[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: four winged Archaeopteryx

Richard Cowen wrote-

The rigid furcula makes sustained flight difficult, but it doesn't prevent flight as far as I can imagine. So I concede that one to David Marjanovic. The flexing of the furcula acts to facilitate respiratory pumping, so helps to provide the fuel-burning capacity that powers sustained flight.

I don't follow the biomechanical/physiological side of things much, but has this been suggested before-
Is it possible the furcula took over the gastralia's role? Claessens (2004) suggested a ventilatory role for gastralia, and these are well developed in basal birds with robust furculae (archaeopterygids, jeholornithids, Sapeornis, confuciusornithids). Enantiornithine-grade birds have thinner furculae which nonetheless may have had limited flexibility due to their U-shaped cross section, and reduced gastralia. Once modern furculae evolve around the Yixianornis level, gastralia are reduced in size and number, and disappear by the time Gansus branches off.

Mickey Mortimer