Field Guide

Aquatic Invertebrates

Showing 1 - 10 of 13 results
Media
Photo of a St. Francis River crayfish.
Species Types
Scientific Name
Faxonius quadruncus (formerly Orconectes quadruncus)
Description
The St. Francis River crayfish is rather small and dark brown, with blackish blotches or specks over the upper surfaces of the pincers, carapace, and abdomen. It is limited to the St. Francis River and its tributaries.
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.
Media
Photo of a red swamp crawfish or crayfish.
Species Types
Scientific Name
Procambarus clarkii
Description
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.
Media
Photo of a Shufeldt’s dwarf crayfish.
Species Types
Scientific Name
Cambarellus shufeldtii
Description
Shufeldt’s dwarf crayfish is small, reddish brown to gray, with a paired series of dark, wavy stripes or dashes along the dorsal surface. In Missouri, it occurs in our southeastern lowlands and north along the Mississippi River floodplain.
Media
Photo of a shrimp crayfish.
Species Types
Scientific Name
Faxonius lancifer (formerly Orconectes lancifer)
Description
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.
Media
Photo of a Cajun dwarf crayfish.
Species Types
Scientific Name
Cambarellus puer
Description
The Cajun dwarf crayfish is small, reddish brown to gray, with a paired series of dark, wavy stripes or dashes along the dorsal surface. In Missouri, it occurs in our southeastern lowlands.
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 a leech
Species Types
Scientific Name
Various species in the subclass Hirudinea
Description
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.
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.
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.