Re: A New Hypothesis for the Origin of Flight?

[Waylon Rowley <whte_rbt_obj@yahoo.com>]

David Marjanovic wrote:

> Interesting idea, but I think the claws serve this
> function already, and better. Try HOBHY for 
> explaining why wings evolved :-)

HOBHY?  
 
> Basically the same as what has recently been
> proposed for bats. Very good, IMHO, because that 
> way you get trees-down without parachuting and 
> gliding.

Can you give a brief lay-out of this hypothesis? I
don't want to suffer under the illusion that I had an
original concept. 

> > Even if they did manage to get a good grip, 
> > powerful muscles would be needed to pull the body
> > onto the next branch [....]
> Possible. But very flexible arms and hands would be
> very advantageous here. 

What if both forelimbs secured a branch, and the
animal just hoisted itself right up onto it? It really
depends on how you climb, imho. You can have very
supple appendages, or stiff ones that provide more
stability. The stiffening of the body in a number of
avepectorans might solidify the body, reducing the
stresses on the skeleton incurred from moving in the
aforementioned way. 

> I don't see them in any described dinosaur (will be
> interesting to read what the aye-aye dino has... 
> no, that's not a prediction, I don't know it :-) )

Now that mention of the aye aye appears in DA, can we
discuss it openly? GSP doesn't give it much of a
description, but he does describe it nonetheless....
Always looking for a loophole :)  

> And still, it isn't reverted except in and very
> close to Pygostylia.

While I think this will change, I don't see how it
would impact the hypothesis....it's just another
climbing adaptation in more derived proto-avians.

> if *Eshanosaurus* is indeed a segnosaur,
> then oviraptorosaurs are at least as old as that 
> and had _plenty_ of time to reduce their halluces.)

Reverted halluces snag and are damage-prone in
runners. I'd expect them to be lost quickly.

> It's certainly testable, as it makes testable
> predictions. See above for some of my attempts at 
> tests. On the whole I'd expect a lot more climbing
> adaptations in those theropods, including basal
> birds. 

Well, new specimens are always being dug up in
China....we probably won't have long to wait.

Cheers,
Waylon Rowley


__________________________________________________
Do You Yahoo!?
Yahoo! Health - your guide to health and wellness
http://health.yahoo.com