Field Guide

Aquatic Invertebrates

Showing 1 - 10 of 21 results
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
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 a mayfly naiad crawling on rock underwater
Species Types
Scientific Name
There are hundreds of species in North America.
Description
Mayfly larvae, or nymphs, live from months to years under water, breathing through gills, and the adults fly around in the air, mating, living for only a day or two.
Media
Photo of a stonefly naiad clinging to a rock underwater
Species Types
Scientific Name
There are hundreds of species in North America
Description
Stonefly larvae are aquatic and somewhat resemble the larvae of mayflies and damselflies. Their presence usually indicates good water quality.
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 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
pink mucket
Species Types
Scientific Name
Lampsilis abrupta
Description
This endangered native mussel lives in flowing waters of large streams among gravel and cobble.
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.
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.