A remarkable 113-million-year-old pterosaur fossil discovered in northeastern Brazil has provided rare evidence of preserved soft tissue, organic molecules, and chemical signatures indicative of a diet rich in cephalopods such as fish, squid, and relatives of nautiluses.
Grice et al. conducted an organic geochemical analysis and high-resolution micromineral imaging of a three-dimensionally preserved Cretaceous pterosaur bone in Brazil, revealing steroid biomarkers and complex petrification pathways involved in its remarkable preservation. Image credit: Grice et al., doi: 10.1016/j.isci.2026.116199.
“Our groundbreaking discovery sheds new light on fossil formation,” asserted Professor Kriti Grice from Curtin University, the lead author of the study.
The research team examined the left wing section of an Early Cretaceous pterosaur from the Sitio Baixa Grande locality in northwestern Brazil’s renowned Araripe Basin, famous for its exceptional vertebrate fossil preservation.
This particular fossil was encased in limestone concretions, showcasing remarkable details.
Paleontologists observed microstructures within the specimens, revealing preserved collagen-like fibers, calcified soft tissue, and crucial steroid biomarkers.
Carbon isotope analysis of cholesterol-derived compounds indicated that this pterosaur was an aerial predator, hunting above the sea during the Cretaceous period.
It is believed to have fed on fish and cephalopods, occupying a significant position in the Cretaceous food web.
“This fossil acts as a time capsule. Its exquisite preservation and the detection of steroid traces in a pterosaur provide compelling evidence that these ancient creatures likely consumed fish and squid,” stated Professor Grice.
This study marks the first recovery of molecules from a pterosaur fossil, offering fresh insights into their diet and highlighting the potential of molecular paleontology to reveal secrets of our planet’s prehistoric past.
“The preservation of steroids in fossils is extremely rare, yet our findings challenge long-standing beliefs about fossil preservation methods,” he added.
The researchers employed chemical, isotopic, and high-resolution imaging techniques to reconstruct the fossilization process.
They found that the carcass generated a localized chemical environment during decomposition.
The acidity from microbial activity facilitated the formation of phosphate minerals that stabilized the tissue, while subsequent carbonate lithification waves sealed the site, preserving organic compounds from further decomposition.
This study challenges the long-held assumption that only oxygen-deprived conditions are essential for exceptional fossil preservation.
Instead, the researchers argue that fluctuations between oxidized and reduced conditions surrounding the decomposing animal played a crucial role in preserving the fossil.
“Our findings illuminate new pathways for incredible fossil preservation and offer deeper insights into ancient life and the unique environmental conditions that enabled such remarkable fossilization,” reflected Professor Grice.
“This adds to the evidence showing that tiny microorganisms significantly contribute to this process, which we’ve recognized at various fossil sites, suggesting the existence of a new global Lagerstätten mechanism that fosters extraordinary preservation.”
For a detailed understanding of the team’s findings, published in this week’s issue of iScience, please refer to the original publication.
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Grice et al. Multistep mineralization and biomarker preservation in 113 million-year-old pterosaur bones through redox shifts in diagenesis. iScience, published online June 18, 2026. doi: 10.1016/j.isci.2026.116199
Source: www.sci.news