Format: ORAL

Francisco Fajardo-Gutirrez1,2,8, Christine Edwards3, J. Sebastian Tello3, Alfredo Fuentes3,4, Nora H. Oleas5, Ricardo A. Segovia6, Mariasole Calbi7, Markus Dillenberger1,8, James E. Richardson9Yohan Pillon10and Thomas Borsch1,8

1 Botanischer Garten und Botanisches Museum Berlin-Dahlem. Berlin, Germany 2 Jardín Botánico de Bogotá José Celestino Mutis, Bogotá, Colombia 3 Missouri Botanical Garden, St. Louis, USA 4 Universidad Mayor de San Andrés, La Paz, Bolivia 5 Universidad Tecnológica Indoamérica, Ambato, Ecuador 6 Universidad de Concepción, Concepción, Chile 7 University of Genoa, Genoa, Italy 8 Freie Universität Berlin, Berlin, Germany 9 University College Cork, Cork, Ireland 10 Université Montpellier, Montpellier, France

Cunoniaceae, mostly distributed in the Southern hemisphere, comprises 27 genera and c. 335 species. The highest diversity can be found in New Caledonia and South America. Also, diversity is concentrated in the genusWeinmannia(c. 80 species), which is dominant in cloud and montane forests along the Andes. Other ten to fifteenWeinmanniaspecies are scattered throughout the Americas in the Atlantic Forest (South Brazil), the Guyana shield, Central America, Mexico, and the Caribbean islands. Our main objective is to reveal the phylogeographic history and diversification patterns of the group. We used a relaxed molecular clock, based on DNA sequences of three plastid markerstrnK-matK,trnL-trnF, andrps3-rpl16, and twelve fossil calibrations, with an extended sampling across the Rosid lineages. We found the Cunonieae tribe (Cunonia,Pancheria,PterophyllaandWeinmannia) diverging during the late Eocene (~39.6 Ma), and the estimated age ofWeinmannia(~34 Ma), correspond with the age of the Eocene-Oligocene Transition (33.9 Ma). This transition was characterized by the first formation of the Antarctic ice sheet and the isolation of the Gondwanan groups caused by the opening of the Drake Passage betweenSouth America and Antarctica, and the Tasman Seaway between Australia and Antarctica. Such continental rearrangement explains the current distribution of the taxa in the tribe. The most basal species ofWeinmanniaare in the Mascarenes Islands and Chile, while the central and northern Andean species show a recent evolutionary radiation estimated to have occurred ~5.5 Ma, which is consistent with the two major pulses of Andean uplift during the Miocene and Pliocene at c.126 Ma and c. 4.5 Ma.Our results support the idea that continental drift and orogeny played a crucial role in determining the distribution and diversification ofWeinmannia.