Field Guide

Aquatic Invertebrates

Showing 1 - 10 of 22 results
Photo of caddisfly larva with case made of detritus
Caddisfly Larvae
About 1,500 species in North America north of Mexico
The aquatic larvae of caddisflies are famous for building portable, protective cases out of local materials, including grains of sand, bits of leaves and twigs, and other debris. The adults are mothlike.
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.
Photo of a pink planarian on a rock.
Turbellarians (Planarians; Free-Living Flatworms)
Dugesia, Planaria, and other genera
Unlike their parasitic cousins in the flatworm group, turbellarians, or planarians, are tiny carnivores or detritus-eaters that glide smoothly across submerged leaves and other objects.
Photo of two water penny beetles clinging to a wet rock.
Water Penny Beetle Larvae
Beetles in the family Psephenidae
Water penny beetle larvae are truly nifty aquatic invertebrates that bring out the child in all of us. Some of them really do look like pennies!
Photo of a woodland crayfish.
Woodland Crayfish
Faxonius hylas (formerly Orconectes hylas)
The woodland crayfish is stout, reddish tan to dark brown, with numerous blackish specks and blotches on the pincers, carapace, and abdomen. It occurs only in Missouri, especially in the Black River and its tributaries.
Photo of a saddleback crayfish.
Saddleback Crayfish
Faxonius medius (formerly Orconectes medius)
The saddleback crayfish has a bold blackish band across the hind margin of the carapace and lacks dark blotches or specks. The pincers are broad and powerful. It occurs in the Big and Meramec river drainages.
Photo of a ringed crayfish.
Ringed Crayfish
Faxonius neglectus (formerly Orconectes neglectus)
The ringed crayfish is olive green to reddish tan and usually has black or brown rings around the pincer tips. In Missouri it is found in clear, rocky Ozark streams in the southwestern quarter.
Photo of a vernal crayfish.
Vernal Crayfish
Procambarus viaeviridus
Adult vernal crayfish are rusty red with a blackish wedge-shaped central stripe along the length of the abdomen. In Missouri, this species occurs only in our southeastern swamps and is usually only seen in February and March.
Photo of a spothanded crayfish viewed through creekwater.
Spothanded Crayfish
Faxonius punctimanus (formerly Orconectes punctimanus)
The spothanded crayfish is moderately large and usually has a noticeable black spot on each pincer near the base of the movable finger. In Missouri, it is found mostly in Ozark waterways in the southeastern quarter of the state, from Callaway, Montgomery, and Warren counties south.
giant floater
Giant Floater
Pygandon grandis
When a floater dies, this large mussel with a thick shell will actually rise to the water surface and float as it decays.
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.