Bensonomys, Calomys, and the Origin of the Phyllotine Group of Neotropical Cricetines (Rodentia: Cricetidae)

Abstract

The Late Miocene to Pleistocene North American genus Bensonomys is recognized as a subgenus of the Pleistocene and Recent South American genus Calomys. Two new species of Calomys are described from the Hemphillian White Cone fauna of Arizona. Characters of this older material indicate that Calomys is derived from Copemys, the cricetine which is also ancestral to Peromyscus. The phyllotine group of South American cricetines initially evolved in North America and did not enter South America until the Panamanian land bridge was established, in the latest Pliocene or earliest Pleistocene.