For decades, scientists believed that dinosaur fossils were nothing more than mineralized rocks, and that the original biological material had long been destroyed over time. But an extraordinary study centered on the remarkably preserved Edmontosaurus fossil casts serious doubt on that assumption.
Researchers led by the University of Liverpool have found strong evidence that traces of the original organic molecules, including collagen, are still present in dinosaur bones from around 66 million years ago. The discovery adds powerful new support to a controversial idea that has divided paleontologists for more than 30 years.
Preserved collagen found in dinosaur bones
The fossil at the center of the study is a 22-kilogram Edmontosaurus sacrum, part of a dinosaur’s hip, recovered from South Dakota’s famous Hell Creek Formation. Edmontosaurus was a large duck-billed herbivore that lived alongside Tyrannosaurus rex near the end of the Cretaceous period.
Scientists used a combination of advanced experimental techniques, including protein sequencing and several forms of mass spectrometry, to detect remnants of collagen embedded within fossilized bones. Collagen is the major structural protein found in bone tissue and is one of the most difficult biomolecules to account for as contamination when identified in this context.
UCLA researchers also identified hydroxyproline, an amino acid that is strongly associated with bone collagen. According to the research team, this provided important evidence that fragments of degraded collagen were indeed present inside the fossil.
Professor Steve Taylor, Chair of the Mass Spectrometry Research Group in the School of Electrical Engineering and Electronics at the University of Liverpool, said:
“This study shows beyond doubt that organic biomolecules, such as collagen-like proteins, are likely present in some fossils.”
“Our results have far-reaching implications. First, they refute the hypothesis that organic matter in fossils must have resulted from pollution.”
The debate that divided paleontology
The claim that dinosaur fossils preserve soft tissues and proteins has sparked intense debate since the early 2000s. Some scientists argued that the reported substances were not real dinosaur molecules, but modern pollution or bacterial residue.
One of the most famous discoveries occurred in 2005, when paleontologist Mary Schweitzer and colleagues reported the soft tissue structure inside a Tyrannosaurus rex fossil. Subsequent studies identified collagen and possible blood vessel-like structures in additional dinosaur specimens, including hadrosaurids related to Edmontosaurus.
The new Edmontosaurus analysis stands out because the researchers used multiple independent testing methods to examine the same fossil. Using a combination of microscopy, chemical analysis and protein sequencing, the researchers aimed to rule out contamination and strengthen their case that the molecules came from the dinosaurs themselves.
The survey results are analytical chemistry It was published in 2025 under the title “Evidence for endogenous collagen in the fossil bones of Edmontosaurus.”
Why is this discovery important?
If proteins can survive for tens of millions of years in fossils, scientists may have a whole new way to study extinct animals.
Tiny molecular signatures could reveal evolutionary relationships between dinosaur species that are difficult to determine from bones alone. Researchers will also be able to learn more about dinosaur growth, aging, physiology, and disease.
Taylor noted that scientists may need to reexamine fossil samples collected over the past century. Cross-polarized microscopy images taken decades ago may contain overlooked evidence of collagen preserved in ancient bones.
“These images may reveal intact sections of bone collagen, potentially providing a trove of ready-made fossil candidates for further protein analysis,” Taylor explained.
“This could provide new insights into dinosaurs, including revealing connections between previously unknown dinosaur species.”
The mystery of molecular survival
The discovery also raises interesting scientific questions about how these molecules have survived so long.
Proteins typically degrade over time, especially over geological time scales. However, some fossils appear to be able to preserve minute biological structures under certain conditions.
Scientists are investigating whether mineral interactions inside bones help protect collagen fragments from complete breakdown. Recent studies examining fossil biomolecules suggest that specific burial environments and microscopic bone structures can create stable conditions that dramatically slow chemical decomposition.
Edmontosaurus fossils are already famous for their excellent preservation. Some specimens discovered over the past century have left behind detailed skin marks and other soft tissue features, earning them the nickname “dinosaur mummies.”
Recent paleontological studies continue to reveal surprisingly detailed soft tissue preservation in Edmontosaurus specimens, including evidence of fleshy structures and preserved skin anatomy.
These discoveries are changing the way scientists think about fossils. Researchers are beginning to see some fossils as possible molecular time capsules, preserving traces of prehistoric biology millions of years later.
