Pimpleback - Quadrula pustulosa


Federal Status: Not listed (Watters 1995)

Ohio Status: Not listed (Watters 1995)

Key characteristics: Rounded shell, a green stripe on the umbo, usually densely covered with pustules. Beak cavity deep and open, not compressed as in the purple wartyback (Cummings, Mayer 1992).

Similar species: Orange-foot pimpleback, purple wartyback, wartyback, mapleleaf (Cummings, Mayer 1992).

Description: Shell thick, rounded, and compressed to moderately inflated. Anterior end rounded, posterior end rounded to somewhat truncated. Dorsal margin straight, ventral margin curved. Umbos elevated above the hinge line. Beak sculpture, when present, of two or three very small ridges. Shell normally smooth on the anterior half; posterior half or two-thirds covered with pustules or bumps (rarely absent). Periostracum yellowish-green to light brown in small shells, becoming chestnut to dark brown in older shells. A broad, broken green ray present on the umbo extending toward the ventral margin, may be indistinct on older shells. Length to 4 inches (10.2 cm) (Cummings, Mayer 1992).

Pseudocardinal teeth serrated and well developed; two in the right valve, one in the left (occasionally with a small tooth on either side). Lateral teeth heavy, serrated, and straight to slightly curved; two in the left valve, one in the right. Beak cavity deep. Nacre pearly white, iridescent posteriorly (Cummings, Mayer 1992).

Hosts: Blask and brown bullhead, channel and flathead catfish, white crappie(Watters 1995).

Habitat: Medium to large rivers in mud, sand, or gravel (Cummings, Mayer 1992).


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