Scientists Find Dinosaur Blood Cells in 115-Million-Year-Old Fossil

Scientists have discovered fossilized red blood cells and traces of heme in the bones of a 115-million-year-old dinosaur, marking a first-of-its-kind find that could reshape understanding of molecular preservation. The cells were found in the hind leg bones of an Aratasaurus from northeastern Brazil, examined via electron microscope and chemical tests. Lead author Kliti Grice called it a "mineral and molecular echo" of original biology, though not actual dinosaur blood. Researchers emphasize the goal is studying deep-time molecular preservation, not recreating dinosaurs, and the findings face skepticism from biologist Mary Schweitzer, who questions whether the structures are truly red blood cells.