A fossil from Brazil's Crato Formation has yielded the first direct chemical evidence that blood molecules can survive more than 100 million years, according to a study published in the Proceedings of the National Academy of Sciences by a team led by Curtin University's Kliti Grice.
The researchers examined mineralized red blood cells preserved in vascular canals within a limb bone of Aratasaurus museonacionali, a small theropod dinosaur that lived roughly 115 million years ago in what is now northeastern Brazil. Using molecular analysis, they detected heme — the iron-containing compound derived from hemoglobin that gives blood its oxygen-carrying capacity — along with collagen-associated amino acids preserved within the fossil.
A find that challenges old assumptions
Previous discoveries of cell-like structures in dinosaur fossils had left open the question of whether they were genuine biological remnants or purely mineral artifacts that merely resembled cells. This study is the first to chemically confirm the presence of blood-derived molecules rather than just cell-shaped structures. "These findings challenge longstanding assumptions that certain biomolecules such as hemoglobin cannot survive deep time," Grice said.
The team, which included researchers from Curtin, Japan's JAMSTEC, Brazil's National Museum, Universidade Regional do Cariri and Johns Hopkins, proposes that rapid burial in low-oxygen, microbe-rich sediment, combined with the mineral hausmannite, helped stabilize the molecules over geological time. Curtin earth-sciences head Chris Van Kranendonk said the cross-continent collaboration "can unlock insights into ancient life."
Caveats and what's next
The findings rest on a single specimen, and the proposed preservation mechanism is described by the authors in hedged terms as likely rather than fully proven. No independent outside researchers have yet weighed in publicly on the result. The team says it now plans to re-examine other fossils for overlooked molecular traces, and sees potential implications for astrobiology — including questions about how long biological molecules might persist in extreme environments elsewhere in the solar system.
