Scientists Find Blood Traces in 115-Million-Year-Old Dinosaur Bone From Brazil

Scientists have discovered microscopic structures resembling red blood cells and chemical traces of heme, a blood component, inside a 115-million-year-old dinosaur bone from Brazil, offering unprecedented insights into prehistoric biology without recovering DNA or liquid blood. The fossil belonged to Aratasaurus museunacionali, a small theropod from the Early Cretaceous, and researchers led by Curtin University detected heme B and altered versions within cell-like structures in blood vessel channels, with surrounding rock showing different chemical signatures to rule out contamination. The preservation may result from rapid burial on a microbial mat and a manganese mineral forming a natural time capsule, though experts question whether the structures are definitively red blood cells, and the discovery could prompt reexamination of museum fossils for hidden chemical evidence.