Field Guide

Aquatic Invertebrates

Showing 1 - 10 of 27 results
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 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
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
Zebra Mussel
Species Types
Scientific Name
Dreissena polymorpha
Description
Zebra mussels are named for their shells, which have alternating light and dark bands. They are a highly invasive nonnative species. Learn how to prevent their spread.
Media
Photo of several prosobranch pond snails crawling on a rock.
Species Types
Scientific Name
Over 20 Missouri species in former subclass Prosobranchia
Description
Gilled snails are one of two main groups of aquatic snails in Missouri (the other group is the "lunged" snails). Gilled snails, or prosobranchs, breathe with gills and possess a hard trapdoor-like operculum. They are most common in the Ozarks.
Media
Photo of pulmonate snail crawling on rock
Species Types
Scientific Name
Over 30 Missouri species in former subclass Pulmonata
Description
Pulmonate, or lunged snails breathe via a lunglike pulmonary cavity, and they lack the hard trapdoor-like operculum found in gilled snails. Except for in the Ozarks, pulmonate snails predominate in most of the aquatic regions in our state.
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.
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
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 a dragonfly larva resting on a stone.
Species Types
Scientific Name
Species in the suborder Anisoptera
Description
Dragonfly larvae are aquatic insects with large eyes, six legs, and an oval or rounded segmented abdomen. The lower jaws are scooplike and cover much of the lower part of the head.
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.