Field Guide

Aquatic Invertebrates

Showing 1 - 10 of 36 results
Media
Photo of a St. Francis River crayfish.
Species Types
Scientific Name
Faxonius quadruncus (formerly Orconectes quadruncus)
Description
The St. Francis River crayfish is rather small and dark brown, with blackish blotches or specks over the upper surfaces of the pincers, carapace, and abdomen. It is limited to the St. Francis River and its tributaries.
Media
Photo of a woodland crayfish.
Species Types
Scientific Name
Faxonius hylas (formerly Orconectes hylas)
Description
The woodland crayfish is stout, reddish tan to dark brown, with numerous blackish specks and blotches on the pincers, carapace, and abdomen. It occurs only in Missouri, especially in the Black River and its tributaries.
Media
Photo of a freckled crayfish.
Species Types
Scientific Name
Cambarus maculatus
Description
The freckled crayfish is powerfully built, yellowish tan, with numerous conspicuous black spots on its pincers, carapace, and abdomen. It is largely restricted to the Courtois Hills section of the Meramec River basin.
Media
Photo of a gray-speckled crayfish.
Species Types
Scientific Name
Faxonius palmeri (formerly Orconectes palmeri)
Description
The gray-speckled crayfish is gray with numerous greenish-black speckles and blotches. A pair of large blotches are present near the back of the head, and another pair occur where the carapace joins the abdomen. In Missouri, it is found only in the southeastern section.
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 saddleback crayfish.
Species Types
Scientific Name
Faxonius medius (formerly Orconectes medius)
Description
The saddleback crayfish has a bold blackish band across the hind margin of the carapace and lacks dark blotches or specks. The pincers are broad and powerful. It occurs in the Big and Meramec river drainages.
Media
Photo of a ringed crayfish.
Species Types
Scientific Name
Faxonius neglectus (formerly Orconectes neglectus)
Description
The ringed crayfish is olive green to reddish tan and usually has black or brown rings around the pincer tips. In Missouri it is found in clear, rocky Ozark streams in the southwestern quarter.
Media
Photo of a golden crayfish viewed through the surface of creek water.
Species Types
Scientific Name
Faxonius luteus (formerly Orconectes luteus)
Description
The golden crayfish varies in color from olive green to golden yellow. Many body parts are trimmed with red. A dark band crosses the head just in front of the cervical groove, and another crosses the carapace at its junction with the abdomen. It's a wide-ranging species.
Media
Photo of a White River crawfish.
Species Types
Scientific Name
Procambarus acutus
Description
Adult White River crawfish are usually a deep burgundy red with a black V-shaped stripe on the abdomen. Juveniles are gray with dark spots scattered over the carapace. In Missouri, this species mostly occurs in the Bootheel and north along the Mississippi River.
Media
Photo of a vernal crayfish.
Species Types
Scientific Name
Procambarus viaeviridus
Description
Adult vernal crayfish are rusty red with a blackish wedge-shaped central stripe along the length of the abdomen. In Missouri, this species occurs only in our southeastern swamps and is usually only seen in February and March.
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.