Field Guide

Aquatic Invertebrates

Showing 1 - 8 of 8 results
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
pond mussel
Species Types
Scientific Name
Bivalve molluscs in order Unionoida
Description
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.
Media
Photo of a ramshorn snail on a wet rock.
Species Types
Scientific Name
Gyraulus, Helisoma, Menetus, Micromenetus, Planorbula spp.
Description
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.
Media
Photo of backswimmer, side view
Species Types
Scientific Name
About 32 North American species in the family Notonectidae
Description
Sometimes called “water bees” or “water wasps,” backswimmers are predaceous and can deliver a painful bite if mishandled. True to their name, they swim belly-up, and their backs are keeled like a boat, which makes back-swimming easier.
Media
Photo of a spothanded crayfish viewed from above on white background.
Species Types
Scientific Name
About 38 species in Missouri
Description
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.
Media
Photo of an aquatic tubificid worm among rocks in an aquarium.
Species Types
Scientific Name
Tubifex spp. and other aquatic tubificid annelids
Description
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.
Media
Red midge fly larva, side view, in a petri dish
Species Types
Scientific Name
Nearly 1,100 species in North America
Description
Midge larvae look something like thin aquatic inchworms. They can be clear, whitish, olive, tan, or bright red. They occur in a variety of aquatic habitats. As adults, they resemble mosquitoes but they never bite.
Media
Water springtails congregate in water above soggy dead leaves
Species Types
Scientific Name
Podura aquatica
Description
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.
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.