Species Composition and Geographic Distribution of Virginia\u27s Freshwater Gastropod Fauna: A Review Using Historical Records

Survey data from electronic databases and the literature were used to summarize knowledge of the composition and geographic distribution of Virginia\u27s freshwater gastropod fauna. After excluding records likely based on misidentifications, we concluded that 53 species of freshwater gastropods occur in Virginia now or historically. A map and/or narrative description of statewide distribution was produced for each species. Several species appeared to be restricted to a few sites and highly endangered, including the hydrobiids Fontigens bottimeri, Fontigens morrisoni, Holsingeria unthankensis, and Holsingeria sp. 1. Absence of recent records for the hydrobiid Sompatogyrus virginicus, the pomatiopsid Pomatiopsis cincinnatiensis, the pleurocerids Elimia archnoidea and Pleurocera gradata, and the lymnaeid Stagnicola neopalustris indicated these species might also be imperiled if not already extirpated from Virginia. Although we have a good understanding of distributions of Fontigens spp., Holdingeria spp., and of several river-dwelling pleurocerids in southwest Virginia, other species and geographic regions (e. g., eastern shore and Big Sandy River drainage) are undersurveyed. We provide data to assist in designing surveys to fill these knowledge gaps and to monitor temporal changes in species\u27 distributions. Comparisons of historic and future data from field surveys will facilitate protection and management of endangered species by providing evidence of restricted or shrinking geographic ranges