Hemistena lata (Rafinesque, 1820)
Other common names: None.
Key characters: Thin, elongate shell, yellowish brown with broken green rays, poorly developed teeth, purple or pinkish nacre near the beak cavity.
Description: Shell thin, elongate, and compressed. Anterior end rounded, posterior end pointed. Dorsal margin straight, ventral margin straight to slightly curved. Umbos low, not elevated above the hinge line. Beak sculpture of three or four weak ridges. Periostracum yellowish brown or tan with broken green rays on some shells. Length to 4 inches (10.2 cm).
Teeth poorly developed. Pseudocardinal teeth as a thickened knob or ridge, one in each valve. Lateral teeth as a thickening of the hinge line. Beak cavity very shallow or absent. Nacre bluish white, with light purple or pink in the beak cavity area.
Habitat: Medium to large rivers in mud, sand, or gravel.
Status: Federally Endangered. Likely extirpated from the Midwest.