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.
Grice et al. (Mon,) studied this question.