Tulotoma Snail

Tulotoma magnifica

Description

Tulotoma is a gill-breathing, operculate snail. Its shell is globular, reaching a size somewhat larger than a golf ball, and typically ornamented with spiral lines of knob-like structures. Its adult size and ornamentation distinguish it from all other freshwater snails in the Coosa-Alabama River system. Tulotoma is also distinguished by its oblique aperture with a concave margin.

Behavior

The tulotoma snail broods young and filter-feeds, as do other members of the Viviparidae.

Habitat

The tulotoma snail occurs in cool, well-oxygenated, clean, free-flowing waters, with the habitat including both the mainstem river and the lower portions of large tributaries. This species is found in riffles and shoals and has been collected by U.S.Fish and Wildlife Service (FWS) divers at depths of more than 15 ft (4.5 m) with strong currents. The species is strongly associated with boulder/cobble substrates and is generally found during daylight hours clinging tightly to the underside of large rocks. Other aspects of its biology are virtually unknown.

Distribution

The historic range of the tulotoma snail was from the Coosa River in St. Clair County, Alabama, to the Alabama River in Clarke and Monroe Counties, Alabama. Historic collecting localities in the Coosa River System included numerous sites on the river as well as the lower reaches of several large tributaries. This snail has only been recorded from two localities in the Alabama River System: the type locality near Claiborne, Monroe County, Alabama, and Chilachee Creek southwest of Selma, Dallas County, Alabama. Other than isolated archaeological relics, the species has never been recorded from the Tombigbee, Black Warrior, Cahaba, or the Tallapoosa Drainages. Archaeological records from these drainages are doubtful since tulotoma snails were Indian food items with shells of ornamental value and were likely to be transported outside of their natural range. Collections from these drain-ages since the mid-nineteenth century have not verified the presence of this species.

The snail's current known range includes four localized populations in the lower, unimpounded portions of Coosa River tributaries: Kelly Creek, St. Clair and Shelby Counties; Weogufka and Hatchet Creeks, Coosa County; and Ohatchee Creek, Calhoun County. A single population continues to survive in the Coosa River between Jordan Dam and Wetumpka, Elmore County. All of these locations, with the exception of Ohatchee Creek where only a few snails have been observed, appear to have self-sustaining populations. The tulotoma snail has apparently been extirpated in the Alabama River.

Threats

The range reduction of tulotoma can be attributed to extensive channel modifications in the Coosa-Alabama River System for navigation and hydropower. Dredging of the Alabama River channel began in 1878 and continues to the present day. Locks and dams on that river were completed in the 1960s impounding tulotoma habitat from the lowermost known site near Claiborne, Alabama, to the confluence of the Coosa and Tallapoosa Rivers. The Coosa River has been impounded for hydropower from just above its confluence with the Tallapoosa for approximately 230 river mi (370 river km) by a series of six large dams constructed between 1914 and 1966. Most Alabama and Coosa River tributaries within the historic tulotoma range have been affected in their lower reaches by backwater from the impoundments.

Additional impacts on the species include pollution, siltation, and hydropower discharge. Industrial and municipal waste problems were found in the Coosa Drainage as well as the effects of excessive siltation. In a 1989 survey, Service biologists noted that tulotoma habitat in the river channel and tributaries affected by reservoir backwater may be limited by siltation.

Conservation and Recovery

The Alabama Power Company is conducting a multi-year life history and population study on the tulotoma snail in the Coosa River below Jordan Dam, Elmore County, Alabama. Information from this study should be used to access historic sites where the species no longer occurs. The suitability of the habitat would be evaluated for reintroduction of the snail. Known populations will be monitored and protected through existing legislation and regulations.

Contacts

U.S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30334
http://southeast.fws.gov/

U.S. Fish and Wildlife Service
6578 Dogwood View Parkway
Jackson, Mississippi 39213
Telephone: (601) 965-4900

References

Hershler, R., J.M. Pierson, and R.S. Krotzer. 1990."Rediscovery of Tulotoma magnifica (Conrad) (Gastropoda: Viviparidae)." Proceedings of the Biological Society of Washington. 103 (4): 815-824.

U.S. Fish and Wildlife Service. 9 January 1991. "De-termination of Endangered Status for the Tulotoma Snail." Federal Register 56 (6): 797-800.