Overview
- The peer-reviewed Nature paper published Wednesday details three mummified Captorhinus from Oklahoma that preserve the oldest rib-powered breathing system in an amniote.
- Oil-rich, low-oxygen cave sediments at Richards Spur embalmed the reptiles, leaving three-dimensional skin, calcified cartilage and protein remnants nearly 100 million years older than any previously reported.
- Noninvasive neutron CT scans revealed soft tissues in 3D, and synchrotron infrared spectroscopy identified original organic molecules in bone, cartilage and skin.
- The fossils preserve a segmented cartilaginous sternum with sternal and intermediate ribs tied to the shoulder girdle, letting researchers reconstruct a complete rib-driven breathing apparatus.
- The team proposes this setup as ancestral for rib-assisted respiration in reptiles, birds and mammals, and the curated specimens at the Royal Ontario Museum invite further tests of that idea.