Flat Pebblesnail

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Flat Pebblesnail

Lepyrium showalteri

ListedOctober 28, 1998
DescriptionA small freshwater snail.
HabitatOccurs in rapid currents of rocky river shoals.
FoodProbably feeds on algae growing on rocks.
ReproductionLays capsule of eggs on rocks.
ThreatsHabitat destruction and degradation.


The flat pebblesnail, Lepyrium showalteri, is a small snail in the family Hydrobiidae; however, the species has a large and distinct shell, relative to other hydrobiid species. This snail's shell is also distinguished by its depressed spire and expanded, flattened body whorl. The shells are ovate in outline, flattened, and grow to 0.1-0.2 in (2.5-5 mm) high and 0.2 in (5 mm) wide. The umbilical area is imperforate (no opening), and there are tow to three whorls which rapidly expand.


Eggs are laid singly in capsules on hard surfaces. Little else is known of the natural history of this species. It probably feeds on algae growing on rocks.


The flat pebblesnail is found attached to clean, smooth stones in rapid currents of river shoals.


The flat pebblesnail was historically known from the mainstem Coosa River in Shelby and Talladega Counties, the Cahaba River in Bibb and Dallas Counties, and Little Cahaba River in Bibb County, Alabama.


The flat pebblesnail has suffered the loss of more than 90% of its original habitat through the construction of dams and impoundments, and to a lesser degree the degradation of water quality by sedimentation and pollution by nutrients. It not been found in the Coosa River portion of its range since the construction of Lay and Logan Martin Dams, and recent survey efforts have failed to locate any surviving populations outside of the Cahaba River drainage. The flat pebblesnail is currently known from one site on the Little Cahaba River, Bibb County, and from a single shoal series on the Cahaba River above the Fall Line, Shelby County, Alabama.

Conservation and Recovery

The only surviving critical habitats of the flat pebblesnail are on privately owned land. It is crucial that these habitats are protected from destruction by the construction of new dams or impoundments. Land-use in the watersheds of the habitats must be modified to reduce erosion and sedimentation, nutrient inputs, and other potentially degrading influences. This can be done by instituting best-management practices in local forestry, agriculture, and construction activities. The populations of the flat pebblesnail should be monitored, and research undertaken into its biology and habitat needs.


U.S. Fish and Wildlife Service
Jackson Ecological Services Field Office
6578 Dogwood View Parkway, Suite A
Jackson, Mississippi 39213
Telephone: (601) 965-4900
Fax: (601) 965-4340


U.S. Fish and Wildlife Service. 28 October 1998. "Endangered and Threatened Wildlife and Plants; Endangered Status for Three Aquatic Snails, and Threatened Status for Three Aquatic Snails in the Mobile River Basin of Alabama." Federal Register 63 (208): 57610-57620.