Threeridge - Amblema plicata
Federal Status: Not listed (Watters 1995)
Ohio Status: Not listed (Watters 1995)
Key characteristics: Elongate or rounded shell with ridges or folds on the posterior half (Cummings, Mayer 1992).
Similar species: Washboard, rock-pocketbook (Cummings, Mayer 1992).
Description: Shell thick, elongate or rounded, and compressed to inflated. Anterior end rounded, posterior end rounded or bluntly pointed. Dorsal margin straight, ventral margin straight to curved. Umbos low, equal to or slightly elevated above the hinge line. Beak sculpture of three or four ridges usually seen only in young shells. Shell smooth on the anterior third, with three or more roughly parallel ridges or folds on the posterior two-thirds. Shells from large rivers generally more inflated and without as many folds or wrinkles as those found in smaller streams. Periostracum yellowish green, light brown, or green in juveniles, becoming dark green, brown, or black in older shells. Length to 7 inches (17.8 cm) (Cummings, Mayer 1992).
Pseudocardinal teeth serrated and well developed; two in the left valve, one in the right (occasionally with a small tooth on either side). Lateral teeth serrated and straight to slightly curved; two in the left valve, one in the right. Beak cavity medium to deep. Nacre pearly white, frequently stained, iridescent posteriorly. Some individuals with a purple tint on the posterior end (Cummings, Mayer 1992).
Hosts: Black and white crappie, bluegill, green sunfish, pumpkinseed, flathead catfish, largemouth, white, and rock bass, northern pike, sauger, shortnose gar, yellow perch (Watters 1995).
Habitat: Rivers and impoundments in sand, mud, or gravel (Cummings, Mayer 1992).
Return to the Introduction of Freshwater Mussels
Return to the Biology Home Page
Return to the Marietta College Home Page