Dinosaur Fossil Yields Possible Red Blood Cell Traces

Researchers report finding microscopic structures resembling red blood cells, along with heme-related chemical traces, in a roughly 115-million-year-old dinosaur fossil from Brazil. The study, published in the Proceedings of the National Academy of Sciences, examines limb bone from Aratasaurus museunacionali, but an outside expert disputes whether the structures are blood cells. The researchers identified oval structures in vascular canals, channels that once carried blood vessels through the bone. They used microscopic imaging and chemical analyses to examine the forms and their surroundings. The study authors say heme-related signals were detected in the structures themselves, strengthening their interpretation that the forms are mineralized remnants of red blood cells. Heme is a molecule associated with hemoglobin, the protein that transports oxygen in blood. The findings concern heme-related molecules and cell-like shapes, not intact blood or preserved hemoglobin protein. Lead author Kliti Grice has emphasized that the discovery is a mineral and molecular trace of ancient biology, not a vial of dinosaur blood. Mary Schweitzer, a paleontologist who was not involved in the...