Shell thick, oval or oblong, somewhat elongate, and slightly inflated. Anterior end rounded; posterior end bluntly pointed. Dorsal margin straight, ventral margin curved anteriorly, straight posteriorly. Umbos slightly elevated above hinge line. Beak sculpture of two heavy ridges, visible only in young shells. Shell smooth, except for a row of knobs or tubercles on center of valve, running from umbo to ventral margin. A shallow sulcus (furrow) is present between row of tubercles and posterior ridge. Epidermis yellow or light brown in juveniles, becoming chestnut to dark brown in adults.
Pseudocardinal teeth small relative to overall shell size; two in left valve, one in right (with occasional smaller tubercular tooth on either side). Lateral teeth long, straight or slightly curved; two in left valve, one in right. Beak cavity shallow. Nacre white, occasionally tinged with pink or salmon.
Similar species: White wartyback, threehorn wartyback, round pigtoe, Wabash pigtoe.