This is a very interesting work providing rare chemical data on extinct organisms. To my knowledge it is the first report on the pigments of dinosaur eggs. However, it should be mentioned that biliverdin and protoporphyrin have previously been detected in subfossil eggshells from extinct birds and I suggest to cite the following paper:
Igic, B., Greenwood, D., Palmer, D., Cassey, P., Gill, B., Grim, T., Brennan, P.R., Bassett, S., Battley, P., Hauber, M., 2010. Detecting pigments from colourful eggshells of extinct birds. Chemoecology 20, 43-48.
It is interesting that the fossil pigments are preserved in a carbonate biomineral matrix that protected these compounds from degradation over millions of years. Similar observations have been made in the case of fossil pigments from crinoids and putative red algae:
Wolkenstein, K., 2015. Persistent and widespread occurrence of bioactive quinone pigments during post-Paleozoic crinoid diversification. Proc. Natl. Acad. Sci. USA 112, 2794-2799.
Wolkenstein, K., Gross, J.H., Falk, H., 2010. Boron-containing organic pigments from a Jurassic red alga. Proc. Natl. Acad. Sci. USA 107, 19374-19378.
I’m looking forward to seeing the final article.
Dr. Klaus Wolkenstein, Geoscience Centre, University of Göttingen, firstname.lastname@example.org