A breathtaking discovery

This is a specimen of , which lived 120m years ago, during the Cretaceous period, a mere 30m years after , the oldest known bird. It is reported this week in the by Jingmai O’Connor of the Institute of Vertebrate Palaeontology and Palaeoanthropology, in Beijing. Four other examples of are known, but this one is special because it includes a portion of one of the animal’s lungs. Soft tissue is rarely fossilised, but this individual seems to have been entombed rapidly in an oxygen-free environment in which flesh-consuming bacteria could not thrive. When Dr O’Connor and her colleagues studied the tissue using a scanning electron microscope they found that it looks similar to the lungs of modern birds. In particular, the microscope revealed circular cells with hollow centres that resemble the air capillaries modern bird lungs use for fast oxygen absorption. That suggests those capillaries evolved rapidly after and its kin first flapped into the sky.