Researchers have identified molecular remnants of blood, including heme, within the 115-million-year-old leg bone of a small, meat-eating dinosaur from Brazil. The find suggests that ancient fossils may preserve more biological information than previously understood.
The team from Curtin University discovered fossilized red blood cells containing heme, the oxygen-carrying component of hemoglobin, inside the vascular canals of the bone. This marks the first time scientists have chemically confirmed the presence of hemoglobin-derived compounds in dinosaur fossils.
Professor Kliti Grice, the study's lead author, stated that while dinosaur DNA was not recovered, the discovery provides a "molecular fingerprint of blood from an animal that lived 115 million years ago," indicating that fossils can retain a "chemical memory of the living animal."
The dinosaur, identified as Aratasaurus museunacionali, lived during the Early Cretaceous period and was found in the Romualdo Formation in northeastern Brazil. Researchers believe the preservation of these molecular traces was aided by rapid burial in a low-oxygen environment and the presence of hausmannite, a mineral that acted as a natural preservative.
The findings, published in the journal Proceedings of the National Academy of Sciences, could enable paleontologists to extract new biological and behavioral information from ancient fossils. However, scientists emphasize that this discovery does not bring the possibility of de-extinction closer. Professor Grice clarified that the research has not uncovered dinosaur DNA, which is fundamentally required for such endeavors. Experts agree that the prospect of finding usable dinosaur DNA remains extremely slim due to the vast timescale involved.
Aratasaurus museunacionali is classified as a small theropod, belonging to the same group that includes T. rex and modern birds. The known remains are primarily part of a hind limb, suggesting a fast-running predator. Scientists estimate the dinosaur, which was likely a juvenile or young adult, measured about 3.1 meters (10 feet) long and weighed approximately 34 kilograms (75 pounds).
The significance of the discovery lies in its demonstration that fossils can retain a substantial amount of biological information. Researchers are now looking for similar molecular traces in other fossils, potentially opening new avenues for understanding extinct creatures.