A complex biogeographic history of diversification in Neotropical lancehead pitvipers, Bothrops (Serpentes, Viperidae)

We had predicted that the diversification within the Neotropical snake genus Bothrops occurred along a latitudinal gradient from north to south, with diversification into unoccupied niches through ecological opportunity, not correlated with geoclimatic events. Using a dated phylogeny and estimating likelihoods of ancestral states at cladogenesis events, we reconstructed ancestral areas and assessed the major events on the diversification of Bothrops clades. We infer that the diversification of the Miocene B. pictus and B. alternatus clades is related to the uplift of the western slopes of the Andes and the Argentinian Patagonia Mountains, respectively. The Pliocene B. taeniatus and B. osbornei clades is related to the uplift of the eastern and northern Andes, respectively. The Plio-Pleistocene B. neuwiedi clade is related to the habitat transitions from a warmer and forested environment to a cooler and open landscape; the B. jararaca and B. lanceolatus clades to over-water dispersal with island speciation; and the B. atrox clade to the appearance of the Panamanian land bridge. We found a multitemporal and multidirectional history of diversification being in part correlated with geoclimatic and dispersalist events. We argue that the vacant niche hypothesis by itself does not explain Bothrops diversification.