Re: Semi-Sprawled Sauropods (Was: WAVP Report)

[Stratigraphy@aol.com]

I have to agree with Ken for the most part...but math? Boring? Nah...

   As far as the semi-sprawling apatosaur forelimb I would have to say no.  
The Tate Museum has a complete forelimb that I have mounted more times than I 
care to imagine. For starters, the metacarpals form a horizontal platform, 
that articulated with a flat platform on the unla/radius.  The massive head 
of the ulna forms a nice wide flat surface (horizontal) for the humerus to 
articulate to.  Now, for the fun part.  The humerus attaches to the scapula 
in such a way that it is near vertical. The glenoid fossa (sp?) does not 
allow for motion in any direction other than anterior-posterior (no 
rotation).  Some may argue that it has some lateral motion as well.  I would 
not argue that fact to much, however it would not habitually walk with the 
humerus extended laterally, and its resting position would be vertical.  It 
is a gravipodal animal.  If you drew out a free-body-diagram, the force 
vectors of the sprawling vs. the non-sprawling diagram it will show the 
stresses received by that arm.  It is much more stable in the gravipodal 
position.  This is all from my own observations, I have not published any of 
this so take it for what it is worth.  
   If anyone wants to experiment, get on your hands and knees and put your 
weight forward.  Do this with your elbows locked, and with them flexed at a 
45, 65, and 75 degree angle(s).  There is a noticeable difference.    
   I was not following this thread previous to the new title (see header).  
So I am curious where Philip Platt gave his talk.  I don't recall this from 
SVP.  Is there a published paper on this?  That would be of interest as well. 
 That's my two cents.