Federal
Status: Not listed (Watters 1995)
Sheep nose - Plethobasus cyphyus
Federal
Status: Not listed (Watters 1995)
Ohio Status: Endangered (Watters 1995)
Key characteristics: Oblong shell with a smooth surface except for a single row of bumps or knobs running from the umbo to the ventral margin (Cummings, Mayer 1992).
Similar species: White wartyback, threehorn wartyback, round pigtoe, Wabash pigtoe, hickorynut (Cummings, Mayer 1992).
Description: 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 the hinge line. Beak sculpture of two heavy ridges, visible only in young shells. Shell smooth, except for a row of knobs or tubercles on the center of the valve, running from the umbo to the ventral margin (some- times obscure). A shallow sulcus or furrow present between the row of tubercles and the posterior ridge. Periostracum yellow or light brown in juveniles, becoming chestnut to dark brown in adults. Length to 5 inches (12.7 cm) (Cummings, Mayer 1992).
Pseudocardinal teeth rather small relative to overall shell size; two in the left valve, one in the right (occasionally with a smaller tubercular tooth on either side). Lateral teeth long, straight or slightly curved; two in the left valve, one in the right. Beak cavity shallow. Nacre white, occasionally tinged with pink or salmon (Cummings, Mayer 1992).
Hosts: Sauger (Watters 1995)
Habitat: Medium to large rivers in gravel or mixed sand and gravel (Cummings, Mayer 1992).
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