Resonance Raman confirms partial haemoglobin preservation in dinosaur remains

Still soft, hollow, flexible structures morphologically consistent with blood vessels, vascular contents, cells (osteocytes) and collagenous matrix were recovered from demineralized bone of a number of Mesozoic vertebrate remains, but the origin of these materials is hotly debated, in part because it refutes taphonomic models of degradation. Here, we apply the double selectivity of resonance Raman (RR) to show the presence of haeme that is still bound to a protein moiety in these tissues. Evidence of haeme degradation is found. Additional data support a diagenetic pathway, showing that haeme is also bound to the mineral goethite. This suggests the dual role that iron may play in facilitating the cross-linking of organic residues and stabilizing those residues by association with an iron mineral.