Appalachian brook crayfish, Cambarus bartonii cavatus, at the Crayfish lab in West Liberty University in West Liberty, WV.
This specimen is from Ohio.
The black on this animal is manganese that has encrusted all over its body. Manganese is a pollutant from coal mining runoff in rivers and streams. Crayfish and mussels are often killed by the toxic sediments that cover the bottoms of rivers downstream from coal mines. Stream sedimentation is the number one cause of crayfish imperilment, and crayfish are the fourth most imperiled animal group on the planet.