Evidence for Endogenous Collagen in Edmontosaurus Fossil Bone

Reports of proteins in fossilized bones have been a subject of controversy in the scientific literature because it is assumed that fossilization results in the destruction of all organic components. In this paper, a novel combination of analytical techniques is used to address this question for an exceptionally well-preserved Edmontosaurus sacrum excavated from the Upper Cretaceous strata of the South Dakota Hell Creek Formation. Cross-polarized light microscopy (XPol) shows birefringence consistent with collagen presence. Tandem LC-MS unambiguously identified, and for the first time quantified, hydroxyproline, a unique collagen-indicator amino acid, in acid-digested samples from the Edmontosaurus. LC-MS/MS bottom-up proteomics shows identical collagen peptide sequences previously identified and reported for another hadrosaur and a T. rex sample.