Field Guide

Aquatic Invertebrates

Showing 1 - 10 of 13 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 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
elktoe
Species Types
Scientific Name
Alasmidonta marginata
Description
The elktoe is one of many Missouri mussels with a declining population.
Media
fragile papershell
Species Types
Scientific Name
Leptodea fragilis
Description
A widespread mussel that relies on freshwater drum as host fish for the developing young.
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
giant floater
Species Types
Scientific Name
Pygandon grandis
Description
When a floater dies, this large mussel with a thick shell will actually rise to the water surface and float as it decays.
Media
mucket
Species Types
Scientific Name
Actinonaias ligamentina
Description
One of the most widespread and numerous mussels in southern Missouri.
Media
pink heelsplitter
Species Types
Scientific Name
Potamilus alatus
Description
A large dorsal wing and purple lining make identification of this widespread mussel easy.
Media
plain pocketbook
Species Types
Scientific Name
Lampsilis cardium
Description
The plain pocketbook is one of the most common and widespread mussels in our state. It is oval, relatively large, and occurs frequently.
Media
round pigtoe
Species Types
Scientific Name
Pleurobema sintoxia
Description
Round pigtoes are more rounded than Wabash pigtoes. Usually, the nacre (the shell lining) is white, but in rare individuals it is bright pink.
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.