Overview
- Researchers reported in PNAS that microscopic, oval cell-like structures inside the vascular canals of a 115-million-year-old Aratasaurus limb bone contain chemical signatures of heme, the iron-bearing part of hemoglobin.
- The team combined microscopy, elemental mapping and mass-spectrometry to link the cell-like structures to heme-derived molecules and amino acids associated with collagen, providing molecular evidence of blood and connective-tissue remnants.
- Authors propose the molecules survived because the animal was quickly buried in low-oxygen sediment and the manganese oxide mineral hausmannite precipitated in the tissue, which the team says chemically stabilized fragile organics.
- The paper and coverage stress clear limits: the analyses do not show intact DNA and the authors and outside experts call for independent replication and tightened contamination checks before the result is generalized.
- If confirmed, the finding could shift how paleontologists study physiology and prompt reanalysis of museum collections and fossil sites, and it may also inform searches for long-lived biosignatures in extreme environments beyond Earth.