Phylogeny and historical biogeography of the Neotropical genus Besleria (Gesneriaceae)

Abstract

Besleria L. is a Neotropical genus of perennial herbs, shrubs or small tree growing in the understory of rainforests. With over 165 species Besleria is the second largest genus of the New World Gesneriaceae. Taxonomy and evolution of Besleria has been little explored in molecular phylogenetic studies. Here, we estimated the phylogeny of Besleria including about 50% of the recognized species using nuclear and platidial regions (ITS, matK, rps16 and trnL-trnF) and two secondary calibrations points to estimate divergence times. We used this phylogeny to revise the classification and biogeographic history of the genus. Our phylogenetic analyses support the monophyly of Besleria and its sister relationship with Cremosperma. Five major clades were resolved within the genus that do not correspond with the sections and subsections currently recognized for the genus. Clades are better characterized by their distribution pattern rather than morphological synapomorphies. Biogeographic reconstruction indicates that Besleria originated in northern Andes during the Middle Miocene (ca. 15 Mya). Geological and climatic events related to the Andes uplift and Panama Isthmus formation explain the current distribution patterns and help to clarify the biogeographic history of the group.