The earliest fossilized lungs have been found in an ancestral bird species. About 120 million years ago, the Archaeorhynchus spathula lived in what is today China alongside dinosaurs, before dying in a volcanic eruption. The newfound fossil is unusual for its preserved feathers and considerable soft tissue, which show that this primitive bird’s lungs closely resemble those found in living birds.
Modern birds have hyper-efficient lungs. Flying is a tough workout, and hyper-efficient lungs process oxygen quickly and with less effort, so that birds’ muscles can get enough oxygen during flight to keep going. This new fossil suggests such specialized lungs evolved earlier than previously thought.
