> Habitat & Distribution

Van der Schalie & Dundee (1955) gave the range of P. cincinnatiensis as extending from Iowa through five states of the Ohio and Great Lakes drainages to southwest Virginia.  We have records from the muddy banks of rivers throughout the Ohio River drainage, including the Tennessee/Cumberland, from northern Indiana through Ohio to West Virginia and East Tennessee, south to North Alabama.  Populations seem to reach maximum abundance a meter or two above current river levels; we very rarely see individual Pomatiopsis actually in contact with the water itself.  FWGNA incidence rank I-4.

Pomatiopsid snails are amphibious.  Van der Schalie & Dundee observed,  "P. cincinnatiensis seems to require a creek or a river where the mud or matted root system on which the animals live retains a considerable amount of moisture.  Consequently, the area inhabited by these snails is a more or less narrow linear zone.  It appears to be governed by the amount of moisture the banks retain."

> Ecology & Life History

Sexes are separate and in the Pomatiopsidae, females maturing at a larger size than males and comprising a greater proportion of the population (van der Schalie & Getz 1962).  Eggs are laid singly in firm mud or soil (van der Schalie & Walter 1957).  A simple annual life cycle (Life cycle A of Dillon 2000: 156-162) seems to be typical for P. cincinnatiensis populations (van der Schalie & Getz 1962).

North American Pomatiopsis is biologically similar to Oncomelania, the host of schistosomiasis in the Orient (Abbott 1948), and hybridization has been reported in the laboratory (van der Schalie et al 1962).  See Van der Schalie & Getz (1963) for experiments comparing the temperature and moisture requirements of P. cincinnatiensis, P. lapidaria, and four species of Oncomelania.

> Taxonomy & Systematics

The genus Pomatiopsis was placed in the family Hydrobiidae until split, together with seven other genera from four other continents, into a separate family Pomatiopsidae by Davis (1979). This judgement was confirmed by the sequencing results of Wilke and colleagues (2001, 2013).

The species-level taxonomy of the North American taxa seems to have remained stable for quite a few years.  See Berry (1943) for a review of the anatomy of P. cincinnatiensis.

> Maps and Supplementary Resources 

• Pomatiopsis in the drainage of The Ohio (2019)
• Pomatiopsis in the Tennessee/Cumberland (2022)

> References

Abbott, R. (1948) Handbook of medically important mollusks in the Orient and the western Pacific. Bulletin of the Museum of Comparative Zoology, Harvard, 100:269-328.
Berry, E. G. (1943)  The Amnicolidae of Michigan: Distribution, ecology, and taxonomy. Misc. Publ. Mus. Zool. Univ. Mich. 57: 1 - 68. 
Clarke, A.H. (1981)  The Freshwater Mollusks of Canada. National Museums of Canada, Ottawa, Ontario, Canada. 
Davis, G. (1967) The systematic relationship of Pomatiopsis lapidaria and Oncomelania hupensis formosana (Prosobranchia: Hydrobiidae). Malacologia, 6:1-143. 
Davis, G. (1979)  The origin and evolution of the gastropod family Pomatiopsidae, with emphasis on the Mekong River Triculinae. Academy of Natural Sciences of Philadelphia Monographs, 20: 1-120.
DeWitt, W. B. (1952) Pomatiopsis lapidaria, its occurrence in the Washington, D.C., area and its laboratory rearing in comparison to that of Oncomelania spp.   J. Parasit. 38: 321-326. 
Dillon, R.T., Jr. (2000) The Ecology of Freshwater Molluscs. Cambridge University Press, Cambridge, United Kingdom. 
Hubricht, L. (1960) Pomatiopsis lapidaria on the southern Atlantic coastal plain, with remarks on the status of P. praelonga and P. hinkleyi. Nautilus, 74:33-34. 
Jokinen, E.H. (1992) The freshwater snails of New York State. New York State Museum Biological Survey, New York State Museum Bulletin 482.   
Stewart, T. (2006) The freshwater gastropods of Iowa (1821-1998): Species composition, geographic distributions, and conservation concerns. Amer. Malac. Bull., 21:59 - 75.  
Stewart, T. W., & R. T. Dillon, Jr.  (2004)  Species composition and geographic distribution of Virginia's freshwater gastropod fauna: A review using historical records.  Am. Malac. Bull. 19: 79-91.
van der Schalie, H. & Dundee, D. S. (1955)  The distribution, ecology, and life history of Pomatiopsis cincinnatiensis (Lea), an amphibious, operculate snail.  Trans. Am. Microscop. Soc. 74: 119-133.
van der Schalie, H. & Getz, L. (1962)  Distribution and natural history of the snail Pomatiopsis cincinnatiensis (Lea). Am. Midl. Nat., 68:203-231.
van der Schalie, H. & Getz, L. (1963)  Comparison of temperature and moisture responses of the snail genera Pomatiopsis and Oncomelania.  Ecology 44: 73-83.
van der Schalie, H., Getz, J. & Dazo, B. (1962) Hybrids between American Pomatiopsis and oriental Oncomelania snails. Am. J. Trop. Med. Hyg., 11:418-420.  
van der Schalie, H. & Walter, H. (1957) The egg-laying habits of Pomatiopsis cincinnatiensis (Lea). Transactions of the American Microscopical Society, 76:404-422.   
Wilke, T., Davis, G., Falniowski, A., Giusti, F., Bodon, M. & Szarowska, M. (2001) Molecular systematics of Hydrobiidae (Mollusca: Gastropoda: Rissooidea): testing monophyly and phylogenetic relationships. Proceedings of the Academy of Natural Sciences of Philadelphia, 151:1-21.
Wilke T., Haase M., Hershler R., Liu H-P., Misof B., Ponder W. (2013)  Pushing short DNA fragments to the limit: Phylogenetic relationships of “hydrobioid” gastropods (Caenogastropoda: Rissooidea).  Molecular Phylogenetics and Evolution 66: 715 – 736.
Wojdak, J.M. & G.G. Mittelbach (2007)  Consequences of niche overlap for ecosystem functioning: an experimental test with pond grazers. Zool. Univ. Mich., 417: 1-21. 
Wu, S.-K., Oesch, R. & Gordon, M. (1997) Missouri Aquatic Snails. Missouri Department of Conservation, Jefferson City.