A team led by researchers at Curtin University in Australia says it has found the strongest chemical evidence yet of preserved blood inside a dinosaur bone — a 115-million-year-old theropod unearthed in northeastern Brazil — though the claim is already drawing skepticism from paleontologists who were not involved in the work.
The fossil belongs to Aratasaurus museunacionali, a meat-eating dinosaur. Examining its limb bones, the team found numerous mineralized structures inside vascular canals — the narrow channels that once carried blood vessels through living bone — that chemical analysis identified as red blood cells containing intact heme, the oxygen-carrying component of hemoglobin. The findings were published in a paper in the Proceedings of the National Academy of Sciences.
"To detect intact heme-derived molecules" after 115 million years is "astonishing," said lead author Kliti Grice, a geochemist and Australian Research Council Laureate Fellow who directs Curtin's WA-Organic and Isotope Geochemistry Centre, calling it "a landmark discovery" that "opens exciting new avenues for molecular-level paleontology." The international team, which also included researchers from Japan, Brazil's National Museum and Johns Hopkins University, says the mineral hausmannite appears to have acted as a kind of natural time capsule, stabilizing the cells after the animal was likely buried quickly in low-oxygen, microbe-rich sediment.
If confirmed, the discovery would upend the long-standing assumption that hemoglobin-derived molecules cannot survive across geological time, and the team says it could point researchers toward overlooked molecular information in other fossils — even, they suggest, informing where astrobiologists search for signs of ancient life elsewhere in the solar system.
Not everyone is persuaded. Paleontologist Mary Schweitzer, whose own decades of work on soft-tissue preservation in dinosaur bone helped open this entire field of study, has said the new findings do not meet the standards her field has established for confirming genuine fossilized blood cells, according to Smithsonian Magazine. The debate reflects a long-running tension in paleontology between researchers eager to extract biological information from ancient fossils and skeptics who argue that mineral artifacts and contamination can easily mimic the signatures of real biological material.
Either way, Grice's team says the specimen is prompting new scrutiny of museum fossil collections long assumed to hold nothing but stone.
