North Carolina Wildlife Resources Commission

Tennessee Pigtoe

Scientific Name: Fusconaia barnesiana

Classification:  State Endangered

Photo Credit: NCWRC
   

Interior

 

Exterior 

NOTE: Hover over the bold words for definitions or see the Glossary.

The periostracum is brownish-yellow, tending to become darker with age. Narrow green rays may be present around the umbo and along the posterior ridge for most of its length. Both the anterior and posterior ends are rounded, and the ventral margin is regularly rounded. The posterior ridge tends to be angular. Growth rests are distinct and the periostracum is roughened over most of its surface. The right valve has two pseudocardinal teeth, the more anterior tooth tending to be vestigial. An interdental projection may be present or tends to be vestigial. There is one lateral tooth in the right valve. Two stumpy pseudocardinal teeth are present in the left valve. The two lateral teeth are distinct and clearly separated by a deep channel running between them. The nacre is white with some signs of iridescence toward the posterior end. The shell is thicker toward the anterior end. Both the anterior and posterior adductor muscle scars are well impressed. Also, the pallial line is distinct and well impressed.

 

Shell Anatomy

 

The Tennessee pigtoe is a Tennessee River Basin endemic species. Extant populations exist in the Clinch, Little, Nolichucky, Powell, Little Tennessee, Elk, Duck, and Buffalo rivers (Starnes and Bogan 1988). In North Carolina, this species is only found in a short stretch of the Little Tennessee River above Fontana Reservoir and in the Hiwassee River, Cherokee County.

Distribution by County: Tennessee River Basin: Cherokee Co. (Hiwassee River); Swain Co. (Little Tennessee River). NOTE: All headwater areas that flow into these occupied habitats should receive special management.

 


This species prefers riffles and shoals. Throughout most of its range it is found in clean-swept substrates of sand, gravel, and mixed habitats of sand, gravel, and cobble. It is rare in pools and slack waters (S. Ahlstedt 1984).

The Tennessee pigtoe is a short-term breeder (tachytictic) (Ortmann 1919). Additional information is not available for this species.

 

General Life History For Mussels

Reservoirs isolate the small populations of the Tennessee pigtoe in North Carolina from other local populations of the species in Tennessee; therefore, if populations are lost in our state, natural reestablishment would be impossible.