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Re: pterosaur tracks from SVP



In addition to what Martin Brazeau is saying, I'd just like to add that
flight would be pretty inconceivable if the head could not be brought back
to somewhere above the shoulder girdle.  As we see in most if not all
Pteranodon and other large headed pterosaur reconstructions is a head held
way back resting that big heavy weight more central to the lifting area.  I
would certainly hope the neck vertebrae can manipulate by this much or we
would have a big spiralling mess on our hands.  Secondly, I heard of how the
plotting of the centre of gravity on these and other D. Henderson GIFs was
made taking into account the lighter volume made up by the lungs.  I wonder
if the pallate makes up another lightweight volume, whether this was
accounted for also, and how much of a difference it makes?
----- Original Message -----
From: Martin Brazeau <brazeaumartin@hotmail.com>
To: <bettyc@flyinggoat.com>
Cc: <dinosaur@usc.edu>
Sent: Friday, October 29, 1999 4:47 PM
Subject: Re: pterosaur tracks from SVP


>
>
>
> Betty Cunningham wrote:
>
>  >Dave Unwin and Don Henderson said that they tried 3 different body
> >positions-1 bipedal and 2 quadrepedal with different body orientations,
> >and that this was the only locomotion that came out with the animal
> >stable (balanced) out of all of them AND that matched the available
> >tracks AND that matched the possible articulations of the bones.
> >
>
> I appreciate the considerable power of this computer simulation. However,
I
> think, that even though the body orientation was the most stable of the
> positions chosen, it the possibilities themselves may not be the best. I
> found that there was a bias against the bipedal orientation.
>
> The posture of the bipedal model assumed the head way out in front of the
> center of gravity. I'm no physicist but I don't need a computer simulation
> to tell me that that is not going to work! ;-). I feel that the computer
> model should have had the the head oriented behind the center of gravity,
> something like a pelican.
>
> However, the major flaw in what I am saying is that I don't even know if
> pterosaurs can even assume that posture. So I raise that question of
wether
> or not that option was exhausted of all feasibility.
>
> I would just like to know what other people think/know. Anyone?
>
> Martin Brazeau
> 1st year Pure&Applied Science
> Heritage College,
> Hull Quebec
> CANADA
>
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