Kliti Grice, Stephen F. Poropat, Lorenz Schwark, Maria A. Diaz Mateus, Paul F. Greenwood, Luke Brosnan, Madison Tripp, Amy L. Elson, Andrew J.Y. Jian, Antônio Á. F. Saraiva, Renan A. M. Bantim, Julien Demore, Alex I. Holman, Michael E. Böttcher, Adele H. Pentland, Robert H.C. Madden, Peter Hopper, Xiao Sun, Aaron Dodd, Arthur V. de Oliveira, Pieter T. Visscher, William D.A. Rickard, Juliana M. Sayão, Hossein Rahimpour-Bonab, Iris Schmiedinger, Victor O. Leshyk, ALEXANDER W.A. KELLNER
The combined preservation of soft tissues, biomineralized structures, and molecular biomarkers is rare; yet, such finds offer key insights into ancient physiology, ecology, and taphonomy. We integrate organic geochemical analyses with high-resolution micro-mineral imaging of a three-dimensionally preserved Cretaceous pterosaur wing phalanx from Brazil to reveal steroid biomarkers and multi-stage mineralization pathways underlying its preservation. A localized redox shift toward acidic, oxidative conditions around the carcass played a central role. Microbial decay generated acidity that promoted early phosphate mineralization (fluorapatite), stabilizing tissues. This fluorapatite is associated with barite and celestite indicating a microenvironment with enhanced microbial sulfate production. Following phosphatization, three phases of carbonate mineralization encapsulated organic compounds, protecting them from diagenetic alteration. Molecular analyses report steroids in pterosaurs, with δ 13 C values indicating a fish- and cephalopod-based diet, highlighting early mineralization as key to long-term biomolecule preservation.