A remarkable 113-million-year-old pterosaur fossil from northeastern Brazil has provided rare evidence of soft tissue, organic molecules, and chemical markers indicating a diet rich in cephalopods, including fish and squid.
Grice et al. integrate organic geochemical analysis and high-resolution micromineral imaging of a Cretaceous pterosaur bone in Brazil, revealing steroid biomarkers and the intricate petrification pathways that facilitated its preservation. Image credit: Grice et al., doi: 10.1016/j.isci.2026.116199.
“Our discovery paves the way for new understanding in fossil formation,” stated Professor Kriti Grice from Curtin University, lead author of the study.
In this groundbreaking research, Professor Grice and his team analyzed the left wing of an Early Cretaceous pterosaur found in the Sitio Baixa Grande locality of Brazil’s Araripe Basin.
This site, part of the Romuald Formation, is celebrated for its exceptional preservation of vertebrate fossils, particularly pterosaur species.
The wings of this pterosaur were encased in limestone concretions, preserving intricate details.
Paleontologists uncovered microstructures, including preserved collagen-like fibers, calcified soft tissue, and steroid biomarkers.
Carbon isotope analysis of cholesterol-derived compounds suggests that this pterosaur functioned as an aerial predator, likely hunting cephalopods and fish above the seas during the Cretaceous period, occupying a higher trophic level in the food web.
“This fossil serves as a time capsule. It’s not only beautifully preserved but also marks the first time we’ve detected steroid traces in a pterosaur, offering further evidence of their dietary preferences for fish and squid,” Professor Grice remarked.
“This is also the first instance of molecule recovery from a pterosaur fossil, unlocking new insights into their diet and showcasing the emerging potential of molecular paleontology,” he added.
“The preservation of steroids in fossils is incredibly rare, but our findings challenge conventional beliefs about fossil preservation,” he emphasized.
The researchers employed chemical, isotopic, and high-resolution imaging techniques to reconstruct the fossilization process.
They concluded that the decomposing carcass generated a unique chemical environment.
The acidity resulting from microbial activity led to the formation of phosphate minerals that stabilized the tissue, while subsequent carbonate lithification waves protected the site and prevented further decomposition of organic materials.
This study challenges the long-held idea that only oxygen-poor conditions facilitate exceptional fossil preservation.
Instead, the researchers propose that local oxidized and reduced conditions around the decomposing animal played a crucial role in fossil conservation.
“Our research opens new pathways for fossil preservation, shedding light on ancient life and the unique environmental conditions that enabled such remarkable fossilization,” added Professor Grice.
“This further supports the notion that microorganisms significantly contribute to this process, a finding confirmed at other fossil sites, proposing a new global Lagerstätten mechanism for extraordinary fossil preservation.”
The team’s findings are published in this week’s issue of iscience.
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Kriti 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
