Diversification of North American natricine snakes

Abstract

The phylogeny of thamnophiine snakes has not been fully resolved, largely because previous phylogenetic estimates have been based on incomplete taxon sampling or relied solely on mitochondrial sequence data. To address this deficiency, we collected data from multiple autosomal loci collected from 50 taxa before estimating the most robust phylogeny of Thamnophiini to date. Our findings clarify the relationships of taxa not previously included in molecular analyses and also lend evidence to previously recommended taxonomic revisions. Differences in topological estimates between competing models of evolution were minimal and not strongly supported; however, a multispecies coalescent model of evolution was highly favoured over a concatenated model based on marginal likelihood estimates. Additionally, we estimated the timing of divergence among the three major lineages to have occurred during the Miocene period (approximately 11–14 Mya), followed by a decline in speciation rates in all major lineages.