Neotropics as a Cradle for Adaptive Radiations
Neotropical ecosystems are renowned for numerous examples of adaptive radiation in both plants and animals resulting in high levels of biodiversity and endemism. However, we still lack a comprehensive review of the abiotic and biotic factors that contribute to these adaptive radiations. To fill this gap, we delve into the geological history of the region, including the role of tectonic events such as the Andean uplift, the formation of the Isthmus of Panama, and the emergence of the Guiana and Brazilian Shields. We also explore the role of ecological opportunities created by the emergence of new habitats, as well as the role of key innovations, such as novel feeding strategies or reproductive mechanisms. We discuss different examples of adaptive radiation, including classic ones like Darwin’s finches and Anolis lizards, and more recent ones like bromeliads and lupines. Finally, we propose new examples of adaptive radiations mediated by ecological interactions in their geological context. By doing so, we provide insights into the complex interplay of factors that contributed to the remarkable diversity of life in the Neotropics and highlight the importance of this region in understanding the origins of biodiversity.
Short‐faced bats (Phyllostomidae: Stenodermatina): a Caribbean radiation of strict frugivores
Aim To test the hypothesis that Caribbean Short‐faced bats descended from a single recent ancestor that originated in the continental Neotropics (Mexico, Central America and/or South America). Location The Neotropics, including the West Indies. Methods New mitochondrial cytochrome b and nuclear Rag2 sequences were combined with published molecular data to estimate phylogenetic relationships and sequence divergence among Short‐faced bats. The resulting phylogenies were compared with those compatible with the single‐origin hypothesis using two model‐based statistical tests. Confidence limits on sequence divergence were estimated using a parametric bootstrap. Results All molecular phylogenies revealed two independent Caribbean lineages and showed that continental Short‐faced bats share a recent common ancestor. Morphology‐based trees compatible with the single‐origin hypothesis were significantly worse at explaining the molecular data than any molecular phylogeny. Main conclusions The ancestor of all Short‐faced bats reached the Antilles in the Miocene, too recently to have used a proposed Oligocene land bridge, and well before the Pleistocene glaciations that are thought to have facilitated dispersal for many bats. After a long period of isolation, Short‐faced bats diversified quickly on the Caribbean islands. A single Short‐faced lineage then reached the continent and subsequently expanded its range and diversified into the four extant genera. Among bats, independent lineages of aerial insectivores and nectarivores have also recolonized the continent after evolving in the West Indies. The evidence for an insular origin of the short‐faced frugivorous radiation completes a dynamic model of Caribbean biogeography that encompasses an entire biological community.