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Re: bauplan convergence



At 02:25 AM 17/06/2000 -0700, Scott Hartman wrote:
This is important, because theropods and Archaeopteryx have deep narrow bodies, and long limb elements that keep would keep their center of gravity high off their footing, which doesn't help when recovering from a boffed jump to the next branch. I have no problem envisioning theropods climbing trees from a functional standpoint (grasping hands, lots of claws and what not), but there are simply no theropods (or Archaeopteryx) that show scansorial adaptations. So I doubt scansorial gliding was important in the evolution of avian flight.


I quite agree - but this does not mean that flight could not have evolved in trees, but without a gliding precursor. I posted a number of messages on this about five years ago, as a matter of fact: my basic point was that gliding and powered flight may be quite separate evolutionary strategies, with powered flight being more useful for maneuvering within trees by short upward leaps (eg to reach a prey item om a leaf or branch tip) without having to risk falling out of the tree. After all, really good gliders can cover great distances between trees at low energetic cost, so why fly if all you are trying to do is get from one tree to another?
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