Biotic exchanges between Neotropical biomes: evidence from the Bignoniaceae and other angiosperm clades

Abstract

The unequal distribution of taxa across the Globe has intrigued scientists for a long time. In particular, the observation that the Neotropics is more diverse than the Paleotropics has led ecologists, evolutionary biologists, systematists and biogeographers to search for explanations to this pattern for several hundred years. Indeed, few issues have been as exciting to scientists as the origin and evolution of the Neotropical Biota. Hypotheses such as the "cradle" and "museum" can help us understand the patterns of diversification in the Neotropics. These hypotheses can be explicitly tested through time-calibrated phylogenies of individual lineages. Such kinds of studies require detailed knowledge on the time of divergence of particular clades, which can be obtained by time calibrating existing phylogenetic frameworks. Despite the great benefits of using time-calibrated phylogenies for a better understanding of the biogeographical history of organisms and biotas, this is not a trivial task requiring a deep understanding of the fossil record. Few studies to date have used a comprehensive fossil record to time-calibrate phylogenies of different organisms. This project aims to carefully analyze the extensive fossil record of the plant family Bignoniaceae and to use this information as basis to time-calibrate an existing phylogenetic framework for the family. The time-calibrated phylogeny derived from this study will then be related to past geo-climatic events in order to test specific biogeographic hypothesis for the Bignoniaceae, a conspicuous component of the Neotropical Flora. The results derived from the Bignoniaceae will be subsequently combined with time-calibrated trees from many other angiosperm clades in order to obtain a more comprehensive picture of biotic exchanges across biomes, especially in what concerns biotic connections between Amazonia and the Atlantic forest. This project is part of the broader project "Structure and evolution of the Amazonian Biota and its environment: an integrative approach" (FAPESP 2012/50260-6) and "A multidisciplinary framework for biodiversity prediction in the Brazilian Atlantic forest hotspot (FAPESP 2013/50297-0). (AU)