How a 22-Kilogram Edmontosaurus Sacrum Rewrites Fossilization Science

For decades, the prevailing view in paleontology held that fossilization destroyed the original biological molecules inside bones and teeth. Proteins such as collagen were not expected to survive for tens of millions of years. That assumption has now been directly challenged by a University of Liverpool-led study published in Analytical Chemistry.

The team examined the sacrum — part of the lower spine connected to the pelvis — of an Edmontosaurus, a duck-billed dinosaur. The 22-kilogram specimen was excavated from Upper Cretaceous rocks in South Dakota's Hell Creek Formation, a site that preserves life from near the end of the dinosaur era. Because the fossil was exceptionally well preserved, researchers could apply protein sequencing and mass spectrometry to look for molecular traces of bone collagen.

The key finding is the detection of collagen-specific signatures, including the amino acid hydroxyproline, which researchers from UCLA quantified for the first time in such a fossil using tandem mass spectrometry. University of Liverpool scientists also identified fragments of collagen alpha-1, the main form of collagen found in bone tissue. Professor Steve Taylor, chair of the university's Mass Spectrometry Research Group, said the results show "beyond doubt" that organic biomolecules appear to be present in some fossils.

Why the Liverpool and UCLA Collagen Data Matter for Dinosaur Research

What the Liverpool Results Do to the Contamination Argument

The central dispute over fossil proteins has been whether detected organics are original or introduced later by microbes, soil, or human handling. The study strengthens the case that at least some collagen in this specimen is genuinely associated with the original bone, rather than contamination. That does not mean every past organic find is valid, but it refutes the blanket hypothesis that all organics in fossils must result from contamination.

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A Century of Fossil Images May Contain Hidden Candidates

Professor Taylor notes that cross-polarized light microscopy images of fossil bones have been collected for roughly a century. If intact patches of bone collagen can be recognised in those archived images, existing museum and university collections may already hold a large trove of fossils worth re-examining with modern protein analysis. That would lower the need for destructive sampling and widen the pool of specimens suitable for molecular study.

The Bigger Mystery Is Why the Protein Survived

The finding raises a question the paper does not fully answer: how collagen or its fragments could persist inside a fossil for tens of millions of years when proteins normally break down over much shorter timescales. Solving that mechanism could inform both paleontology and materials science, but for now the survival process remains unexplained.

What Fossil Collections and Researchers Can Do Next

The discovery points to concrete next steps for fossil collections and research teams.

  • Museums and universities holding Upper Cretaceous fossils can re-examine existing cross-polarized light microscopy images for intact collagen patches before deciding which specimens to sample.
  • Researchers can use hydroxyproline detection via tandem mass spectrometry as a specific marker for collagen when screening fossil bone, following the UCLA method used on the Edmontosaurus sacrum.
  • Field teams working in fossil-rich units such as the Hell Creek Formation may prioritise exceptionally preserved, articulated bone for molecular analysis, since preservation quality appears central to protein survival.