Red-blood-cell-like structures found in 115-million-year-old dinosaur bone

Researchers studying a roughly 115-million-year-old Aratasaurus leg bone from Brazil report structures resembling red blood cells and heme-related chemical traces. The structures sit inside the bone’s vascular canals, where the team says surrounding sediment left no comparable traces. The proposed blood-cell remains were mineralized, not preserved as fresh blood, and the research did not document dinosaur DNA. Earlier dinosaur fossils have also produced reported blood-cell finds.