Field Guide

The shell of this mollusk is large and impressive in overall size. Although fairly flat, it can be more than 8 inches long. A large wing on the heelsplitter can be painful if you step on it.

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.

Like the pink heelsplitter and fragile and pink papershells, the bluefer uses freshwater drum as a host.

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.

The Mammoth Spring crayfish has a very localized distribution: In our state, it lives only in the Warm Fork of Spring River, in Oregon County. It is reddish brown, and its broad, powerful pincers have numerous blackish specks on their basal parts.

Today found only in the Meramec River, the elephantear has been classified as endangered in Missouri and is a candidate for federal endangered status.

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

Zebra mussels are named for their shells, which have alternating light and dark bands. They are a highly invasive nonnative species. Learn how to prevent their spread.

Gilled snails are one of two main groups of aquatic snails in Missouri (the other group is the "lunged" snails). Gilled snails, or prosobranchs, breathe with gills and possess a hard trapdoor-like operculum. They are most common in the Ozarks.