Format: ORAL

Federico Fabriani 1 Francis J. Nge 2 Vincent R.C. Soul 2 Carlos Rodrigues-Vaz 2 3 Thomas L.P. Couvreur 2 Lars W. Chatrou 1

1 Ghent University, Ghent, Belgium 2 DIADE, Univ. Montpellier, CIRAD, IRD, Montpellier, France 3 Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d'Histoire Naturelle, Paris, France

The genus Duguetia (Annonaceae) is composed of 97 species of trees found mostly in tropical America with the Amazon basin representing the main centre of diversity for the genus. Some species occur in the Atlantic coastal forest, Central America and South American savannahs. Although the Amazon basin is the world largest tropical forest hosting an estimated tree flora between 9 and 16 thousand species, drivers and dynamics of tree species diversification are not yet fully understood. Previous studies have showed that Duguetia started diversifying during the Eocene, probably within the Amazon basin. Additionally, Duguetia species are present in virtually all vegetation types found in the Amazon. These characteristics make Duguetia an outstanding example to study the diversification and biogeography of Amazonian trees. We produced a genomic dataset with near-full taxon sampling, based on low copy nuclear genes, to infer species relationships. Consequently, we were able to infer a fully resolved and strongly supported species-level phylogenetic tree which we used in conjunction with a selection of morphological and biogeographical characters to reconstruct the historical biogeography and investigate possible drivers of diversification in Duguetia. Our results show that the genus Duguetia likely originated in Africa, and diversified in the Amazon basin with a few independent range expansions into the Atlantic forest and Central America. We hypothesize that a combination of characters within a particular vegetation type, rather than single characters, has led to accelerated diversification rates. Our results contribute to an improved understanding of the origin and diversification dynamics of the Amazonian tree flora.