Meeting Abstract

P2.212  Saturday, Jan. 5  Cryptic genetic diversity and refugial dynamics in the flathead snake COX, CL*; STRINGER, JF; STREICHER, JW; MOSELEY, MA; CHIPPINDALE, PT; University of Virginia; The University of Texas-Arlington; The University of Texas-Arlington; The University of Texas-Arlington; The University of Texas-Arlington clcox@virginia.edu

Determining the role of geography in structuring phylogenetic relationships within species can be useful for inferring biogeography, detecting cryptic genetic diversity, and revising species boundaries within a clade. However, broad inferences about how geography influences genetic diversity and speciation can be limited by the taxonomic breadth of phylogeographic studies. For many groups of vertebrates (especially small and cryptic species) these phylogenetic relationships are not well understood. We assessed the genetic relationships among populations of the small and cryptic flathead snake (Tantilla gracilis) by sequencing the mitochondrial genes of ND4 and cytb (total of ~1200 bp) for over 70 snakes from across their geographic range. Phylogenetic relationships were analyzed using maximum parsimony, maximum likelihood and Bayesian inference. We found substantial phylogenetic structure within the flathead snake, with geographically consistent western and eastern clades separated by approximately 2% sequence divergence. Additionally, we found multiple well-supported and geographically restricted clades in south Texas, central Texas and Louisiana. These results highlight cryptic genetic diversity within flathead snakes and suggest a pattern of historical glacial refugia and range expansion. Our findings of cryptic phylogenetic structure in flathead snakes in a geographically homogenous area highlight the importance of taxonomic diversity in phylogeographic research.