Scientists have detected chemical traces of dinosaur blood in 115-million-year-old fossilized bones, finding evidence of heme-derived molecules and amino acids associated with collagen. Led by Curtin University, the international study suggests that some fragile biological materials can survive far longer than previously thought and could influence both molecular paleontology and the search for evidence of ancient life beyond Earth.
Ancient blood molecules preserved in dinosaur bones
The research team found chemical evidence of fossilized red blood cells and blood-related molecules in the remains of Aratasaurus museunasionali, a carnivorous theropod dinosaur discovered in northeastern Brazil. The findings, reported in the Proceedings of the National Academy of Sciences, also included amino acids related to collagen, an important structural protein in bones and other connective tissues.
The study provides the first definitive chemical confirmation of a molecule derived from hemoglobin within the red blood cells of fossilized dinosaurs. Earlier research had identified structures resembling blood cells in ancient fossils, but scientists had not conclusively demonstrated that these structures contained the specific molecular remnants of blood.
When the researchers examined the dinosaur’s limb bones, they found large numbers of petrified red blood cells in the vasculature—the small passageways where blood vessels once existed. Chemical analysis showed that heme molecules, components of hemoglobin, had been preserved. Hemoglobin is the protein that enables red blood cells to transport oxygen.
The presence of these molecules offers direct chemical evidence that the fossils contain remains of ancient blood. It also indicates that some biological materials once considered too fragile to survive for millions of years may still be detectable under exceptional conditions.
The research was led by John Curtin Distinguished Professor Kriti Grice, founding director of Curtin University’s WA Center for Organic Isotope Geochemistry and an Australian Research Council Awarded Fellow.
“It is surprising that we have detected intact heme-derived molecules in 115-million-year-old red blood cells. This is a truly groundbreaking discovery,” Professor Grice said.
“This not only expands the known blood fossil record, but also provides a direct molecular window into the physiology of long-extinct animals, so we may better understand them and the world they lived in.”
How the dinosaur blood may have survived
The exceptional preservation appears to be associated with hausmannite, a mineral that helped stabilize the fossilized blood cells and protect their molecular components, including collagen-related amino acids, over geological timescales.
In effect, the mineral may have created a natural time capsule, preserving microscopic evidence of dinosaur life long after the animal died.
The circumstances of the dinosaur’s burial may also have been important. Researchers suspect that the animal was rapidly covered by sediment in an environment with little oxygen and substantial microbial activity. Such conditions may help preserve biological materials that would normally degrade and disappear.
The international research effort involved scientists from Curtin University’s School of Earth and Planetary Sciences, the Marine Research and Development Agency, the Brazilian National Museum, Cariri Regional University and Johns Hopkins University.
Implications for molecular paleontology
The findings challenge the long-held assumption that blood-related molecules, particularly those derived from hemoglobin, cannot remain preserved for such vast periods.
They confirm the survival of ancient blood components while also raising the possibility that other fossils contain molecular information overlooked by traditional testing methods.
“These findings challenge the long-held assumption that certain biomolecules, such as hemoglobin, cannot survive for long periods of time,” Professor Grice said.
“This opens up exciting new avenues in paleontology at the molecular level, allowing us to investigate the evolution of blood, metabolism and even activity levels in ancient animals.”
Such information could help researchers better understand how extinct animals functioned, including aspects of their metabolism and physiology that are difficult to reconstruct from bones alone.
Relevance to the search for ancient life
The significance of the discovery may extend beyond dinosaur fossils. Understanding how fragile biological structures can survive for millions of years could help scientists identify traces of ancient life in other extreme environments, including environments beyond Earth.
Professor Martin van Kranendonck of Curtin University’s School of Earth and Planetary Sciences said the findings were changing how researchers understood the preservation of molecular structures over vast timescales and under harsh conditions.
These insights could be valuable to astrobiology, the study of the possibility of life elsewhere in the universe. If biomolecules or their chemical signatures can persist for more than 100 million years under the right conditions, scientists may need to reconsider where and how they search for evidence of ancient life.
“This research illustrates how collaborative efforts across institutions, continents and scientific disciplines can unlock extraordinary insights into ancient life,” Professor van Kranendonk said.
The research was supported by the 2021 Australian Research Council Laureate Fellowship awarded to Professor Grice.
The study is titled “Heme signature of calcified red blood cells in blood vessels of a 115-million-year-old dinosaur bone” and was published in the Proceedings of the National Academy of Sciences.
Source: www.sciencedaily.com