Field Guide

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.

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

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 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.

Williams' crayfish is small and rather plain, without bright colors or bold markings. It has a pale, vase-shaped zone along the middle of the dark olive-tan carapace. It is found only in the upper White River drainage of Missouri and Arkansas.

The pincers of Meek's crayfish are sprinkled with many blackish spots. There is a dark spot near the tubercle at the base of the moveable finger. In Missouri, this rare crayfish occurs in only a few tributaries of Table Rock Lake in Stone County.