Phylogeography and historical demography of the arboreal pit viper Bothrops bilineatus (Serpentes, Crotalinae) reveal multiple connections between Amazonian and Atlantic rain forests

Abstract

Aim To examine historical connections between rain forest habitats in the Neotropics based on the evolutionary history of the arboreal pit viper Bothrops bilineatus. Location Amazonia and Atlantic Forest in South America. Methods We inferred phylogenetic relationships within Bothrops and phylogeographic relationships within B. bilineatus using both concatenated and species tree approaches under a Bayesian framework based on four mitochondrial and five nuclear genes. We inferred demographic history within B. bilineatus based on tests of alternative historical scenarios using coalescent simulations and Approximate Bayesian Computation. Results Phylogenetic analyses recovered four major clades within Bothrops bilineatus. The best-fit historical scenario involved colonization of the Atlantic Forest by an Amazonian ancestor around 2 Mya, followed by range expansion in the Atlantic Forest. Subsequently, there was a colonization event into the Guiana Shield from an Atlantic Forest ancestor, dating back to around 0.3 Mya. Main conclusion The complex demographic history of Bothrops bilineatus shows multiple connection events between Amazonia and the Atlantic Forest in the last 2 million years. Two previously hypothesized forest bridges, southern and northeastern, may have been involved in range expansions in this species. These results shed light on the historical processes involved in the diversification of this venomous South American snake, providing information about the historical dynamism of forested habitats in the Neotropics.