Middle Pleistocene Xenocyon lycaonoides Kretzoi, 1938 in northeastern China and the evolution of Xenocyon-Lycaon lineage

ABSTRACT

Xenocyon lycaonoides is a well-represented large canid known from the middle Early Pleistocene to Middle Pleistocene in Europe, central Asia, and Alaska, yet its fossil record in eastern Asia is extremely poor. Here we report a well-preserved palatal part of the skull of this species from Jinyuan Cave of Luotuo Hill, Puwan, Dalian of Liaoning Province, northeastern China. The new material confirms the presence of this species in eastern Asia during the early Middle Pleistocene, supporting a Holarctic distribution of this lineage during the Mid-Pleistocene climate change. The morphology of the new material suggests that the Middle Pleistocene X. lycaonoides is more derived than the late Early Pleistocene population, and is distinct from the living Lycaon pictus, and imply the different evolutionary direction from Lycaon. Our analyses support a generic distinction of the Xenocyon from Lycaon. X. lycaonoides can not be the direct ancestor of Lycaon, but is a related taxon that lived in Eurasia and North America. The lineage includes Xenocyon, and Lycaon Brookes, 1827, and partially contributes to Cynotherium Studiati, 1857, showing two independent Island specialisation events, making it one of the most successful lineages of canids ever known.

KEYWORDS:

• Xenocyon
• Jinyuan cave
• eastern Asia
• lycaon

Acknowledgments

We thank Prof. G. Koufos for providing the photos of the palate of Xenocyon lycaonoides from Apollonia 1. 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); A. Millhouse, D. Lunde, and J. J. Ososky (USNM fossil and modern mammal collections); M. Omura (MCZ modern mammal collections); and Z. Qiu and J. Chen, W. He, S. Chen, L. Zhang (fossil collections of the IVPP and HMV).

Disclosure statement

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

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Funding

[This work was supported by the Chinese Natural Science Foundation Program (grant No.41772018), Strategic Priority Research Program of Chinese Academy of Sciences (grant No. XDB26000000, XDA20070203, and XDB31030106), Second Tibetan Plateau Scientific Expedition and Research Grant (2019QZKK0705), special fund for excavation and repair of fossils, CAS, Administrative Committee of Dalian Puwan Economic Zone, Liaoning Province (The Comprehensive Research Project on Quaternary vertebrate fossils in Luotuo Hill from Dalian Puwan Economic Zone).