Field Guide

Aquatic Invertebrates

Showing 1 - 10 of 18 results
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
Two pairs of Asian clam shells, still hinged together, showing exterior and interior
Species Types
Scientific Name
Corbicula fluminea
Description
The Asian clam is a nonnative, invasive species that lives in a variety of aquatic habitats. It has thick shells with distinctly ridged, concentric rings and a yellowish-brown to dark brown shell covering.
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
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
Clam shrimp on a white fabric surface
Species Types
Scientific Name
Cyclestherida, Laevicaudata, and Spinicaudata (orders or suborders)
Description
Clam shrimp have their carapace shaped like a pair of clam shells and they can close it tightly when disturbed. But they are not clams: they have tiny, jointed shrimplike legs and bristly, feathery antennae.
Media
Fingernail clam in a person’s hand
Species Types
Scientific Name
Pisidium, Sphaerium, and Musculium spp.
Description
Fingernail clams, also called pill clams or pea clams, are members of a family of small to tiny freshwater clams that are common but rarely noticed. They occur in a variety of aquatic habitats.
Media
Photo of a freshwater jellyfish
Species Types
Scientific Name
Craspedacusta sowerbii (syn. C. sowerbyi)
Description
You may have heard about stinging jellyfish in the ocean, but did you know that there are similar creatures living in the freshwater of Missouri? Fortunately, they’re harmless!
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.
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 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.
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.