Red blood cell traces found in 115-million-year-old dinosaur fossil

Scientists have found chemical evidence of red blood cells in a 115 million-year-old dinosaur bone, marking the strongest evidence yet of such biological material in a fossil and offering new clues about how it can survive. The study, published Monday in Proceedings of the National Academy of Sciences, detected microscopic structures resembling red blood cells and heme, a molecule in hemoglobin, within the bone of Aratasaurus museunacionali from Brazil. Researchers used advanced imaging and chemical analyses, suggesting low-oxygen burial conditions helped preserve the cells. Experts remain divided on whether the structures are truly red blood cells, with some questioning their shape and chemical markers. The findings could open new research avenues into prehistoric physiology, though they do not bring scientists closer to recreating dinosaur DNA.