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Shiny Pigtoe Pearlymussel

Shiny Pigtoe Pearlymussel

Fusconaia cor

Status Endangered
Listed June 14, 1976
Family Unionidae (Freshwater Mussel)
Description Smooth, shiny, dull brown shell with dark green or black rays.
Habitat Shoals in streams and rivers.
Reproduction Breeds in spring and releases glochidia by mid-to late summer of the same year.
Food Parasitic on the gills of fish.
Threats Loss of habitat, siltation, pollution
Range Alabama, Tennessee, Virginia


The shiny pigtoe pearlymusselFusconaia cor orF. edgariana is about 2.5 in (6.4 cm) long with a very smooth and shiny outer covering (periostracum). The shell displays prominent dark green to black rays on a yellow to brown background. Young specimens generally have bold black or green ray patterns; older mussels are dull brown with indistinct rays fading toward the valve margins. Valves are triangular with concentric growth marks. The inner shell surface is white.


The shiny pigtoe is a short-term breeder, breeding in spring and releasing glochidia (larvae) by mid-to late summer of the same year. The glochidia of the shiny pigtoe are horseshoe shaped and parasitic on the gills of fish. Some of the fish hosts are the whitetail shiner, common shiner, the warpaint shiner, and the telescope shiner.

For more on the reproduction and diet of freshwater mussels, see the Upland Combshell (Epioblasma metastriata ) entry.


The shiny pigtoe is found along fords and in shoals of clear, moderate-to fast-flowing streams and rivers with stable substrates. It is not found in deeper pools or reservoirs.


The shiny pigtoe was once found in Alabama in the Elk, Flint, and Paint Rock Rivers, and in the Clinch River from Russell County, Virginia, downstream to Anderson County, Tennessee. It was found in the Powell River from Lytton Mill in Lee County, Virginia, downstream to Claiborne County, Tennessee. It was also found in the Holston River in Washington County, Virginia, downstream to Hawkins County, Tennessee, and in the Tennessee River from Knoxville downstream for 20 mi (32 km).

The shiny pigtoe is now found in the North Fork Holston River in Virginia from Broadford to Saltville. In the Clinch River, it is found in scattered locations from Nash Ford in Virginia to Kyles Ford, Tennessee, with smaller populations in the Copper Creek tributary. In the Powell River it occurs sporadically from Flanary's Ford, Virginia, downstream to Combs, Tennessee. In the Elk River it inhabits scattered localities near Fayetteville, Tennessee. A few populations occur in the Paint Rock River near Princeton, Alabama. As of 2000, no recent population figures were available.


Like other freshwater mussels the shiny pigtoe has suffered from the industrialization of its range and the massive Tennessee Valley Authority projects that have dammed and redirected all of the major rivers and streams within its historic range. In addition, runoff from strip mining, coal washing, herbicides, pesticides, and industrial pollutantsparticularly heavy metalshas severely degraded water quality throughout the mussel's range.

Conservation and Recovery

It is unlikely that any major portion of the shiny pigtoe's historic habitat will ever be restored. Therefore, recovery strategies are focused on preserving habitat in the areas where the mussel can still be found. Some portions of the range, including the Paint Rock River, may be eligible for "scenic river" status under the National Wild and Scenic Rivers Act, a designation that would provide additional protection for the species.


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
Regional Office, Division of Endangered Species
300 Westgate Center Dr.
Hadley, Massachusetts 01035-9589
Telephone: (413) 253-8200
Fax: (413) 253-8308


Bogan, A. E., and P. W. Parmalee. 1983. Tennessee's Rare Wildlife: The Mollusks. Tennessee Wildlife Resources Agency, University of Tennessee Press, Knoxville.

Burch, J. B. 1975. Freshwater Unionacean Clams (Mollusca: Pelecypoda) of North America. Malacological Publications, Hamburg, Mich.

U. S. Fish and Wildlife Service. 1983. "Recovery Plan: Shiny Pigtoe Pearly Mussel, Fusconaia edgar-iana. " U. S. Fish and Wildlife Service, Atlanta.

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