Lampsilis higginsii (Lea, 1857)
Lampsilis higginsii, INHS 4602 and 11767. Mississippi River, Rock Island County, Illinois.
Other common names None.
Key charactersRounded to slightly elongate, thick, smooth, and inflated shell, yellowish brown, with green rays; posterior end bluntly pointed in males, truncated in females.
Description Shell rounded to slightly elongate, solid, and inflated. Anterior end rounded, posterior end bluntly pointed (males) or truncated (females). Dorsal margin straight, ventral margin straight to slightly curved. Umbos turned forward and elevated above the hinge line. Beak sculpture, if visible, of three or four double-looped ridges. Shell smooth, yellow, yellowish green, or brown with green rays, obscure on some individuals. Length to 4 inches (10.2 cm).
Pseudocardinal teeth triangular, thick, divergent; two in the left valve, one in the right, occasionally with a smaller tubercular tooth in front. Lateral teeth fairly long, moderately heavy, and straight. Beak cavity deep. Nacre white, often tinged with cream or salmon near the beak cavity, iridescent posteriorly.
Habitat Mississippi River and some of its larger northern tributaries in gravel or sand.
Status Federally Endangered.