Field Guide

Aquatic Invertebrates

Showing 1 - 10 of 42 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
Photo of a belted crayfish, also called Big River crayfish.
Species Types
Scientific Name
Faxonius harrisonii (formerly Orconectes harrisonii)
Description
The belted crayfish is medium-small, tan, with a distinctive pattern of alternating olive-green and reddish-brown bands on the abdominal segments. It is found only in the Big River and its tributaries.
Media
Photo of a Big Creek crayfish.
Species Types
Scientific Name
Faxonius peruncus (formerly Orconectes peruncus)
Description
The Big Creek crayfish is moderately small and brown. It has a very localized distribution centered in Big Creek and its tributaries, in the St. Francis River basin. It lacks bright colors, but blackish specks and blotches occur over the top surfaces of the body and pincers.
Media
Photo of a bristly cave crayfish, viewed from the side.
Species Types
Scientific Name
Cambarus setosus
Description
The bristly cave crayfish is a whitish crayfish with small, unpigmented eyes and long, slender pincers with noticeable setae (bristles). It lives in caves in the Springfield Plateau region of the Ozarks.
Media
Photo of a Cajun dwarf crayfish.
Species Types
Scientific Name
Cambarellus puer
Description
The Cajun dwarf crayfish is small, reddish brown to gray, with a paired series of dark, wavy stripes or dashes along the dorsal surface. In Missouri, it occurs in our southeastern lowlands.
Media
Photo of a papershell crayfish, also called calico crayfish.
Species Types
Scientific Name
Faxonius immunis (formerly Orconectes immunis)
Description
The calico crayfish is rather plain: gray-green with a pale central zone along the middle of the carapace and abdomen. The pincers are orange-tipped, and in mature males are tinged with purple. It is usually only found in the northern half of the state.
Media
Photo of a Caney Mountain cave crayfish out of water on a wet, red-coated cave rock.
Species Types
Scientific Name
Orconectes stygocaneyi
Description
One of three species of cave crayfish in Missouri, the Caney Mountain cave crayfish is known from only one location. Like many other cave invertebrates, this species is whitish and is blind.
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
Photo of a coldwater crayfish.
Species Types
Scientific Name
Faxonius eupunctus (formerly Orconectes eupunctus)
Description
The coldwater crayfish has a very localized distribution in the Eleven Point River system. It is stout, with a blue-green head and pincers and dark, rust-brown carapace. It is an imperiled species.
Media
Photo of a spothanded crayfish viewed from above on white background.
Species Types
Scientific Name
About 36 species in Missouri
Description
Crayfish are freshwater aquatic invertebrates that look a lot like small lobsters, to which they are related. There are about 36 species of crayfish in Missouri.
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.