A cranium of Bison alaskensis (Mammalia: Artiodactyla: Bovidae) and comments on fossil Bison diversity in the American Falls area, southeastern Idaho

ABSTRACT

A change in repository is noted and a complete description is given for IMNH 714/40119, a partial Bison alaskensis cranium collected in 1894 along the Snake River in the vicinity of American Falls. This specimen, the first documented fossil from the American Falls local fauna, is morphologically distinct from the larger-horned B. latifrons and the shorter-horned B. priscus, both of which are also found in southeastern Idaho. It and other specimens of B. alaskensis from late Pleistocene sediments in the American Falls area demonstrate a morphologic canalization of the species and document that a substantial population of B. alaskensis inhabited southeastern Idaho. A stratigraphie review of Bison material from the American Falls area suggests that as many as four species of Bison inhabited Idaho during the late Rancholabrean and that both B. latifrons and B. alaskensis survived well into the late Pleistocene.