Preserved lungs in a Cretaceous bird?

[Halichoeres]

Bird fans will already know that birds have flow-through lungs, which allow them to bathe their parabronchi with oxygen-rich fresh air on each inhale and on each exhale, unlike the less-efficient tidal lungs of mammals. This fossil, one of several specimens of Archaeorhynchus preserves tissue that the authors of this paper claim is lung tissue.



Also, relevant to anybody doing a life reconstruction of this bird, the fossil indicates that they had a stiff pointed tail like a pintail, a morphology not previously known in a Mesozoic bird.

Paper (paywall): https://www.pnas.org/content/115/45/11555

Pop press write-up: https://www.sciencenews.org/article/first-scientists-spot-what-may-be-lungs-ancient-bird-fossil