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Reinvestigation of Yuanotherium minor and its implications for the cuspal homology and maxillary-palatal evolution of tritylodontids

  • LIU Lu ,
  • REN Ji-Cheng ,
  • MAO Fang-Yuan
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  • 1 National Natural History Museum of China Beijing 100050
    2 Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences Beijing 100044
    3 University of Chinese Academy of Sciences Beijing 100049
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Liu Lu and Ren Ji-Cheng contributed equally to this work and share the first authorship

Received date: 2025-02-27

  Online published: 2025-03-31

Copyright

Editorial board of Vertebrata Palasiatica, , ©The Author(s) 2025. This is an open access article under the CC BY-NC-ND License (https://creativecommons.org/licenses/by/4.0/).

Abstract

Several tritylodontid taxa have been reported from the Upper Jurassic of the Wucaiwan area in the Junggar Basin of Xinjiang, northwestern China, including Yuanotherium minor. The original study described the partially preserved postcanine teeth in the middle of the left upper maxilla. After detailed re-examination of the specimen and by CT scanning, 3D reconstruction, and scanning electron microscopy observations, we provided a more detailed description of the osteology, neurosensory, and tooth wear pattern for all the bones preserved in this specimen and clarified some characters. Based on new information about the cusp wear pattern, the chewing movement pattern of the dentition and detailed cusp morphology, we discussed the cuspal homology of upper cheek teeth of tritylodontids and postulate a standardized method for cusp identification. We hypothesize that the unique maxilla characteristics furnish the evidence for transitional stages about the evolution of the upper jaw-palate structure in tritylodontids.

Cite this article

LIU Lu , REN Ji-Cheng , MAO Fang-Yuan . Reinvestigation of Yuanotherium minor and its implications for the cuspal homology and maxillary-palatal evolution of tritylodontids[J]. Vertebrata Palasiatica, 2025 , 63(2) : 81 -101 . DOI: 10.19615/j.cnki.2096-9899.250331

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