Epioblasma walkeri

Epioblasma walkeri, common name the tan riffleshell, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.
Many scientists now recognize this mussel as synonymous or a subspecies of the presumed extinct Epioblasma florentina due to integrating shell characteristics between them.
At the time of its listing in 1977 under the Endangered Species [Act of 1973], its range was limited to the lower Red River, the middle fork of the Holston River, a possible population in the Stones River, the Duck River, where its population was threatened by a proposed Tennessee [Valley Authority] dam, and the Clinch River. The population in Indian Creek in the upper Clinch River basin was proposed as a separate subspecies by Jones, Neves, Ahlstedt and Hallerman in 2006.
It is listed under Appendix I of the Convention on International [Trade in Endangered Species of Wild Fauna and Flora].