Dental shape evolution of the giant panda (Ailuropoda, Ursidae) during the Quaternary

ABSTRACT

The giant panda is well known to have unique dentition, adapted to bamboo exclusive diet. The teeth are used to cut and grind the bamboo. However, it is unclear how these teeth evolved through geographical time. Here, we present the first geometric morphometric analysis of all cheek teeth of the giant panda, based on the large fossil collection of the giant panda teeth found from the Pleistocene deposits of southern China. Our analyses reveal the substantial intraspecific variation of the giant panda teeth, but no significant interspecific differences in Ailuropoda, supporting the basic function of the giant panda teeth has already formed since the Early Pleistocene. Among the cheek teeth, the premolars show the highest interspecific variation, suggesting a continuous increase in the feeding efficiency of the bamboo diet, which may facilitate the giant panda to grow a larger body size from Early Pleistocene species to A. melanoleuca. The Late Pleistocene A. m. baconi and two modern two subspecies show largely overlapped morphospace for all teeth, and the variation ranges are also similar, suggesting a fully established feeding apparatus and implying a similar diet. Our analyses provide new information on the giant panda evolution and adaptation.

KEYWORDS:

• Ailuropoda microta
• Ailuropoda wulingshanensis
• Ailuropoda melanoleuca baconi
• Gigantopithecus Cave
• Pleistocene
• geometric morphometry

Acknowledgments

The authors thank the Second Comprehensive Scientific Expedition on the Tibetan Plateau for providing financial and logistical support in the fieldwork. The authors are grateful to M. Surovy, E. Hoeger and S. Ketelsen for their help in accessing the AMNH modern mammal collections; J. Chen and H. Si for accessing the IVPP fossil mammal collection; X. Zhu and Y. Yang in IOZ mammal collection; X. Jiang, L. Liu, Q. Li in KIZ mammal collection, H. Gong in FP mammal collection.

Disclosure statement

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

Additional information

Funding

The present study is supported by the National Key Research and Development Program of China (No. 2023YFF0804501) and Chinese Natural Science Foundation Program (grant numbers 42102001, 42262001, 32100489).