North Carolina Wildlife Resources Commission

Roanoke Slabshell (I. Lea, 1838)

Scientific Name: Elliptio roanokensis

Classification:  State Threatened

Photo Credit: NCWRC




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

Roanoke slabshells grow to greater than 150 mm total length. In North Carolina, it is one of our largest freshwater mussels species. The posterior ridge varies from being well defined to being uniformly rounded. The periostracum is generally smooth except near the margins of the shell. Growth rests are distinct. The color of the periostracum is usually a yellow-reddish-brown that darkens with age. Narrow greenish rays are often present from the anterior end of the shell to the posterior ridge. The rays are less distinct in larger individuals. The nacre is usually iridescent. Three distinctive characteristics of this species are the presence of small folds (plications) centrally located on the periostracum of most individuals, certain of the incurrent papillae being subdivided into smaller papillae, and irregularly developed branchial septa.


Shell Anatomy

The Roanoke slabshell ranges from at least the Roanoke River in North Carolina to the Savannah River in Georgia and South Carolina. Walter (1954) considered the range from the Connecticut River to the Altamaha River.

Distribution by County: Pee Dee River Basin: Montgomery County (Uwharrie River Subbasin), Richmond County (Pee Dee River). Cape Fear River Basin: Cumberland Co. (Cape Fear River); Harnett Co. (Cape Fear River). Neuse River Basin: Wake Co. (Middle Cr.), Johnston Co. (Neuse River, Mill Cr. Subbasin, and Swift Cr. Subbasin). Tar River Basin: Nash Co. (Tar River, Swift and Fishing creek subbasins), Edgecombe Co. (Tar R., Swift and Fishing creek subbasins), Halifax Co. (Fishing Cr. Subbasin). Roanoke River Basin: Halifax Co. (Roanoke River); Northampton Co. (Roanoke River). NOTE: All headwater areas that flow into these occupied habitats should receive special management.


In the Tar River, the Roanoke slabshell is usually found associated with the deeper channels near shore in relatively fast flowing water. The substrate consists of coarse to medium sized sands and small gravel. The species is also associated with coarser substrates, such as a mix of gravel and cobble seen in the Cape Fear River in Harnett County.

Little is known of the life history of this species. However, gravid females are found as early as March. In general, the best populations exist in rivers and creeks downstream from the last major dams within the river basins. This suggests that dominant fish hosts are anadromous.


General Life History For Mussels