Researchers find traces of red blood cells and heme in 115-million-year-old dinosaur bone

Researchers studying a 115-million-year-old dinosaur bone report they have found the strongest evidence to date of red blood cells in a fossil. The study, published in the journal Proceedings of the National Academy of Sciences, utilized microscopic imaging and chemical analyses to identify microscopic structures resembling red blood cells and chemical evidence of heme, a molecule in hemoglobin, within the bone.

The Discovery in Brazil

The fossil is a partial hind limb of Aratasaurus museunacionali, a theropod dinosaur from the Early Cretaceous. Paleontologists excavated the bone in 2008 at the Mina Pedra Branca site in northeastern Brazil, located within the Romualdo Formation.

Researchers found an abundance of oval-shaped microstructures within the bone's vascular canals—microscopic tubes that carry blood vessels and nerve fibers. The team also detected traces of manganese oxides, including hausmannite. According to the study's authors, the low-oxygen, stagnant water conditions at the burial site may have slowed decomposition, while the manganese oxides may have helped stabilize and preserve the cells.

Scientific Debate

While the study authors state this is the first time heme has been detected in situ, or within the structures themselves, in a dinosaur fossil, the findings are subject to debate:

• Structure and Shape: The researchers noted the structures differ in size and shape from red blood cells in living birds and crocodilians, though they cautioned that modern species may not be the best comparison for non-avian dinosaurs. Mary Schweitzer, professor emeritus at North Carolina State University, questioned if the shapes match living relatives, noting that dinosaur red blood cells should have a nuclear bulge, while these structures are concave.
• Chemical Composition: Schweitzer also questioned the significance of the hausmannite found in the bone, noting it is not detected in living red blood cells. Grice stated the team does not consider hausmannite an original component of the cells, but rather a mineral that formed during fossilization and helped preserve the structures.
• DNA vs. Heme: Timothy Cleland, a physical scientist at the Smithsonian Institution’s Museum Conservation Institute, noted that finding heme does not mean dinosaur DNA has survived, as the two molecules fossilize in different ways.

Why it matters

If these findings are confirmed in more specimens, it could allow scientists to ask more sophisticated questions about the physiology of extinct animals, such as how they transported oxygen and how their tissues functioned. Lead author Kliti Grice, an organic geochemist and John Curtin Distinguished Professor at Curtin University, stated, "The exciting implication is... that we now have approaches that can be applied to other fossils to ask how much original biological information may still be hidden within them."

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Sources

• cnn.com: Scientists find traces of red blood cells in a dinosaur fossil | CNN
• mynbc5.com: Scientists say they've found the strongest evidence yet of red blood cells in a dinosaur bone - WPTZ
• discoverwildlife.com: Scientists find red blood cells in dinosaur bone in "landmark discovery" | Discover Wildlife
• cirebontimes.com: Scientists Find Strong Evidence of Dinosaur Red Blood Cells
• mezha.net: Researchers say they’ve found the strongest evidence yet of red blood cells in a dinosaur bone
• journalarta.com: Dinosaur Fossil Offers Strongest Red Blood Cell Evidence — JournalArta Global

This article was drafted with AI assistance and checked against the sources above. Company claims are reported as claims. Cover image is AI-generated.