Assessment of Genetic Diversity in the Western Shovel-Nosed Snake (Chionactis occipitalis), with Special Emphasis on the Subspecific Status of the Tucson Shovel-Nosed Snake (C. o. klauberi)

摘要

We examined the phylogeography, population structure, and subspecies taxonomy of the western shovel-nosed snake (Chionactis occipitalis) across its geographic range with genetic analysis of approximately 1100 bases of ND1 mitochondrial DNA sequence. A phylogeny was reconstructed from 81 snakes using maximum parsimony and Bayesian methods, and nested cladistic phylogeographical analysis was used to help discriminate between evolutionary processes operating at the population level. The phylogeny reveals significant geographical structuring of haplotypes and two distinct regional lineages (West Mojave and Sonoran/East Mojave). Diversification between these lineages appears to have developed as a result of vicariance. In addition, patterns of isolation by distance, suggesting reduced gene flow, occur throughout regions of each lineage and have contributed to the population structure among collection localities.