For decades, scientists generally assumed that fossilization destroyed the original organic molecules once present in bones, teeth, and other tissues. Under that view, proteins and other biological materials were not expected to survive for tens of millions of years.
New research led by the University of Liverpool now provides strong evidence that some Mesozoic fossils, including dinosaur bones and teeth, can retain traces of those original organic materials.
Using advanced analytical methods, researchers detected remnants of collagen in the hip bone of an Edmontosaurus, a duck billed dinosaur. The finding adds important new evidence to a scientific debate that has continued for about 30 years.
Ancient Collagen Found in a Dinosaur Fossil
The study, published in Analytical Chemistry, examined an exceptionally well preserved Edmontosaurus sacrum weighing 22 kilograms. The sacrum is a group of vertebrae connected to the pelvis and forms part of the animal’s lower spine.
The fossil was excavated from Upper Cretaceous rock layers in the Hell Creek Formation of South Dakota. This famous geological formation preserves fossils from near the end of the age of dinosaurs. The specimen is now part of the University of Liverpool’s collections.
Because of its unusually good preservation, the fossil gave researchers an opportunity to apply several modern techniques, including protein sequencing and mass spectrometry.
Mass spectrometry is a method that helps scientists identify molecules by measuring their mass and chemical properties. In this case, it allowed the team to search for molecular signatures associated with collagen, the major structural protein found in bone.
Evidence That Fossil Proteins Can Survive
Professor Steve Taylor, chair of the Mass Spectrometry Research Group at the University of Liverpool’s Department of Electrical Engineering & Electronics, said:
“This research shows beyond doubt that organic biomolecules, such as proteins like collagen, appear to be present in some fossils.
“Our results have far-reaching implications. Firstly, it refutes the hypothesis that any organics found in fossils must result from contamination.
“Secondly, it suggests that cross-polarized light microscopy images of fossil bones, collected for a century, should be revisited. These images may reveal intact patches of bone collagen, potentially offering a ready-made trove of fossil candidates for further protein analysis. This could unlock new insights into dinosaurs — for example revealing connections between dinosaur species that remain unknown.
“Lastly, the findings inform the intriguing mystery of how these proteins have managed to persist in fossils for so long.”
The contamination question has been one of the central issues in the debate over ancient fossil proteins. Critics have argued that organic material detected in fossils could have entered the specimens much later from microbes, soil, handling, or other environmental sources. The new results strengthen the case that at least some of the material is genuinely associated with the original fossilized bone.
Old Fossil Images Could Hold New Clues
The findings may also give researchers a new way to identify promising fossils for molecular analysis.
Cross polarized light microscopy uses specially filtered light to reveal structures that may be difficult to see with ordinary microscopy. Scientists have collected such images of fossil bone for roughly a century. If characteristic patches of preserved collagen can be recognized in those older images, researchers may already have a large archive of fossils worth examining with newer protein analysis techniques.
That could help scientists investigate questions that traditional fossil anatomy cannot always answer, including possible biological relationships among dinosaur species.
The discovery also raises a larger mystery. Proteins are generally expected to break down over very long periods of time, so researchers still need to understand how collagen or fragments of it could persist inside fossils for tens of millions of years.
Multiple Techniques Confirmed the Finding
The project brought together specialists from several institutions and research areas.
Researchers from UCLA contributed to the study, using tandem mass spectrometry to detect and quantify — for the first time — the amino acid hydroxyproline, which is specific to collagen when found in bone, thus confirming the presence of decayed collagen.
Hydroxyproline is an amino acid strongly associated with collagen. Detecting it in fossil bone therefore provides an additional chemical clue that degraded collagen is present.
Researchers from the University of Liverpool’s Mass Spectrometry Research Group conducted protein sequencing and mass spectrometry tests.
Specialists from the University’s Materials Innovation Factory carried out additional analyses to confirm the results.
The Centre for Proteome Research at the University of Liverpool identified fragments of collagen alpha-1, the main form of collagen in bone tissue.
Together, the evidence appears to resolve a long running dispute over whether original biological molecules can remain in extremely old fossils. It also opens new possibilities for studying extinct animals at the molecular level, potentially giving scientists access to biological information that was once assumed to have vanished during fossilization.