Phylogenetics, character evolution, and historical biogeography of the Neotropical genus Besleria (Gesneriaceae).

This article focuses on the phylogenetic relationships, morphological evolution, and biogeographical history of Besleria, a large neotropical genus of perennial herbs, shrubs, and small trees within the Gesneriaceae family, comprising over 165 species. Using DNA sequence data from nuclear and chloroplast regions covering about half of the species, the study confirms the monophyly of Besleria and identifies six major clades with distinct geographic distributions, none of which correspond to previous morphological classifications. Divergence time estimates suggest Besleria originated in the northern Andes during the Middle Miocene (~19 million years ago), with subsequent diversification shaped by geological events such as Andean uplift and the formation of the Panama Isthmus, influencing dispersal into Central and South America, the Brazilian Atlantic Forest, and the West Indies. Morphological traits traditionally used for classification show high convergence and limited phylogenetic signal, indicating the need for revised taxonomic frameworks supported by molecular data.