Illinois Natural History Survey - University of Illinois

Lampsilis fasciola Rafinesque, 1820

Wavy-rayed lampmussel


Lampsilis fasciola, INHS 8616Lampsilis fasciola, INHS 8616. Salt Fork Vermilion River, Vermilion County, Illinois.
Length: 3.0 inches (7.6 cm) for male (top), 2.8 inches (7.1 cm) for female (bottom).Lampsilis fasciola distribution

Other common names Wavy-lined lampmussel.

Key characters A rounded shell, moderately thick in adults, yellow or yellowish green, with numerous thin wavy green rays.

Similar species Plain pocketbookpocketbook.

Description Shell moderately thick, round or ovate, compressed to inflated. Anterior end rounded, posterior end bluntly pointed in males, truncated in females. Dorsal margin straight, ventral margin curved. Umbos only slightly elevated above the hinge line. Beak sculpture of three to five indistinct wavy ridges. Shell smooth, yellow or yellowish green, with numerous thin, wavy green rays. Length to 3.5 inches (8.9 cm).

Pseudocardinal teeth triangular, short, thick, and divergent; two in the left valve, one in the right, occasionally with a smaller tooth on either side. Lateral teeth short and straight or slightly curved. Beak cavity moderately deep. Nacre white, iridescent posteriorly.

Habitat Medium-sized streams in gravel riffles.

Status Widely distributed but uncommon in northern tributaries of the Ohio River. Endangered in Illinois. Species of Special Concern in Indiana and Michigan. Species of Special Interest in Ohio.

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