Round Rocksnail

Leptoxis ampla

Description

The Leptoxis ampla (round rocksnail) grows to about 0.8 in (2 cm) in length. The shell is spherical with an ovately rounded aperture. The body whorl is shouldered at the suture, and may be ornamented with folds or plicae. Color may be yellow, dark brown, or olive green, usually with four entire or broken bands. There are slight differences in DNA sequencing between the painted rocksnail and the round rocksnail, and they are considered to be sister species although they could represent isolated populations belonging to a single species.

Behavior

The round rocksnail is known to graze on algae found on rocks. In addition, the round rocksnail lays its eggs on rocks in order to reproduce.

Habitat

Round rocksnails inhabit riffles and shoals over gravel, cobble, or other rocky substrates. The round rocksnail is the only surviving rocksnail species in the Cahaba River drainage.

Distribution

The round rocksnail was historically found in the Cahaba River, and its tributary, Little Cahaba River, Bibb County, Alabama; and the Coosa River, El-more County, and tributaries—Canoe Creek and Kelly's Creek, St. Clair County; Ohatchee Creek, Calhoun County; Yellowleaf Creek, Shelby County; and Waxahatchee Creek, Shelby/Chilton Counties, Alabama.

The round rocksnail is currently known from a shoal series in the Cahaba River, Bibb and Shelby Counties, Alabama, and from the lower reach of the Little Cahaba River, and the lower reaches of Shade and Six-mile creeks in Bibb County, Alabama.

Threats

The round rocksnail has lost more than 90% of its historical range because of habitat destruction caused by impoundment, and pollution by siltation and chemicals associated with coal mining and land-use practices. It only survives in a shoal series in the Cahaba River (in Bibb and Shelby Counties, Alabama), from the lower reach of the Little Cahaba River, and the lower reaches of Shade and Six-mile Creeks (both in Bibb County). Its few surviving populations are small, isolated, and vulnerable to impoundment, degradation of water quality, other disturbances, and random catastrophic events.

Conservation and Recovery

The round rocksnail only survives in a few, small, isolated, critical habitats. It is crucial that its few habitats are protected from any proposed impoundment, and from pollution associated with coal mining, agricultural land-use, or other sources. The surviving populations of the round rocksnail should be monitored, and research undertaken into its biology and ecological needs, including work on its propagation. If suitable habitat can be found, additional populations should be established.

Contacts

U. S. Fish and Wildlife Service
Jackson Ecological Services Field Office
6578 Dogwood View Parkway, Suite A
Jackson, Mississippi 39213-7856
Telephone: (601) 965-4900

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
http://southeast.fws.gov/

Reference

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.