throughout the region. As the culmination in the study of several independent bat groups, this article shows that reverse colonization is a feature of the entire Caribbean bat community, encompassing groups of bats as different from each other as aerial insectivores, nectarivores, and frugivores.
The evolution of Caribbean bats suggests that far from being isolated destinations, the West Indies have had a dynamic, two-way relationship with the Americas, exchanging species back and forth at different points in their geological history. This discovery further enhances the conservation importance of the West Indies, where habitat loss and climate change —embodied in the intensification of hurricanes— threaten natural habitats more acutely than on the continent.
They did that with birds too. Makes you wonder if there weren't times in the past where islands were the isolating element and then when fortune, geology or climate intervened, terrestrial tetrapods were reintroduced to the mainlands, but changed.