Field Guide

The plain pocketbook is one of the most common and widespread mussels in our state. It is oval, relatively large, and occurs frequently.

Round pigtoes are more rounded than Wabash pigtoes. Usually, the nacre (the shell lining) is white, but in rare individuals it is bright pink.

Among all the mussels of Missouri, this is perhaps the easiest to recognize: As the shell grows, large knobs are produced, first on one shell and then on the other, in an alternating pattern.

Sometimes called the blue-point, this mussel species is widely distributed in Missouri rivers and is occasionally found along reservoir margins.

This favored habitat of this vulnerable species is large streams or rivers in firm sand and mud. The bumps on the shell may help to anchor it in the river bottom.

The uniform shell thickness and hard, white nacre made this mussel a favorite for button manufacturing, in the days before most buttons were made of plastic.

The longpincered crayfish is large and colorful, with very long, slender, blue-green pincers that are studded with prominent yellowish knobs. It is restricted to the White River basin in the Ozarks.

This endangered native mussel lives in flowing waters of large streams among gravel and cobble.

Of Missouri’s two species of freshwater shrimp, the Ohio River shrimp is certainly the rarest. It was thought to be extirpated from our state but was rediscovered recently in the Mississippi River.