Cylindrical Lioplax

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Cylindrical Lioplax

Lioplax cyclostomaformis

ListedOctober 28, 1998
DescriptionA gill-breathing, freshwater snail.
HabitatLives in mud among rocks in fast-flowing streams and rivers.
FoodFilter-feeds on organic detritus.
ReproductionThought to brood its young in its gills.
ThreatsHabitat destruction and degradation.


The Lioplax cyclostomaformis (cylindrical lioplax), is a gill-breathing snail in the family Viviparidae. The shell is elongate, reaching about 1.1 in (2.8 cm) in length. Shell color is light to dark olivaceous-green externally, and bluish inside of the aperture (shell opening). The cylindrical lioplax is distinguished from other viviparid (eggs hatch internally and the young are born as juveniles) snails in the Mobil River Basin by the number of whorls, and differences in size, sculpture, microsculpture, and spire angle.


The cylindrical lioplax is thought to brood its young and to filter-feed on organic detritus, as do better-known members of the Viviparidae. Life spans have been reported to be 3-11 years in other species of Viviparidae.


Habitat for the cylindrical lioplax is unusual for the genus, as well as for other genera of viviparid snails. It lives in mud under large rocks in rapid currents over stream and river shoals. Other lioplax species are usually found in exposed situations or in mud or muddy sand along the margins of rivers.


The cylindrical lioplax is currently known only from approximately 15 mi (24 km) of the Cahaba River above the Fall Line in Shelby and Bibb counties, Alabama. Survey efforts in 1974 failed to locate this snail in the Coosa or Alabama Rivers, and more recent survey efforts have also failed to relocate the species at historic localities in the Alabama, Black Warrior, Little Cahaba, and Coosa Rivers and their tributaries.


More than 90% of the historical habitat of the cylindrical lioplax has been destroyed by the extensive construction of numerous dams and inundation by impounded waters. Habitat downstream of impoundments has also been degraded by changes in hydrology, water quality, and eutrophication. Discharges associated with agriculture and municipal sources are also important in some areas. These are ongoing threats to the rare snail.

Conservation and Recovery

The cylindrical lioplax is currently known only from about 15 mi (24 km) of the Cahaba River. Its habitat is all on privately owned land. The remaining critical habitat of the cylindrical lioplax should be protected. This could be done by acquiring the private land and establishing ecological reserves, or by negotiating conservation easements with the landowners. The populations of the cylindrical lioplax should be monitored, and research undertaken into its biology and habitat needs, including methods of beneficial management. Additional populations of the rare snail should be established in areas with suitable habitat.


U. S. Fish and Wildlife Service
Wildlife and Habitat Management Office
6578 Dogwood View Parkway
Jackson, Mississippi 39213
Telephone: (601) 965-4903

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345


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