Plethodus Dixon (Tselfatiiformes: Plethodidae) is an enigmatic Cretaceous bony fish genus characterized by circular or slightly oblong tooth plates and a short blunt rostrum. In this paper, two isolated rostral specimens attributable to Plethodus are described from the Britton Formation (Cenomanian-lower Turonian) of the Eagle Ford Group in Texas, U.S.A. This discovery, along with other recently described tselfatiiform fishes from the Britton Formation as well as isolated teeth and fragmentary bones of plethodids from the mid-late Cenomanian marine deposits, indicates that the radiation of tselfatiiform fishes in North America had already begun by the Cenomanian.