 The species "B. acutifrons" first appeared in the early Pleistocene, some 2.58 million years ago at the earliest, and died out around 1 million years ago.Duvernois in 1990 proposed it evolved directly from an Indian species of "Leptobos", perhaps "L. falconeri", along with the Pleistocene genera or subgenera "Bison" and "Bibos".Martínez-Navarro "et al".