Biogeography and divergence time estimates of woody bamboos: insights in the evolution of Neotropical bamboos

Abstract

The Neotropical woody bamboos are a monophyletic lineage with three subtribes in the Bambusoideae: Arthrostylidiinae, Chusqueinae and Guaduainae. The geographical distribution of these subtribes extends from Mexico, Central America, Caribbean Islands, to South America. In order to understand the biogeographical patterns and origin of these bamboos, a phylogeny of Neotropical woody bamboos was first inferred. Then divergence time estimation of particular nodes using a Bayesian approach and ancestral area reconstruction using S-DIVA were performed. The results suggest a Miocene origin of Neotropical bamboos where the subtribe Chusqueinae was the oldest, followed by the Arthrostylidiinae and the Guaduinae. The ancestral area reconstruction indicated a complex scenario in which the ancestral area for Chusqueinae was Andean South America followed by multiple dispersal events to Atlantic Brazil and Mesoamerica. Overall, the results support the hypothesis of a South American origin of the Neotropical woody bamboos, corroborated by the molecular dating, ancestral area reconstruction and the fossil record.