Researchers identify possible dinosaur blood cells in 115-million-year-old fossil

Researchers from Curtin University identified what they believe are remnants of red blood cells in the limb bones of an Aratasaurus museunacionali fossil from northeastern Brazil.

The team analyzed a specimen from the Cretaceous Period, dating back 115 million years, using chemical and imaging techniques to examine the internal structure of the bone. The scientists found ellipse-shaped microstructures within the fossilized blood vessels.

Their analysis showed these structures contained iron, carbon, and nitrogen, which are components of heme, the protein in red blood cells that carries oxygen. The team also detected porphyrins, which are organic compounds that serve as precursors to heme. They used a laser light scattering technique to confirm these molecules and ruled out contamination from other substances like chlorophyll. The researchers suggest that a manganese oxide mineral called hausmannite acted as a time capsule to preserve these structures.

Because blood cells usually decompose within days, the team proposes that this specific mineral helped stabilize and protect the cellular components during the fossilization process. This discovery could provide a way to study the metabolism and activity levels of extinct animals. Some experts remain skeptical about the findings. Mary Schweitzer, a paleontologist at North Carolina State University, argues that the heme biomarkers were not localized only to the round structures but were found throughout the entire bone.

She also noted that the shape of the identified cells differs from those in living birds and reptiles. The researchers maintain that their conclusion is based on a combination of anatomy, mineralogy, and molecular chemistry.