A “buffalo (bison) lizard” from Late Cretaceous Montana. The name is based on Black Feet Indian eini, “buffalo” to honor the Black Feet tribe, on whose land in Montana the fossils were found, referring also to the idea that ceratopsians were the “buffalo” of the Cretaceous, living in large, socially complex herds. Named by paleontologist Scott Matthew Sampson in 1995.