Letter | Published:

Large Mesozoic mammals fed on young dinosaurs

Nature 433, 149–152 (13 January 2005) | Download Citation

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Abstract

Mesozoic mammals are commonly portrayed as shrew- or rat-sized animals that were mainly insectivorous, probably nocturnal and lived in the shadow of dinosaurs1,2,3,4,5. The largest known Mesozoic mammal represented by substantially complete remains is Repenomamus robustus, a triconodont mammal from the Lower Cretaceous of Liaoning, China6,7. An adult individual of R. robustus was the size of a Virginia opossum. Here we report a new species of the genus, represented by a skeleton with most of the skull and postcranium preserved in articulation. The new species is 50% larger than R. robustus in skull length. In addition, stomach contents associated with a skeleton of R. robustus reveal remains of a juvenile Psittacosaurus, a ceratopsian dinosaur. Our discoveries constitute the first direct evidence that some triconodont mammals were carnivorous and fed on small vertebrates, including young dinosaurs, and also show that Mesozoic mammals had a much greater range of body sizes than previously known. We suggest that Mesozoic mammals occupied diverse niches and that some large mammals probably competed with dinosaurs for food and territory.

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Acknowledgements

We thank M.-M. Chang, Z.-H. Zhou, X.-L. Wang, X. Xu, F.-C. Zhang, Y. Wang, F. Jin and J.-Y. Zhang for help coordinating the research and fieldwork; X. Xu, X.-L. Wang, F.-C. Zhang, Z.-H. Zhou, and M. Norell for discussions on the research subject, and S.-H. Xie, S.-J. Li and A. Davidson for specimen preparation. This work was supported by funding from the Chinese Ministry of Science and Technology, the National Natural Science Foundation of China and the Chinese Academy of Sciences. Y.H. is also supported by a fellowship from the American Museum of Natural History, through the City University of New York.

Author information

Affiliations

  1. Institute of Vertebrate Paleontology & Paleoanthropology, Chinese Academy of Sciences, PO Box 643, Beijing 100044, China

    • Yaoming Hu
    • , Yuanqing Wang
    •  & Chuankui Li

  2. Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York City, New York 10024, USA

    • Yaoming Hu
    •  & Jin Meng

  3. Biology Program, Graduate School and City College of New York, City University of New York, New York City, New York 10016, USA

    • Yaoming Hu

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Competing interests

The authors declare that they have no competing financial interests.

Corresponding author

Correspondence to Yaoming Hu.

Supplementary information

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    Supplementary Information Notes

    This Supplementary Information text includes: (I) body mass estimation for two species of Repenomamus; (II) stomach content preparation and identification for R. robustus (IVPP V 13605); (III) Data sources for Figure 4 (sizes of the lower jaws of representative Mesozoic mammals and relatives). The file contains six figures.

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https://doi.org/10.1038/nature03102

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