''Plethobasus cooperianus'', the orange-footed pimpleback mussel or orangefoot pimpleback, is a rare species of freshwater mussel in the family Unionidae, the river mussels. This aquatic

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

mollusk is native to the Tennessee,

Cumberland Cumberland ( ) is a historic county in the far North West England. It covers part of the Lake District as well as the north Pennines and Solway Firth coast. Cumberland had an administrative function from the 12th century until 1974. From 19 ...

, and lower

Ohio River The Ohio River is a long river in the United States. It is located at the boundary of the Midwestern and Southern United States, flowing southwesterly from western Pennsylvania to its mouth on the Mississippi River at the southern tip of Illino ...

s in the United States, where its distribution has declined over 70%.''Plethobasus cooperianus''.
The Nature Conservancy. This rounded mussel grows up to 9.5 centimeters long by 7.8 wide by 4.6 high.USFWS
''Plethobasus cooperianus'' Recovery Plan.
September 1984. It has bumps on the posterior part of the shell and the foot is orange in live specimens. The mussel mainly lives in deep, fast-flowing rivers, especially with gravel or sand on the bottoms. It buries itself in the substrate under up to 29 feet of water.USFWS

Species Profile. This species was once common in some areas. It is now restricted for several reasons. Rivers throughout much of its range have been impounded. There has been an increase in silt, which the mussel cannot tolerate. Pollution of the waterways has led to the decline of this and other mussels. The zebra mussel (''Dreissena polymorpha'') is a widespread threat.

References

Molluscs of the United States cooperianus Bivalves described in 1834 ESA endangered species Taxonomy articles created by Polbot {{Unionidae-stub