Fossils are our best ally to better understand the way of life of ancient and extinct creatures. These remains of living organisms, now fossilized, can provide a number of valuable indications, from diet to the color of the animal discovered. But the fossilization process is delicate and the internal soft tissues degrade before they can be discovered.
For the first time, however, scientists have detected traces of ancient steroids on a pterosaur wing, dating back 113 million years. The fossil was remarkably well preserved – probably thanks to tiny microorganisms, reports IFL Science.
The Romualdo Formation, a geological layer located in Brazil, is renowned for the number of fossilized pterosaurs that have been discovered there. These flying reptiles could measure 8 to 9 meters long. The fossils are trapped in calcium carbonate, which allows extraordinary details to be preserved: organs, tissues and fine bone structures.
Steroid discovery
“This fossil is a true time capsule: not only is it beautifully preserved, but it is also the first time we have detected traces of steroids in a pterosaur, confirming that these creatures probably fed on fish or squid”comments Professor Kliti Grice, from Curtin University, Australia.
Steroids are organic molecules present in all living organisms and their composition varies slightly depending on the species that produce them and what they consume. These chemical traces can survive for millions of years, long after all visible traces of flesh have disappeared. By analyzing them, the researchers were able to trace their origin: fats and tissues from fish and squid, ingested by the pterosaur.
Like modern-day birds, the wing bones of pterosaurs were hollow, which allowed minerals to form within the bones themselves. The fossil was probably found in water rich in hydrogen sulfide and poor in oxygen. “After the death of this pterosaur, which sank to the seabed, a perfect conjunction of chemical, biological and environmental factors sealed its story in stone”explains Kliti Grice.
“Microorganisms, including sulfo-oxidizing bacteria, began to break down soft tissue and fat, triggering mineralization around the body. This process made it possible to preserve its structure down to the smallest detail for more than 100 million years.”
