A huge Pachycrocuta from the middle pleistocene loess in Luoning County, central China, and the evolution of mandible within Pliocrocuta-Pachycrocuta lineage

ABSTRACT

The giant hyena Pachycrocuta is one of the iconic components in Eurasia Pleistocene faunas. This genus largely went extinct near the Early-Middle Pleistocene boundary in Europe, but continued to flourish till the early Middle Pleistocene in eastern Asia. However, the Middle Pleistocene Pachycrocuta in eastern Asia is only well represented in Loc. 1, 9 and 13 of Zhoukoudian, and the geographic variation is unknown. Here, a complete mandible is reported from the Middle Pleistocene loess in Luoning, Henan Province, central China. The mandible is similar to that of Pachycrocuta from Zhoukoudian in dental morphology, but is markedly larger, being the largest Pachycrocuta known (the estimated skull total length reaches 385 mm, and the estimated body mass is 150.3 kg). It also displays several unique mandibular traits, e.g., strongly curved toothrow, and elevated condyle. This suggests the presence of geographic or chronological differences between the populations of Pachycrocuta across Asia during the Middle Pleistocene. A gradually increasing depth is observed in the Pliocrocuta-Pachycrocuta lineage during its evolution, until its final extinction.

KEYWORDS:

• Giant hyena
• Quaternary
• eastern Asia
• mandible

Acknowledgments

We are thankful to J. Meng, R. O’Leary, J. Galkin, Z. Qiu, J. Chen, W. He, S. Chen, L. Zhang, L.F. Yang, Y.M. Cheng and Y.G. Jin (fossil collections of the AMNH, IVPP, HMV and GMC) for their help in accessing the fossil mammal collections under their care. The present study was supported by the Strategic Priority Research Program of Chinese Academy of Sciences (grant number XDB26000000 and XDA20070203), the Chinese Natural Science Foundation Program (grant number 42102001, 42002014 and 41772018), the Second Tibetan Plateau Scientific Expedition and Research Grant (2019QZKK0705) and the Administrative Committee of Dalian Jinpu New District, Liaoning Province (The Comprehensive Research Project on Quaternary vertebrate fossils from Luotuo Hill, Dalian).

Disclosure statement

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

Author contributions

Q. Jiangzuo, J. Liu and Y. Wang wrote the manuscript and performed the analysis; H. Jiang, collected and prepared the data.

Data availability

All data are present in the text.

Additional information

Funding

The present study is supported by Strategic Priority Research Program of Chinese Academy of Sciences [XDB26000000 and XDA20070203], the Chinese Natural Science Foundation Program [42102001 42002014 and 41772018], Second Tibetan Plateau Scientific Expedition and Research Grant [2019QZKK0705] Administrative Committee of Dalian Jinpu New District, Liaoning Province.