This is a preview of subscription content, access via your institution
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Code availability
R code used for the ancestral state reconstruction is available as Supplementary Code.
References
Choi, S., Yang, T.-R., Moreno-Azanza, M., Zhang, S. & Kim, N.-H. Triassic sauropodomorph eggshell might not be soft. Nature https://doi.org/10.1038/s41586-022-05151-9 (2022).
Norell, M. A. et al. The first dinosaur egg was soft. Nature 583, 406–410 (2020).
Buseck, P. R. & Beyssac, O. From organic matter to graphite: graphitization. Elements 10, 421–426 (2014).
Choi, S., Lee, S. K., Kim, N. H., Kim, S. & Lee, Y. N. Raman spectroscopy detects amorphous carbon in an enigmatic egg from the Upper Cretaceous Wido Volcanics of South Korea. Front. Earth Sci. 7, 349 (2020).
Chave, K. E. Carbonates: association with organic matter in surface seawater. Science 148, 1723–1724 (1965).
Suess, E. Interaction of organic compounds with calcium carbonate. I. Association phenomena and geochemical implications. Geochim. Cosmochim. Acta 34, 157–168 (1970).
Borromeo, L. et al. Raman spectroscopy as a tool for magnesium estimation in Mg‐calcite. J. Raman Spectrosc. 48, 983–992 (2017).
Wiemann, J., Crawford, J. M. & Briggs, D. E. Phylogenetic and physiological signals in metazoan fossil biomolecules. Sci. Adv. 6, eaba6883 (2020).
Lafuente, B., Downs, R. T., Yang, H. & Stone, N. in Highlights in Mineralogical crystallography (eds Armbruster, T. & Danisi, R. M.) Ch. 1, 1–30 (De Gruyter, 2015).
Mikhailov, K. E. Classification of fossil eggshells of amniotic vertebrates. Acta Palaeontol. Pol. 36, 21–39 (1991).
Wiemann, J. & Briggs, D. E. G. Raman spectroscopy is a powerful tool in molecular paleobiology: an analytical response to Alleon et al. BioEssays 44, 2100070 (2022).
Wiemann, J. et al. Fossilization transforms vertebrate hard tissue proteins into N-heterocyclic polymers. Nat. Commun. 9, 4741 (2018).
Anthony, J. W., Bideaux, R. A., Bladh, K. W. & Nichols, M. C. Handbook of Mineralogy: Volume I. Elements, Sulfides, Sulfosalts (Mineral Data Pub., 1990).
Stein, K. et al. Structure and evolutionary implications of the earliest (Sinemurian, Early Jurassic) dinosaur eggs and eggshells. Sci. Rep. 9, 4424 (2019).
Legendre, L. J. et al. A giant soft-shelled egg from the Late Cretaceous of Antarctica. Nature 583, 411–414 (2020).
Bapst, D. W. paleotree: an R package for paleontological and phylogenetic analyses of evolution. Methods Ecol. Evol. 3, 803–807 (2012).
Revell, L. J. phytools: an R package for phylogenetic comparative biology (and other things). Methods Ecol. Evol. 3, 217–223 (2012).
Paradis, E. & Schliep, K. ape 5.0: an environment for modern phylogenetics and evolutionary analyses in R. Bioinformatics 35, 526–528 (2019).
Harmon, L. J. et al. GEIGER: investigating evolutionary radiations. Bioinformatics 24, 129–131 (2008).
Acknowledgements
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
Contributions
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
Ethics declarations
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.
Rights and permissions
About this article
Cite this article
Norell, M.A., Wiemann, J., Menéndez, I. et al. Reply to: Triassic sauropodomorph eggshell might not be soft. Nature 610, E11–E14 (2022). https://doi.org/10.1038/s41586-022-05152-8
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41586-022-05152-8
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.