Phylogenetic relationships and population differentiation of Oreohelix landsnails in Wyoming and adjacent South Dakota

Over 50% of terrestrial snails and slugs species in the Order Stylommatophora are endangered or already extinct. In Wyoming, three of the five surveyed Oreohelix landsnail species are included in the list of Wyoming species of greatest conservation need. In particular, Oreohelix strigosa cooperi from the Black Hills National Forest (BHNF) of South Dakota and Wyoming has drawn recent conservation attention because of a petition to list it under the Endangered Species Act. Based on differences in shell size and sculpture, some researchers proposed that the forms of Oreohelix in the Black Hills constitute three distinct species. But a recent genetic study found that the three forms show little genetic divergence at two mitochondrial genes. Genetic differentiation at nuclear loci has not been studied, and might reveal signals that differ from those produced by the mitochondrial genome.; Here, I used a nuclear marker, amplified fragment length polymorphism (AFLP), to study the genetic distinctiveness and population differentiation of O. strigosa cooperi. I found that O. strigosa cooperi in the BHNF was genetically distinct from other Oreohelix snails in Wyoming, particularly O. pygmaea in the Big Horn Mountains and O. subrudis that are widespread in Wyoming. I found strong genetic differentiation between O. strigosa cooperi from the Bear Lodge Mountains (WY) and the Black Hills (SD). Oreohelix from the Bear Lodge Mountains were reciprocally monophyletic with respect to those from the Black Hills. However, I found low genetic differentiation within the Black Hills. Large- and small-bodied populations of O. strigosa cooperi, which have been proposed as distinct at the species level, could not be distinguished genetically. Management implications of this study include the suggestion that, at least from a genetic perspective, populations of O. strigosa cooperi from the Bear Lodge and Black Hills should be managed separately, and that all forms within the Black Hills should be managed together. Future research should focus on building a complete molecular phylogeny of the Oreohelix genus to improve the current classification, and focus on experimentally studying the factors that control shell morphology in the Black Hills Oreohelix .