Traces of red blood cells found in a dinosaur bone
· BehindLines newsroom
An international team led by Curtin University in Australia reports detecting mineralized blood cells and molecules derived from hemoglobin in a dinosaur bone about 115 million years old. The study, published in early November in the journal PNAS, presents what would be the first chemical confirmation of this kind for fossil red blood cells, according to Curtin.
A small theropod from Brazil
According to Sci.News, the hind-limb bones belong to Aratasaurus museunacionali, an Early Cretaceous theropod found in northeastern Brazil, at the Mina Pedra Branca site in the Romualdo Formation. Popular Science describes a juvenile individual, unearthed in 2008, whose length is estimated at more than ten feet, or more than three meters.
The researchers observed numerous small ellipsoidal structures inside the bone's vascular canals. Sci.News reports that they average about 23 micrometers long and 20 wide.
What the analyses show
Also according to Sci.News, the team identified heme B, the molecule at the heart of oxygen transport by hemoglobin, as well as a chemically modified form. Imaging and spectroscopy revealed other heme signatures in the same structures. Curtin adds that amino acids associated with collagen were also found.
To explain this preservation, the authors point to a manganese-based mineral, hausmannite, which would have stabilized the cells. They also suppose rapid burial in an oxygen-poor, microbe-rich environment, according to Curtin's press release.
What it changes, and the limits
The study's lead, Professor Kliti Grice, calls the discovery "major" and says it challenges the idea that hemoglobin cannot survive over geological timescales. According to Curtin, the results could help study the evolution of blood, metabolism and activity levels in extinct animals. Her colleague Martin Van Kranendonk also mentions possible implications for astrobiology, the search for traces of ancient life elsewhere in the Universe.
The articles covering the study nevertheless urge caution. Sci.News specifies that the results do not mean intact blood or whole hemoglobin proteins survived: these are molecular traces preserved in mineralized remains of cells. Popular Science presents the implications for metabolism, blood evolution and astrobiology as avenues for future study, not as established results.
The study, titled "Heme signatures in mineralized red blood cells within vascular canals of a 115-million-year-old dinosaur bone", appeared in PNAS, volume 123, issue 46.