Air-filled bones helped prehistoric reptiles take first flight

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Source: Science Centric

New international research involving the University of Leicester published today sheds new light on how prehistoric reptiles took to the air. In the Mesozoic Era, 70 million years before birds first took wing, pterosaurs dominated the skies with sparrow to aeroplane-sized wingspans. Scientists already knew, on the basis of fossil evidence from the wings, that these extinct reptiles were able to power their flight through flapping, but had little understanding of how pterosaurs met the high energetic requirements for flight.

The new research published in the journal PLoS ONE by researchers from the University of Leicester (UK), Ohio University (USA) and College of the Holy Cross (USA) explains how balloon-like air sacs, which extended from the lungs throughout the body, hollowing out many of the bones in the pterosaur skeleton, provide evidence for a remarkably efficient breathing system in these ancient beasts. As an important bonus, the pneumatised skeletal system and air sacs reduced the density of pterosaurs, allowing the evolution of the largest vertebrates ever to take flight, some reaching 10 metres in wingspan.

'We have identified the breathing system of a pterosaur. It's a surprisingly efficient mechanism with the same essential structure of a modern bird's lung apparatus - except 70 million years earlier' said study co author Dave Unwin, a palaeobiologist in the Department of Museum Studies at the University of Leicester.

Leon Claessens, an assistant professor of biology at the College of the Holy Cross and Patrick O'Connor, an assistant professor of biomedical sciences in Ohio University's College of Osteopathic Medicine, were inspired to conduct the study after viewing an extraordinarily well preserved rib cage of a pterosaur in Berlin in 2003. The fossil was shown to them by Dave Unwin of the Department of Museum Studies, University of Leicester, who was then curator at the Museum fuer Naturkunde in Berlin. Examining this specimen the three palaeobiologists realised that it could finally solve the mystery of how pterosaurs were able to power sustained flapping flight.

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