New material of Amphicyon zhanxiangi from laogou, linxia basin suggests a possible southern dispersal with increasing omnivory

ABSTRACT

The fossil records of large amphicyonids in Asia are rare and fragmentary, and their evolution and dispersal are also unclear. Here we present new dental material from Laogou, Linxia Basin, Gansu Province, belonging to the Hujialiang Formation, Middle Miocene. The new material is very similar to Amphicyon zhanxiangi from the Dingjia’ergou fauna of the Zhang’enbao Formation, Tongxin, Ningxia, and can be referred to this species. It is younger than the Tongxin material and differs from the latter by having better-distinguished cusps in upper molars, supporting this species is probably the ancestor to the omnivorous Arctamphicyon found in the Siwaliks, Yuanmou, and the Lower Irrawaddy. This lineage might immigrate to southern and southeastern Asia by the Late Miocene, and adapted to an increasing omnivorous diet due to more available plant material in tropical and subtropical regions.

KEYWORDS:

• Linxia Basin
• Laogou
• Amphicyon
• Arctamphicyon
• Miocene

Acknowledgments

For their help in accessing collections, we thank J. Meng, R. O’Leary, and J. Galkin (AMNH fossil mammal collections); M. Surovy, E. Hoeger, and S. Ketelsen (AMNH modern mammal collections) and Z. Qiu and J. Chen, W. He, S. Chen, L. Zhang (fossil collections of the IVPP and HMV). The current work was supported by the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB26000000, XDA20070203, and XDB31030106), Key Frontier Science Research Program of the Chinese Academy of Sciences (Grant Nos. QYZDY-SSW-DQC-22 and GJHZ1885), the National Natural Science Foundation of China (Grant Nos. 41430102, 41872001, 41872005 and 41772018).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [41430102, 41872001, 41872005 and 41772018]; Strategic Priority Research Program of Chinese Academy of Sciences [XDB26000000, XDA20070203, and XDB31030106]; Key Frontier Science Research Program of the Chinese Academy of Sciences [QYZDY-SSW-DQC-22 and GJHZ1885]; Second Tibetan Plateau Scientific Expedition and Research [2019QZKK0705].