|Listed||October 28, 1998|
|Description||A small, dark brown to black, aquatic snail.|
|Habitat||Rocky shoals and gravel bars in flowing reaches of larger rivers.|
|Food||Algae (periphyton) grazed from rocks.|
|Threats||Habitat destruction by impoundments and degradation by pollution.|
The Elimia crenatella, (lacy elimia) is a small species in the family Pleuroceridae. Growing to about 0.4 in (1 cm) in length, the shell is conic in shape, strongly striate, and often folded in the upper whorls. Shell color is dark brown to black, often purple in the aperture, and without banding. The aperture is small and ovate. The lacy elimia is easily distinguished from other elimia species by a combination of size, ornamentation, and color.
Most elimia species graze on periphyton growing on bottom substrates. Individual snails are either male or female. Eggs are laid in early spring and hatch in about two weeks. Snails apparently become sexually mature in their first year, but in some species females may not lay until their second year. Some elimia may live as long as five years.
The lacy elimia is usually found in tight clusters or colonies on larger rocks within a shoal. Elimia snails are gill breathing snails that typically inhabit highly oxygenated waters on rock shoals and gravel bars.
The lacy elimia was historically abundant in the Coosa River main stem from St. Clair to Chilton County, Alabama, and was also known in several Coosa River tributaries—Big Will's Creek, DeKalb County; Kelley's Creek, St. Clair County; and Choccolocco and Tallaseehatchee Creeks, Talladega County, Alabama. The lacy elimia has not been recently located at any historic collection site. However, as a result of the recent survey efforts, previously unreported populations were discovered in three Coosa River tributaries—Cheaha, Emauhee, and Weewoka Creeks, Talladega County, Alabama. The species is locally abundant in the lower reaches of Cheaha Creek. This stream originates within the Talladega National Forest; however, no specimens of the lacy elimia have been collected on Forest Service lands. The species has also been found at single sites in Emauhee and Weewoka Creeks, where specimens are rare, and difficult to locate.
The lacy elimia has been eliminated from more than 90% of its historical habitat. This has been caused by the destruction of its shoal habitat by the construction of impoundments, and the degradation of water quality by sedimentation and pollution by nutrients. There are now only three known populations of the lacy elimia. It occurs in small stream channels in Cheaha, Emauhee, and Weewoka Creeks.
Conservation and Recovery
The habitats of the lacy elimia are on privately owned land. It is crucial that these critical habitats are protected from destruction by the construction of new dams or impoundments. Land-use in the watersheds of the aquatic 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 lacy elimia should be monitored, and research undertaken into its biology and habitat needs.
U.S. Fish and Wildlife Service
Wildlife and Habitat Management Office
6578 Dogwood View Parkway
Jackson, Mississippi. 39213
Telephone: (601) 965-4900
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.