First record of Cricetops rodent in the Oligocene of southwestern China

Abstract

The muroid Cricetops Matthew and Granger, 1923 commonly occurred in the Oligocene terrestrial deposits in central and northern Asia. Here we report the first record of Cricetops in the southern part of Asia. Isolated rodent molars named as a new species, Cricetops auster sp. nov., were discovered from the early Oligocene sediments at the Lijiawa locality in Yunnan Province in southwestern China. Compared to previously known Cricetops, C. auster is smaller than Cricetops dormitor Matthew and Granger, 1923 and Cricetops aeneus Shevyreva, 1965, but larger than Cricetops minor Wang, 1987. The cusps of C. auster are less conical. The ridges and crests are longer, higher and thicker. Relatively long and high crests, ridges and arms extending from the main cusps in the new species make those cusps more crescent in appearance than in C. dormitor, C. aeneus and C. minor. C. auster is a rare species in the Lijiawa mammalian fauna. Well-developed shearing tooth crests and ridges of C. auster probably suggest a different diet from the Cricetops from the northern part of Asia.

Keywords:

• Cricetops
• Oligocene
• southwestern China
• rodents

Acknowledgement

We thank Zhouliang Yan, Guizhen Wang, Ran Li and Ge Li for their assistance in the field. We thank Yemao Hou for performing the CT scanning. We thank Dr Lawrence J. Flynn and Prof. Pierre Mein for instructive comments and English editing.