Phylogeography of the greater short-horned lizard (phrynosoma hernandesi) in Alberta

Abstract

The distribution pattern of a species reflects a mixture of historic and present-day influences. In Alberta, the Greater Short-homed lizard reaches the northern edge of its range and exhibits a patchy distribution pattern. Many sites where it occurs appear to be isolated. Phylogenetic inference and population genetics were employed to investigate the historical source(s) of the Alberta representatives and to determine whether Alberta "populations" are subject to gene flow between them. Two mitochondrial DNA genes and one nuclear DNA gene were sequenced from 94 lizard tail-tips collected from twelve localities in Alberta. Overall, Alberta lizard sequences displayed very little variability, and genetic analyses revealed that the most parsimonious explanation is that this species in Alberta is descended from one source population. All localities are inferred to be historically genetically interconnected. The correlation of homed lizard localities with selected landscape features revealed that they occupy only small portions of seemingly much more extensive suitable habitat. Overall, the historic genetic information investigated, and particular features of the landscape failed to explain the species' present-day distribution patterns in southeastern Alberta.