JOHNSON, B. D.: The Phylogeography of the Western Hognose Snake

A large fragment of the mitochondrial ND2 gene was sequenced from a number of populations to assess the rangewide phylogeography of western hognose snakes, Heterodon nasicus. The resulting analyses designate Las Cruces, New Mexico, as representative of a deeply ancestral lineage and suggest an intriguing migratory history that identifies the most derived populations of H. nasicus as being located in Texas. If supported by further analysis, this unusual pattern may shed light on the post-glacial activity of H. nasicus (and perhaps other co-distributed species in the Great Plains) and the influence of geographic events on its life history. This project also detected evidence of a new species of Heterodon, a conclusion strongly supported by the molecular data and seemingly in accord with prior morphological work.