Field Guide

Aquatic Invertebrates

Showing 1 - 6 of 6 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 a red swamp crawfish or crayfish.
Red Swamp Crawfish
Procambarus clarkii
Adult red swamp crawfish are dark red (nearly black on the carapace) and have a wedge-shaped black stripe on the abdomen. Juveniles are a uniform gray, sometimes overlain by dark wavy lines. In Missouri it lives in the Bootheel.
Photo of a shrimp crayfish.
Shrimp Crayfish
Faxonius lancifer (formerly Orconectes lancifer)
The shrimp crayfish is medium-small, light reddish brown to gray, and thickly dusted with darker specks. Its noselike rostrum is unusually long, with the tip longer than the base, and the pincers are narrow and weak. It is found in the Bootheel.
Photo of amphipod on a rock
Scuds and Sideswimmers (Amphipods)
Species in the crustacean order Amphipoda
Often overlooked by people, but eagerly sought by fish, Missouri’s amphipods resemble shrimplike sowbugs. Scuds live in various aquatic habitats, and several species inhabit caves.
Photo of an aquatic isopod in an aquarium, crawling on a rock.
Aquatic Pillbugs and Sowbugs (Aquatic Isopods)
Freshwater members of the crustacean order Isopoda
Everyone knows about terrestrial sowbugs and pillbugs, but many isopod species are aquatic. Missouri has several isopods that live in streams, ponds, rivers, and caves.
Clam shrimp on a white fabric surface
Clam Shrimp
Cyclestherida, Laevicaudata, and Spinicaudata (orders or suborders)
Clam shrimp have their carapace shaped like a pair of clam shells and they can close it tightly when disturbed. But they are not clams: they have tiny, jointed shrimplike legs and bristly, feathery antennae.
See Also

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.