Phylogeny of Weinmannia (Cunoniaceae) reveals the Contribution of the Southern Extratropics to Tropical Andean Biodiversity.

The Andes are a relatively young mountain range with an impressive concentration of biodiversity. The biogeographic processes contributing to the hyperdiversity of the tropical Andes are still being unraveled. Novel mid- to high-elevation climates may have served as a biological corridor for the immigration of temperate-adapted lineages to lower latitudes, contributing unknown levels of diversity to this region. We tested the hypothesis that the genus Weinmannia corresponds to a lineage of extratropical origin that recently reached and then diversified extensively in tropical Andes. Using a 2bRAD seq approach to generate a time-calibrated phylogenetic tree for the genus, we found that the earliest diverging clades represent southern extratropical species, and a tendency for younger clades to be distributed towards northern latitudes. These results suggest a dispersal route for Weinmannia from the southern extratropics to the tropical Andes. As remnants of these lineages of southern origin converge with those that originated in other tropical and extratropical centers of diversification, we provide insights into the multisource origins of hyperdiversity in the modern montane forests of the tropical Andes.