Isophoric News · Tuesday, November 3, 2026
Study reports possible red blood cells and heme in a 115-million-year-old dinosaur bone; an outside expert is not convinced
Researchers led by Kliti Grice of Curtin University in Western Australia reported microscopic structures resembling red blood cells, along with chemical signatures of heme, in the limb bones of Aratasaurus museunacionali, a small meat-eating dinosaur that lived in what is now Brazil about 115 million years ago, according to Live Science and the Guardian. The study, "Heme signatures in mineralized red blood cells within vascular canals of a 115-million-year-old dinosaur bone," was published 2 November in the Proceedings of the National Academy of Sciences, Live Science reported. The team also found amino acids associated with collagen, both outlets reported. Mary Schweitzer, a molecular paleontologist at North Carolina State University who was not involved, told Live Science she was "not convinced" the images show red blood cells. She said nonmammalian red cells keep their nuclei and should show a nuclear bulge, while the structures were concave and smaller than most such cells. The Guardian reported she was more persuaded by the heme and collagen findings. Grice told the Guardian the work does not imply that large molecules such as proteins or DNA survive in fossils. She said a manganese oxide mineral, hausmannite, may have stabilized the structures before fossilization.
