Field Guide

Aquatic Invertebrates

Showing 1 - 8 of 8 results
Media
Photo of an aquatic isopod in an aquarium, crawling on a rock.
Species Types
Scientific Name
Freshwater members of the crustacean order Isopoda
Description
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.
Media
Clam shrimp on a white fabric surface
Species Types
Scientific Name
Cyclestherida, Laevicaudata, and Spinicaudata (orders or suborders)
Description
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.
Media
Photo of a spothanded crayfish viewed from above on white background.
Species Types
Scientific Name
About 36 species in Missouri
Description
Crayfish are freshwater aquatic invertebrates that look a lot like small lobsters, to which they are related. There are about 36 species of crayfish in Missouri.
Media
Photo of a gravid Mississippi grass shrimp in an aquarium.
Species Types
Scientific Name
Palaemonetes kadiakensis
Description
Of Missouri’s two species of freshwater shrimp, the Mississippi grass shrimp is by far the most common and widespread.
Media
Photo of amphipod on a rock
Species Types
Scientific Name
Species in the crustacean order Amphipoda
Description
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.
Media
Photo of a northern, also called virile, crayfish.
Species Types
Scientific Name
Faxonius virilis (formerly Oronectes virilis)
Description
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.
Media
Photo of a water nymph crayfish, side view of specimen carefully arranged against black background
Species Types
Scientific Name
Faxonius nais (formerly Orconectes nais)
Description
The water nymph crayfish is normally found in streams but can also be found in a variety of other aquatic habitats. It is greenish brown or brown with no prominent markings. Its known distribution in Missouri is spotty.
Media
Photo of a White River crawfish.
Species Types
Scientific Name
Procambarus acutus
Description
Adult White River crawfish are usually a deep burgundy red with a black V-shaped stripe on the abdomen. Juveniles are gray with dark spots scattered over the carapace. In Missouri, this species mostly occurs in the Bootheel and north along the Mississippi River.
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.