This looks like the right thread for this information I stumbled upon.
quote:
Bird-like respiratory systems in dinosaurs -- A recent analysis showing the presence of a very bird-like pulmonary, or lung, system in predatory dinosaurs provides more evidence of an evolutionary link between dinosaurs and birds. First proposed in the late 19th century, theories about the animals' relatedness enjoyed brief support but soon fell out of favor. Evidence gathered over the past 30 years has breathed new life into the hypothesis. O'Connor and Claessens (2005) make clear the unique pulmonary system of birds, which has fixed lungs and air sacs that penetrate the skeleton, has an older history than previously realized. It also dispels the theory that predatory dinosaurs had lungs similar to living reptiles, like crocodiles.
quote:
Some hollow bones are providing solid new evidence of how birds evolved from dinosaurs.
Bird Respiratory System
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