Re: pteroid trouble

[jrc <jrccea@bellsouth.net>]

Several pterosaurs have an articular process on the inboard side of the 
preaxial carpal located about midway down the inboard face approximately in 
line anteriorly with the center of the anterior cotyle.  In some specimens, 
it is quite distinct.   That process seems to me to be the articular facet 
for the pteroid, and it solves a number of mechanical problems if it is 
indeed that.  I'm thoroughly convinced that Bennett is right.  The large 
sesimoid that articulates with the anterior cotyle seems to support a 
muscle/tendon that runs from the distal half of the humerus across the 
sesimoid to a point just outboard of the proximal end of metacarpal IV.  The 
outboard portion of that tendon between the sesimoid and MCIV seems to be 
responsible (among other things) for storing and releasing energy during the 
flapping cycle in order to appropriately modulate the angle of attack of the 
outer wing during the flapping cycle. The entire complex also sweeps the 
outer wing forward as the elbow is extended.
JimC

----- Original Message ----- 
From: "David Marjanovic" <david.marjanovic@gmx.at>
To: "DML" <dinosaur@usc.edu>
Sent: Monday, November 17, 2008 5:58 PM
Subject: Re: pteroid trouble


> > I just read the abstract and Unwin explicitly said the pteroid 
> > articulates with the anterior cotyle of the medial carpal (=preaxial 
> > carpal of Bennet, 2001). Is the "anterior cotyle" what Bennett (2007) 
> > calls the fovea that articulates with the large sesamoid?
>
> Probably -- but keep in mind that Unwin probably changed his opinion after 
> he submitted the abstract (the deadline for that was in May if I remember 
> that right!). In his talk he said (in Bennett's presence) he now agrees 
> with Bennett that the fovea articulated with that sesamoid and not with 
> the pteroid, and that it took him about a month to change his opinion 
> while he was looking at good specimens. However, he proposed a _third_ 
> hypothesis on where the pteroid did articulate.