Eastern Fan Shell - Cyprogenia stegaria
Federal Status: Endangered (Watters 1995)
Ohio Status: Endangered (Watters 1995)
Key characteristics: Rounded shape, numerous pustules, elevated growth lines, broken green rays (Cummings, Mayer 1992).
Similar species: Pimpleback, purple pimpleback (Cummings, Mayer 1992).
Description: Shell rounded, solid, and moderately inflated. Anterior margin rounded, posterior margin bluntly rounded or truncated. Ventral margin broadly rounded. Umbos not elevated above the hinge line. Beak sculpture, if visible, of a few weak ridges. Growth lines appear as distinct elevated ridges. Numerous pustules usually concentrated in the center but occasionally covering the entire surface of the shell. Periostracum usually greenish yellow, with a pattern of dark green rays made up of numerous smaller broken lines or dots. Length to 3 inches (7.6 cm) (Cummings, Mayer 1992).
Pseudocardinal teeth relatively large and serrated; two in the left valve, one in the right. Lateral teeth roughened, straight to slightly curved, heavy and very short. Interdentum wide. Beak cavity shallow to moderately deep. Nacre white, iridescent posteriorly (Cummings, Mayer 1992).
Hosts: Unknown (Watters 1995)
Habitat: Medium to large rivers in gravel riffles (Cummings, Mayer 1992).
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