Field Guide

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.

Pulmonate, or lunged snails breathe via a lunglike pulmonary cavity, and they lack the hard trapdoor-like operculum found in gilled snails. Except for in the Ozarks, pulmonate snails predominate in most of the aquatic regions in our state.

Ramshorn snails are easy to identify at a glance, because the shell is a flat, disklike coil. Like other pulmonate aquatic snails, they lack the hard horny “trapdoor” possessed by other types of aquatic snails.

The Chinese mysterysnail is a nonnative invasive species quickly taking over urban waters throughout the state. Never release aquarium species or aquarium water into natural aquatic habitats. Learn about and practice clean boating techniques so that you do not accidentally spread invasive aquatic species.

The Neosho midget crayfish is a subdued mottled brown, with a prominent black band crossing the carapace near its junction with the abdomen. The pincers are broad and powerful. This small, stout crayfish is found in the Neosho stream drainage of southwestern Missouri and northwestern Arkansas.

Of Missouri’s two species of freshwater shrimp, the Mississippi grass shrimp is by far the most common and widespread.