Threatened Species Status With Section 4(d) Rule for Western Fanshell and ‘‘Ouachita’’ Fanshell and Designation of Critical Habitat

We, the U.S. Fish and Wildlife Service (Service), propose to list the western fanshell (Cyprogenia aberti), a freshwater mussel species from Arkansas, Kansas, Missouri, and Oklahoma, and the "Ouachita" fanshell (Cyprogenia cf. aberti), a freshwater mussel species from Arkansas and Louisiana, as threatened species and to designate critical habitat for these species under the Endangered Species Act of 1973, as amended (Act). This document also proposes a rule issued under section 4(d) of the Act (4(d) rule) for these mussel species and serves as our 12-month finding on a petition to list the western fanshell. The proposed critical habitat designation for the western fanshell totals approximately 360 river miles (579 kilometers), all of which are occupied by the species, in Arkansas, Kansas, and Missouri, and the proposed critical habitat designation for the "Ouachita" fanshell totals approximately 294 river miles (474 kilometers), all of which are occupied by the species, in Arkansas. We also announce the availability of a draft economic analysis (DEA) of the proposed designation of critical habitat for the western fanshell and "Ouachita" fanshell. If we finalize this rule as proposed, it would add these species to the List of Endangered and Threatened Wildlife and extend the Act's protections to these species and their designated critical habitats.