For decades, scientists believed dinosaur fossils were little more than mineralized rock, with any original biological material long since destroyed by time. But an extraordinary study centered on a remarkably preserved Edmontosaurus fossil is challenging that assumption in a major way.
Researchers led by the University of Liverpool uncovered strong evidence that traces of original organic molecules, including collagen, still exist inside dinosaur bones dating back roughly 66 million years. The discovery adds powerful new support to a controversial idea that has divided paleontologists for more than 30 years.
Preserved Collagen Found in Dinosaur Bone
The fossil at the center of the study is a 22-kilogram Edmontosaurus sacrum, part of the dinosaur’s hip region, recovered from South Dakota’s famous Hell Creek Formation. Edmontosaurus was a large duck-billed plant eater that lived alongside Tyrannosaurus rex near the end of the Cretaceous Period.
Using a combination of advanced laboratory methods, including protein sequencing and several forms of mass spectrometry, scientists detected remnants of collagen embedded within the fossilized bone. Collagen is the primary structural protein found in bone tissue and one of the hardest biomolecules to explain away as contamination when identified in this context.
Researchers from UCLA also identified hydroxyproline, an amino acid strongly associated with collagen in bone. According to the team, this represented an important confirmation that degraded collagen fragments were genuinely present inside the fossil.
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.”
A Debate That Has Divided Paleontology
Claims of preserved soft tissues and proteins in dinosaur fossils have sparked fierce debate since the early 2000s. Some scientists argued the reported materials were modern contamination or bacterial residue rather than authentic dinosaur molecules.
One of the most famous discoveries came in 2005, when paleontologist Mary Schweitzer and colleagues reported soft tissue structures inside a Tyrannosaurus rex fossil. Later studies identified possible collagen and blood vessel-like structures in additional dinosaur specimens, including hadrosaurs related to Edmontosaurus.
The new Edmontosaurus analysis stands out because researchers used multiple independent testing methods to examine the same fossil. By combining microscopy, chemical analysis, and protein sequencing, the team aimed to rule out contamination and strengthen the case that the molecules were original to the dinosaur itself.
The findings were published in Analytical Chemistry in 2025 under the title “Evidence for Endogenous Collagen in Edmontosaurus Fossil Bone.”
Why This Discovery Matters
If proteins can survive in fossils for tens of millions of years, scientists may gain an entirely new way to study extinct animals.
Tiny molecular traces could potentially reveal evolutionary relationships between dinosaur species that are difficult to identify from bones alone. Researchers may also learn more about dinosaur growth, aging, physiology, and disease.
Taylor noted that scientists may now need to revisit fossil samples collected over the past century. Cross-polarized light microscopy images taken decades ago could contain overlooked evidence of preserved collagen in ancient bones.
“These images may reveal intact patches of bone collagen, potentially offering a ready-made trove of fossil candidates for further protein analysis,” Taylor explained.
“This could unlock new insights into dinosaurs, for example revealing connections between dinosaur species that remain unknown.”
The Mystery of Molecular Survival
The discovery also raises a fascinating scientific question: how did these molecules survive for so long?
Proteins normally break down over time, especially across geological timescales. Yet some fossils appear capable of preserving microscopic biological structures under specific conditions.
Scientists are increasingly investigating whether mineral interactions inside bone may help shield fragments of collagen from complete decay. Recent studies exploring fossil biomolecules suggest that certain burial environments and microscopic bone structures may create stable conditions that slow chemical breakdown dramatically.
Edmontosaurus fossils are already famous for their exceptional preservation. Some specimens discovered over the last century retained detailed skin impressions and other soft tissue features, earning the nickname “dinosaur mummies.”
More recent paleontology research has continued uncovering surprisingly detailed soft tissue preservation in Edmontosaurus specimens, including evidence of fleshy structures and preserved skin anatomy.
Together, these discoveries are reshaping how scientists think about fossils. Instead of viewing them solely as stone replicas of ancient bones, researchers are beginning to see some fossils as possible molecular time capsules that still preserve traces of prehistoric biology millions of years later.