Round Pigtoe - Pleurobema coccineum
Federal Status: Not listed (Watters 1995)
Ohio Status: Special interest (Watters 1995)
Key characteristics: A highly variable shell that is relatively large, rounded or elongate, chestnut or brown, with a shallow beak cavity (Cummings, Mayer 1992).
Similar species: All other pigtoes (Fusconaia and Pleurobema), hickorynut, round hickorynut (Cummings, Mayer 1992).
Description: Shell moderately thick, round, and compressed (medium-sized rivers) to inflated (large rivers). Anterior end rounded, posterior end rounded to bluntly pointed. Dorsal margin straight to slightly curved, ventral margin usually curved. Umbos low and only slightly elevated above the hinge line. Beak sculpture of two or three elevated ridges on the umbo. Shell smooth. Periostracum greenish brown, light brown, or reddish brown in juveniles, becoming chestnut or dark brown in adults, with faint green rays visible near the beaks in some shells. Length to 4 inches (10.2 cm) (Cummings, Mayer 1992).
Pseudocardinal teeth well developed; two in the left valve, one in the right. Lateral teeth straight. Beak cavity shallow (medium-sized rivers) to moderately deep (large rivers). Nacre variable from white to pink or rose-colored (Cummings, Mayer 1992).
Hosts: Bluegill (Watters 1995).
Habitat: Medium to large rivers in mud, sand, or gravel (Cummings, Mayer 1992).
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