Recent lineage diversification in a venomous snake through dispersal across the Amazon River
Journal
Biological Journal of the Linnean Society
Date Issued
2018
Author(s)
Gibbs H.L.
Sovic M.
Amazonas D.
Chalkidis H.
Moura-Da-Silva A.M.
Type
Article
Abstract
Identifying the evolutionary and ecological mechanisms that drive lineage diversification in the species-rich tropics is of broad interest to evolutionary biologists. Here, we use phylogeographical and demographic analyses of genomescale RADseq data to assess the impact of a large geographical feature, the Amazon River, on lineage formation in a venomous pitviper, Bothrops atrox. We compared genetic differentiation in samples from four sites near Santarem, Brazil, that spanned the Amazon and represented major habitat types. A species delimitation analysis identified each population as a distinct evolutionary lineage while a species tree analysis with populations as taxa revealed a phylogenetic tree consistent with dispersal across the Amazon from north to south. Phylogenetic analyses of mitochondrial DNA variation confirmed this pattern and suggest that all lineages originated during the mid- to late Pleistocene. Historical demographic analyses support a population model of lineage formation through isolation between lineages with low ongoing migration between large populations and reject a model of differentiation through isolation by distance alone. The results provide a rare example of a phylogeographical pattern demonstrating dispersal over evolutionary timescales across a large tropical river and suggest a role for the Amazon River as a driver of in situ divergence both by impeding (but not preventing) gene flow and through parapatric differentiation along an ecological gradient. © 2018 The Linnean Society of London, Biological Journal of the Linnean Society.
Subjects