Scientific Name: Strophitus undulatus

Classification:  State Threatened

Photo Credit: NCWRC




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

Shells of the creeper tend to be rather thin and fragile. Specimens may reach over 100 mm in length in North Carolina. The periostracum is generally smooth and shiny. The color may range from yellowish to dark brown. Green rays may extend over the entire surface of the shell. The anterior end is rounded and the posterior end is rounded except a straight margin may exist near the terminus of the posterior ridge. The dorsal margin is straight with the umbos extending above this margin. The ventral margin is irregularly rounded. Growth rests are clearly evident when the shell is held toward a bright light. The posterior slope tends to be roughened even on shells tending to be smooth. Lateral teeth are absent and the pseudocardinal teeth are vestigial in each valve. The nacre tends to be iridescent and ranges in color from gray to blue. The nacre may be extensively colored salmon.


Shell Anatomy

The range of the creeper includes both the Atlantic Slope and the Interior Basin. It is found through the Mississippi and Ohio drainages from Central Texas to Lake Winnipeg, Canada. In the Atlantic Slope it occurs from the Savannah River in South Carolina to the St. Lawrence River in Canada (Johnson 1970).

Distribution by County: French Broad River Basin: Transylvania Co. (Little River Subbasin, French Broad River), Henderson Co. (Cane Creek Subbasin, French Broad River), BuncombeCo. (French Broad River). Broad River Basin: Polk Co. (Green River). Pee Dee River Basin: Union Co. (Goose Cr. Subbasin), Stanly Co. (Bear Cr. Subbasin), Montgomery Co. (Barnes and Densons creek subbasins, Little River Subbasin), Randolph Co. (Caraway Cr. Subbasin). Cape Fear River Basin: Moore Co. (Deep River Subbasin), Chatham Co. (Rocky River Subbasin, Buckhorn Cr. Subbasin), Alamance Co. (Stinking Quarter Cr. Subbasin), Orange Co. (Cane Cr. Subbasin). Neuse River Basin: Orange Co. (Eno and Little river subbasins), Person Co. (Flat River Subbasin), Durham Co. (Flat and Little river subbasins), Wake Co. (Crabtree, Swift, and Middle creek subbasins), Johnston Co. (Middle and Swift creek subbasins, Little River Subbasin), Nash Co. (Moccasin and Turkey creek subbasins), Wilson Co. (Moccasin, Turkey, and Contentnea creek subbasins), Jones Co. (Trent River Subbasin). Tar River Basin: Person Co. (Tar River Subbasin), Granville Co. (Shelton and Cub creek subbasins, and Tar River Subbasin), Vance Co. (Ruin and Tabbs creek subbasins), Franklin Co. (Sandy, Fox, and Crooked creek subbasins), Nash Co. (Stony and Swift creek subbasins, Tar River Subbasin), Warren Co. (Fishing and L. Fishing creek subbasins), Halifax Co. (L. Fishing Cr. Subbasin). Roanoke River Basin: Person Co. (Mayo Cr.

Subbasin), Caswell Co. (Country Line Creek Subbasin), Granville Co. (Aarons Cr. Subbasin). NOTE: All headwater areas that flow into these occupied habitats should receive special management.


This species has been taken from silt, sand, gravel, and mixed substrates. Throughout its range it has been found from headwater streams to large rivers and lakes to a depth of 4 meters (Gordon and Layzer 1989).
This species is a long term brooder with gravid females being found throughout the year (Gordon and Layzer 1989). Hermaphroditic creepers have occasionally been found (van der Schalie 1970). Ellis and Keim (1918) identified the green sunfish (Lepomis cyanellus) as one fish host, and Baker (1928) identified the creek chub (Semotilus atromaculatus) and the largemouth bass (Micropterus salmoides) as other fish hosts.


General Life History For Mussels