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Reply to: Triassic sauropodomorph eggshell might not be soft

The Original Article was published on 19 October 2022

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Fig. 1: The geochemistry of Mussaurus eggshell.

Data availability

All relevant data are available in the paper and Supplementary Data 1 and 2, the original paper2 and ref. 12.

Code availability

R code used for the ancestral state reconstruction is available as Supplementary Code.


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We thank D. E. G. Briggs for helpful comments and edits. J. O’Connor and P. Heck offered laboratory and instrument access. A. Shinya prepared the new thin section and G. Olack helped to collect the elemental maps. I.M. was funded by project no. PGC2018-094955-A-I00 granted by the Spanish Ministerio de Ciencia, Innovación y Universidades.

Author information

Authors and Affiliations



J.W. collected and analysed in situ Raman microspectroscopy data, prepared Fig. 1 and wrote, together with D.K.Z., M.F. and I.M. the first draft of the manuscript. M.F. collected elemental maps and imaged the new thin section. I.M. performed the time-scaled ancestral state reconstruction and prepared Extended Data Fig. 1. All authors contributed to the discussion of the data and the final version of the manuscript.

Corresponding authors

Correspondence to Jasmina Wiemann, Iris Menéndez or Matteo Fabbri.

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Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data figures and tables

Extended Data Fig. 1 Time-scaled ancestral state reconstruction of diapsid eggshell evolution with the status of Mussaurus eggs changed to ‘hard-shelled’ despite evidence for its soft nature.

Time scaling of the tree2 (100 times) was performed in the R16 ‘paleotree’ package. Branch scaling: stratigraphic appearance of each taxon (minimum and maximum age); node calibration: minimum age of clade appearance. The consensus tree was calculated using consensus.edges in R ‘phytools’17. Model: maximum likelihood (ML: ace in ‘ape’18). fitdiscrete in the R package ‘geiger’19 was used to determine ARD (= all rates differ) as the best transition model (ER; SYM; ARD). Node numbers and state probabilities can be found in the Supplementary Data 2.

Supplementary information

Supplementary Data 1

All spectroscopy-related data.

Supplementary Data 2

Ancestral state reconstruction.

Supplementary Code

Source code containing the R script.

Reporting Summary

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Norell, M.A., Wiemann, J., Menéndez, I. et al. Reply to: Triassic sauropodomorph eggshell might not be soft. Nature 610, E11–E14 (2022).

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