The Radiation of New World Pitvipers: A Macroevolutionary Perspective

Alencar, Laura R.V. alencarlrv@gmail.com

Department of Ecology

University of São Paulo

São Paulo, Brazil

The arrival of a lineage in a continent can spur rapid species formation. Distinct evolutionary processes could potentially underlie this increase in speciation rates. Moreover, given that ecological and environmental variables vary among different regions, once a lineage expands and diversifies through a large continental area, the diversification dynamics characterizing this radiation could differ in the different parts of the continent. Although vipers originated in the Old World, members of the subfamily Crotalinae (pitvipers) arrived in the New World ~26 million years ago, greatly diversifying throughout the region. In the present talk, I will briefly review what we know about the evolutionary history of the New World radiation of pitvipers, focusing on biogeographic and macroevolutionary aspects. I will also show some results from a very recent study where I am exploring (1) the possible processes underlying the rapid pitviper diversification in the New World; (2) how the climatic and ecological niche changed during the radiation and in the distinct regions of the American continent; (3) if the distinct evolutionary trajectories of those niche axes resulted in different patterns shown by the extant New World pitviper species.