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Re: Adaptive advantage (was Re: ABSRD BAND on Sinornithosaurus feathers)
I'm having difficulty with the scansorial ancestor. I'll bet Xu is already
sorry he said the pedal unguals of Microraptor looked like they might climb
trees. He didn't say anything about shoulder, knee etc regarding climbing.
>From a look at the fossil image, I can't see a scansorial animal any better
than a cursorial one.
Another issue: once the draggy leap-from-a-tree hunter was on the ground,
what would it do if it saw prey THEN. Go look for a tree to climb? How does
drag help now?
And another issue: cats hunt from the ground right? Even leopards, who
like to take prey into trees, do most of their catching from the ground. So
what is the modern example of a jump-from-a-tree predator?
All that said, I find it hard to ignore the fact that ALL the avian-like
theropods have very long legs. Why not some with shorter legs? If they were
busy climbing trees all the time, why retain very long legs? They ALL look
like terrestrial cursors to me. Thus, secondary flightlessness in maniraptors
or oviraptors asks for too much convergence for my liking, with everybody
somehow needing to be adapted to running, but a mysterious missing link
adapted to scansorial climbing in between.
I still think Ostrom had it exactly right from the first. He never thought
protobirds were runners who taxied for a take off. In his original papers, he
described them as leaping off the ground. Drag gets in the way of this.
Thomas P. Hopp
Author of DINOSAUR WARS, a science fiction novel published by iUniverse
Now Humans are the Endangered Species! http://members.aol.com/dinosaurwars