Field Guide

Aquatic Invertebrates

Showing 1 - 9 of 9 results
Media
Gray, speckled, translucent gelatinous blob cut in half to show structure
Species Types
Scientific Name
Freshwater species in the phylum Bryozoa
Description
Bryozoans are tiny, filter-feeding invertebrates. They create colonies that can be mossy, branching, or round and jellylike.
Media
Photo of caddisfly larva with case made of detritus
Species Types
Scientific Name
Various species in the order Trichoptera
Description
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.
Media
Photo of a horsehair worm in an aquarium
Species Types
Scientific Name
About 350 species scientifically described.
Description
Adult horsehair worms can be nearly 3 feet long and live in water. They are practically featureless, smooth, aquatic worms that writhe into knots and curls.
Species Types
Scientific Name
Various species in the genus Hydra
Description
We’ve all seen aquariums and pictures of tropical saltwater invertebrates such as corals, jellyfish and anemones—but did you know that there are similar creatures living in the freshwater habitats of Missouri?
Media
Photo of a leech
Species Types
Scientific Name
Various species in the subclass Hirudinea
Description
Who isn't repulsed by leeches! Yet once you get past the fact that many species are parasitic bloodsuckers, you will discover that they are fascinating creatures.
Media
Photograph of several mosquito larvae resting at water surface
Species Types
Scientific Name
There are about 50 species of mosquitoes in our state.
Description
The larvae of mosquitoes, often called “wrigglers,” have a large head and thorax and a narrow, wormlike abdomen; they typically hang just below the water surface. When disturbed, they wriggle downward.
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
Photo of a pink planarian on a rock.
Species Types
Scientific Name
Dugesia, Planaria, and other genera
Description
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.
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.