Threatened Species Status for the Headwater Chub and a Distinct Population Segment of the Roundtail Chub

We, the U.S. Fish and Wildlife Service (Service), propose to list the headwater chub (Gila nigra) and a distinct population segment (DPS) of the roundtail chub (Gila robusta) from the lower Colorado River basin as threatened species under the Endangered Species Act (Act). If we finalize this rule as proposed, it would extend the Act's protections to this species and DPS.