Grey-Speckled Crayfish-Orconectes palmeri (Faxon)

This crayfish is gray with numerous greenish-black speckles and blotches on the pincers, carapace and abdomen. A pair of large blotches are present near the back of the head, and another pair occur near the junction of the carapace and abdomen. The fingers often have conspicuous cream-yellow tips. The carapace is not separated at its middle by a space (areola). Adults are about 1.4 to 2.6 inches in length.

This crayfish occurs widely in the Lowlands of southeastern Missouri and penetrates into adjacent sections of the Ozarks along the major streams. It is restricted to permanent-flowing waters, occurring among tree roots and organic debris, and beneath roots.

The gray-speckled crayfish is the only common Orconectes in the Lowlands. Other typical crayfish of the region have longer, more slender pincers, and none have the pattern of dark paired blotches described above.

Article Source:

http://mdc.mo.gov/nathis/arthopo/crayfish/varcraw.htm#anchor1223529