Original collagen survived 66 million years inside dinosaur bones, upending a core fossil rule

For decades, a bedrock assumption in paleontology held that fossilization erased the original organic molecules once present in bone, teeth and tissue. Proteins were simply not expected to endure for tens of millions of years. A study led by the University of Liverpool now challenges that view directly, reporting strong evidence that remnants of original collagen can persist inside a dinosaur fossil dating to the end of the age of dinosaurs.

Collagen detected in an Edmontosaurus hip bone

The research centered on an exceptionally well-preserved sacrum from Edmontosaurus, a duck-billed dinosaur. The sacrum is a set of vertebrae fused to the pelvis, forming part of the lower spine, and this specimen weighed a substantial 22 kilograms. Using modern analytical techniques, the team detected molecular signatures associated with collagen, the main structural protein in bone. The work, published in the journal Analytical Chemistry, added new weight to a debate that has run for roughly three decades over whether ancient proteins can genuinely survive inside fossils, as described in a summary of the findings.

A fossil from the Hell Creek Formation

The bone was excavated from Upper Cretaceous rock layers in the Hell Creek Formation of South Dakota, a geological unit famous for preserving fossils from near the close of the Cretaceous period. That setting places the specimen at roughly 66 million years old, close to the mass extinction that ended non-avian dinosaurs. Now held in the University of Liverpool’s collections, the fossil’s unusually good preservation is what made it a candidate for molecular analysis. Preservation quality matters enormously in this kind of work, because degraded or contaminated material can obscure whether any organic trace is truly original to the animal.

Mass spectrometry and a telltale amino acid

The team leaned on several forms of advanced analysis, including protein sequencing and mass spectrometry, a method that identifies molecules by measuring their mass and chemical properties. Researchers from UCLA used tandem mass spectrometry to detect and quantify hydroxyproline, an amino acid strongly associated with collagen when it is found in bone. The Centre for Proteome Research at the University of Liverpool identified fragments of collagen alpha-1, the primary form of collagen in bone tissue. Together these lines of evidence pointed to degraded collagen genuinely embedded in the fossil rather than a modern substance sitting on its surface. The peer-reviewed report documenting the chemical evidence appeared in Analytical Chemistry.

Answering the contamination objection

The contamination question has long been the central sticking point in this field. Skeptics have argued that any organic material found in fossils could have arrived much later from microbes, soil, handling or other environmental sources, rather than being a survivor from the living animal. The Liverpool-led results are framed as a direct rebuttal to that objection, with the team stating that the findings refute the idea that all organics in fossils must be contamination. By combining multiple independent techniques and specifically targeting molecules tied to bone collagen, the researchers built a case that at least some of the detected material is authentically associated with the original fossilized bone.

A century of old images worth a second look

One of the more striking implications concerns a technique that has been in use for about a hundred years. Cross-polarized light microscopy relies on specially filtered light to reveal structures that ordinary microscopy can miss, and scientists have collected such images of fossil bone for roughly a century. The study suggests those archives should be revisited, because they may already show intact patches of bone collagen. If characteristic patterns can be recognized in that back catalog, researchers could effectively have a ready-made list of promising fossils to examine with newer protein-analysis tools, without needing to dig up anything new. Broader coverage of related fossil research is tracked through science reporting on dinosaurs.

The lingering puzzle of protein survival

Even as it strengthens the case for endogenous proteins, the work leaves a large question open. Proteins are generally expected to break down over long timescales, so how collagen or its fragments could persist inside a fossil for tens of millions of years remains unexplained. Understanding the chemistry and conditions that allow such survival is now a target for further study. If those preservation mechanisms can be pinned down, molecular analysis could offer a new avenue for studying extinct animals, potentially revealing relationships between dinosaur species that skeletal anatomy alone cannot resolve. It is worth noting that the underlying chemical results were first published in the scientific literature before the wider attention they later drew, so the finding represents a maturing line of evidence rather than a single overnight revelation.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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