From Patagonia to Central America, an evolutionary history of Dysopsis (Euphorbiaceae)

Distribution of the South American flora, especially along the Andes, reveals patterns related to geological and climatic events. In this study, we investigate the evolutionary and biogeographic history of Dysopsis (Euphorbiaceae), a genus of small herbs distributed in cool, moist habitats from southern Chile to Costa Rica. Phylogenetic analyses using one nuclear and three plastid DNA markers show that the genus is monophyletic and consists of four species. The relationships of Dysopsis with other genera in the subfamily Acalyphoideae show the closest ties to Adelia, Caperonia, Ditaxis, Lasiocroton, Leucocroton, and Philyra. Divergence analysis reveals that Dysopsis arose in the Austral Andes in the Middle Miocene and later colonized northern environments. This colonization was facilitated by uplift of the Andes between the Late Miocene and Early Pleistocene, and also by different periods of glaciation and interglaciation, with Dysopsis maintaining its general ecological tolerances during these transitions. Divergence within the genus was stimulated by vicariant events in Patagonia and the Central Andes and by dispersal from the continent to the Juan Fernández archipelago.