Study Reports Blood-Like Traces in Dinosaur Bone

A study published November 2 reports red-blood-cell-like structures and heme-related chemical traces in bones from a 115-million-year-old Brazilian dinosaur, though an outside specialist disputes whether the structures are blood cells. The findings concern limb bones of Aratasaurus museunacionali, a theropod that lived during the Early Cretaceous. Researchers found microscopic structures in vascular canals, the channels that carried blood vessels through bone, and detected compounds related to heme, an iron-containing component of hemoglobin that binds oxygen. The study, published in the Proceedings of the National Academy of Sciences, combines microscopic examination, mineral analysis and chemical testing. The research team says the structures’ shape and position within the bone, their mineralization and the associated heme-related chemistry support identifying them as fossilized red blood cells. The authors describe the combination as evidence of ancient biological material, not a preserved sample of liquid blood. The identification remains contested. Mary Schweitzer, a molecular paleontologist who was not involved in the study, says the structures do not convincingly match...