Calico Crayfish

Orconectes immunis
Cambaridae (freshwater crayfish) in the order Decapoda (shrimp, crabs and lobsters)

This rather plain, gray-green crayfish is characterized by a pale central zone along the middle of the carapace and abdomen. The pincers are orange-tipped, and in mature males are uniquely tinged with purple. The rostrum is without lateral notches or spines near its tip.

The calico crayfish superficially resembles the virile (or “Northern”) crayfish, and sometimes occurs in the same habitats. The latter species does not have a pale zone along the middle of the carapace and abdomen, and the rostrum has lateral notches or spines near its tip.

Adult length: about 1 3/4 to 3 1/2 inches.
Habitat and conservation: 
The calico crayfish (also called the papershell crayfish) occurs widely in the Prairie Region and along the floodplains of the Mississippi and Missouri rivers. It is almost always found over a mud bottom in turbid waters that fluctuate drastically in area and depth. Typical habitats are shallow sloughs and the isolated pools of prairie creeks. This crayfish retreats to burrows in late summer as the habitats in which it occurs dry up.
Crayfish are generally omnivores, eating a wide variety of plant and animal materials.
Distribution in Missouri: 
Mostly found in northern Missouri north of the Missouri River.
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