Microscope view of a pterosaur fossil section showing carbon coating and mineral layers. Credit: Grice et al., iScience (2026).
A perfectly preserved prehistoric pterosaur wing found in northeastern Brazil, has written the fossil rulebook regarding the flying reptile.
An international study led by Curtin University has revealed new insights into how an ancient flying reptile was preserved in extraordinary detail for 113 million years – offering a rare glimpse into a vanished world.
That the fossilised wing phalanx of a prehistoric pterosaur, found in northeastern Brazil, was so remarkably preserved in three dimensions, even retaining chemical traces hinting at its diet, is thanks to the action of special bacteria and a unique ancient marine environment.
Lead author Professor Kliti Grice, a John Curtin Distinguished Professor and founding Director of the Western Australian Organic and Isotope Geochemistry Centre at Curtin, said the findings open a new window into fossil formation: “This fossil is a true time capsule; not only is it beautifully preserved, but for the first time we’ve detected traces of steroids in a pterosaur, providing further evidence that these creatures likely fed on fish or squid.
“It also marks the first time molecules have been recovered from a pterosaur fossil, revealing new clues about its diet and highlighting the growing potential of molecular palaeontology to unlock secrets from deep time.
“Steroid preservation in fossils is exceptionally rare but what’s even more fascinating is that our findings challenge long-held ideas about fossil preservation itself.
“Rather than being destroyed by oxygen, some fossils are preserved because of it, through oxidative processes carried out by ancient microbiomes.”
Perfect storm
Grice added: “After this pterosaur died and sank to the seabed, a perfect storm of chemistry, biology and the environment worked to seal its story in stone.
“Microbes, including sulfur-oxidising bacteria, began breaking down the soft tissue and fats and triggered mineralisation around the body – a process that, over time, helped preserve its structure in incredible detail for more than 100 million years.”
Pterosaurs were flying reptiles that lived alongside dinosaurs and were the first vertebrates to master powered flight, with some species reaching wingspans of up to 12 metres.
Like modern birds, they had hollow bones, which in certain environmental conditions increased the changes of exceptional fossil preservation.
Grice said the team’s research reveals a new pathway for remarkable fossil preservation, offering fresh insights into ancient life and the unique environmental conditions that enable such remarkable fossilisation.
She said: “It adds to the growing evidence that tiny microbes played a big role in this process, something we are now identifying at other fossil sites, presenting a new global Lagerstätten mechanism – the special conditions that make exceptional preservation possible.”
The research is published in iScience.
