Ohio, Cumberland, and Tennessee River Systems

Volume 5 of the FWGNA series expands our continental survey of freshwater snails into the rivers, lakes, ponds, and streams of the Ohio drainage, together with its primary tributaries the Cumberland and the Tennessee. Our database of 9,370 records, sampled from approximately 4,250 distinct sites, was drawn from museums (24%), state natural resource agencies (34%) and personal collections. We document 80 species and 19 subspecies of freshwater gastropods in this malacologically rich region. For each we provide:

• A dichotomous key for identification.
• Full color figures.
• Range maps.
• Notes on habitat, ecology, and reproductive biology.
• Systematic and taxonomic updates to modern standards.

Our complete FWGNA database, updating records from Atlantic drainages and combining with our fresh data from the Interior, now contains 22,044 records documenting 107 species of freshwater gastropods, with 21 subspecies. Here we offer a new continent-scale biogeographic analysis, dividing records into North Atlantic, South Atlantic, Ohio, and Tennessee/Cumberland subsets. Our analysis suggests that natural selection has been more important in the evolution of freshwater pulmonate snails than gene flow restriction, but that gene flow restriction has been more important in the evolution of freshwater prosobranch snails than natural selection.

In Volume 1 we pioneered a new method to rank freshwater gastropods by incidence categories for the purposes of conservation, based on the work of K. J. Gaston. Here in Volume 5 we update that system to include all 107 species across all regions, re-assigning incidence ranks as necessary. Three new species of cave-dwelling hydrobioid snails: Fontigens hershleri, F. benfieldi, and F. davisi, are described in the appendix.

The Freshwater Gastropods of North America Project is a long term, collaborative effort to inventory and monograph the entire freshwater gastropod fauna of the continental United States and Canada. Born in the summer of 1998 at the world congress of Malacology in Washington, the effort has covered all or part of 17 eastern and southern states to date, extending from New York to Mississippi.  In Volume 1 of this series, we documented the distribution and abundance of 69 species inhabiting Atlantic drainages from Georgia to the New York line. Here in Volume 5 we expand our survey into the Ohio drainage, together with its primary tributaries the Cumberland and the Tennessee, a 203,000 square mile catchment touching all or part of 14 US states. 

Dr. Robert T. Dillon, Jr. is America's foremost authority on freshwater gastropods. From 1983 until his retirement in 2016 he was Professor of Biology at the College of Charleston in South Carolina. He is the author of The Ecology of Freshwater Molluscs (Cambridge University Press, 2000) and over 60 scientific papers on the genetics, evolution, and ecology of snails. A former president of the American Malacological Society, Dr. Dillon contributed the freshwater gastropod chapter to the popular 2006 AMS publication, The Mollusks: A Guide to their Study, Collection and Preservation. In 1998 he founded the Freshwater Gastropods of North America Project, authoring or coauthoring an extensive website, a popular blog, and seven hardcopy volumes to date.