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Triassic sauropodomorph eggshell might not be soft

Nature volume 610, pages E8–E10 (2022)Cite this article

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Matters Arising to this article was published on 19 October 2022

The Original Article was published on 17 June 2020

arising from M. A. Norell et al. Nature https://doi.org/10.1038/s41586-020-2412-8 (2020)

The fossil record of dinosaur eggs is highly biased; in contrast to the relatively rich egg record for theropods and sauropodomorphs1,2, the characteristics of ceratopsian eggs have remained unknown because of an absence of embryo-containing eggs. On the basis of well-preserved Protoceratops (Ceratopsia) and Mussaurus (Sauropodomorpha) eggs, Norell et al.3 suggested a new hypothesis: the first dinosaur eggs were soft and, therefore, extremely dissimilar to the rigid eggs of Cretaceous dinosaurs; and rigid eggshells were independently acquired by theropods, sauropodomorphs and ornithopods. Although we acknowledge that this hypothesis is a practical working hypothesis and may eventually be proved true, the interpretation of a ‘soft Mussaurus eggshell’3 is uncertain, and may undermine their conclusion and mislead the interpretations of other fossil eggshells. The interpretation of a ‘soft Mussaurus eggshell’, therefore, requires a rigorous verification based on a solid understanding of the biomineralization of Mussaurus eggshell.

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Fig. 1: Analytical data from modern and fossil eggshells.
Fig. 2: Likelihood based an ancestral character reconstruction for eggshell mechanical properties in Diapsida.

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No new data were generated in this study.

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Acknowledgements

We thank J. Nan for discussion. S.C. was supported by a Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education (grant number 2020R1A6A3A03038316); T.-R.Y. was supported by research funding from the Ministry of Science and Technology, Taiwan (MOST 108-2116-M-178-003-MY2); M.M.-A. was supported by Fundação para a Ciência e a Tecnologia (PTDC/CTA-PAL/31656/2017 and SFRH/BPD/113130/2015) and the Spanish Ministry of Science and Innovation (project CGL2017-85038-P) and by the Government of Aragón-FEDER 2014–2020.

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Author notes

  1. Noe-Heon Kim

    Present address: Department of Geosciences, Princeton University, Princeton, NJ, USA

Authors and Affiliations

  1. Department of Earth Sciences, Montana State University, Bozeman, MT, USA

    Seung Choi

  2. Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China

    Seung Choi & Shukang Zhang

  3. Department of Geology, National Museum of Natural Sciences, Taichung, Taiwan

    Tzu-Ruei Yang

  4. Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan

    Tzu-Ruei Yang

  5. Aragosaurus: Recursos Geológicos y Paleoambientes – IUCA, Universidad de Zaragoza, Zaragoza, Spain

    Miguel Moreno-Azanza

  6. Geobiotec, Departamento de Ciências da Terra, Universidade Nova de Lisboa, Caparica, Portugal

    Miguel Moreno-Azanza

  7. Espaço Nova Paleo, Museu da Lourinhã, Lourinhã, Portugal

    Miguel Moreno-Azanza

  8. Department of Geosciences, Seoul National University, Seoul, South Korea

    Noe-Heon Kim

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All of the authors conceived, wrote and edited the manuscript.

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Correspondence to Seung Choi.

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Choi, S., Yang, TR., Moreno-Azanza, M. et al. Triassic sauropodomorph eggshell might not be soft. Nature 610, E8–E10 (2022). https://doi.org/10.1038/s41586-022-05151-9

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