Unidirectional west-to-east trans-Andean dispersals characterize the biogeography of <i>Dracula</i> Luer (Pleurothallidinae-Orchidaceae)

Abstract We studied the biogeographical history of Dracula, an almost exclusive Andean genus of orchids. We built a phylogeny using the plastidial markers matK and ycf1 and nuclear ITS and used a combined approach of divergence time estimation and ancestral areas reconstruction. Thus, we aimed to clarify where and when the genus appeared and diversified, as well as how it colonized the Eastern and western Andean cordillera and expanded into Central and North America. Dracula originated in the Andes during the late Miocene, but its diversification was during the Pliocene and Pleistocene. The biogeographical history of the genus is marked by several independent events of peripheral isolation and dispersals. At least eight independent dispersal events occurred from the west to the east of the Andes, and none in the opposite direction. Colonization of Central and North America occurred at least three times independently. We conclude that based on our results Dracula has a recent and complex biogeographical history, where it could cross the Andes only in the west-to-east direction. Further investigation with expanded taxon sampling will be valuable to demonstrate whether this is a natural trend rather than an artefact of the available data.