Early Pleistocene Equus community from Jinyuan Cave, Luotuo Hill in Dalian, Northeast China and its palaeoecological significance

ABSTRACT

Early Pleistocene Equus specimens collected from Jinyuan Cave, Luotuo Hill, Dalian, have been described. The newly reported specimens include two forms. The large-sized form is identified as E. sanmeniensis. The small-sized form is identified as E. teilhardi. E. sanmeniensis shares highly similar features with another huge-sized species E. wangi. Based on further comparison of the new and classic specimens of E. sanmeniensis, the differences between these two species are more obvious. For now, Early Pleistocene Equus in Jinyuan Cave includes E. sanmeniensis, E. teilhardi and E. qingyangensis, same as the composition of Nihewan fauna (s.s.) in Hebei and similar to Bajiazui fauna in Gansu. Among Early Pleistocene Equus in China, medium-sized forms are wide distributed, while distributions of large-sized form are relatively limited, and this is likely relative to difference of adaptability. From Early to Late Pleistocene, Equus community seemed to keep in a pattern of one large-sized species accompanied with two medium-sized species with slender and robust limbs, respectively. This pattern had occurred since around 2.1 Ma, likely established during the second immigration event of Equus from North America to Eurasia.

KEYWORDS:

• Equus
• Jinyuan cave
• early Pleistocene
• palaeoecology
• paleozoogeography

Acknowledgments

The editor Dr. Dyke and two reviewers greatly improved the manuscript and figures. Dr. Guillaume Billet provided access to observations on type specimens of the Nihewan fauna housed in MNHN. Ms. Judy Galkin provided access to observations on specimens of the Equus specimens housed in American Museum of Natural History. Dr. Yuan Wang improved our manuscript. Mr. Sheng Lü, Mses. Yayun Song and Jie Zhang provided support to observations on Jinyuan Cave specimens housed in Administrative Committee of Dalian Jinpu New District. Ms. Sizhao Liu provided support on Dalian Equus specimens housed in DNHM for comparison. We appreciate for all of their efforts.

Disclosure statement

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

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geologyand Palaeontology, CAS) (No. 203115), the National Natural Science Foundation of China (grant number 41872022), and Administrative Committee of Dalian JinpuNew District, Liaoning Province (The Comprehensive Research Project onQuaternary vertebrate fossils from Luotuo Hill, Dalian); the Strategic PriorityResearch Program of the Chinese Academy of Sciences (XDB26030302, XDA20070203),award of Youth Innovation Promotion Association, Chinese Academy of Sciences(2021069).