Field Guide

Aquatic Invertebrates

Showing 1 - 10 of 10 results
Photo of a spothanded crayfish viewed from above on white background.
Crayfishes
About 38 species in Missouri
Crayfish are freshwater aquatic invertebrates that look a lot like small lobsters, to which they are related. There are about 38 species of crayfish in Missouri.
Photo of an aquatic tubificid worm among rocks in an aquarium.
Tubificid Worms (Tubifex Worms)
Tubifex spp. and other aquatic tubificid annelids
Tubificid worms, as a group, include the tubifex worms that aquarists feed to their pet fish. These segmented worms are related to earthworms and like them are detritus eaters.
Water springtails congregate in water above soggy dead leaves
Water Springtail
Podura aquatica
In early spring, clusters of water springtails float on the surface of quiet waters, on muddy banks, and on protruding objects. Adults are bluish gray with reddish appendages.
Photo of a grassland crayfish, also called prairie crayfish.
Grassland Crayfish (Prairie Crayfish)
Procambarus gracilis
The grassland crayfish is rather uniformly colored either bright red or reddish and has broad, powerful pincers. It inhabits prairies and grasslands from Wisconsin and Indiana to Texas, including grasslands in northern and western Missouri.
Photo of a northern, also called virile, crayfish.
Virile Crayfish (Northern Crayfish)
Faxonius virilis (formerly Oronectes virilis)
The virile crayfish is large, reddish brown or green, and lacks prominent markings. The pincers are green with orange tips and are studded with whitish knobs. Paired dark blotches run along the abdomen. This species is widespread.
ellipse
Ellipse and Bleedingtooth
Venustaconcha ellipsiformis and V. pleasii
These small mussels use darters, a type of fish, as hosts for their young.
round pigtoe
Round Pigtoe
Pleurobema sintoxia
Round pigtoes are more rounded than Wabash pigtoes. Usually, the nacre (the shell lining) is white, but in rare individuals it is bright pink.
pond mussel
Freshwater Mussels
Bivalve molluscs in order Unionoida
Secretive and seldom seen, freshwater mussels are extraordinarily diverse in Missouri. We have nearly 70 species within our borders. Many are declining, and several are endangered.
Photo of a ramshorn snail on a wet rock.
Ramshorn Snails
Gyraulus, Helisoma, Menetus, Micromenetus, Planorbula spp.
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.
Photo of a leech
Leeches
Various species in the subclass Hirudinea
Most people are repulsed by leeches. But once you get past the fact that many species are parasitic bloodsuckers, you will discover that they are fascinating creatures with an important role in nature.
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About Aquatic Invertebrates in Missouri

Missouri's streams, lakes, and other aquatic habitats hold thousands of kinds of invertebrates — worms, freshwater mussels, snails, crayfish, insects, and other animals without backbones. These creatures are vital links in the aquatic food chain, and their presence and numbers tell us a lot about water quality.