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Re: was: Pterosaur.net now: pteroid



That facet Chris and Jim are looking at on the preaxial carpal is not the facet 
for the articulation of the pteroid.

Absolutely NO specimens preserve the carpus articulated in this fashion. None. 
Zero. Send jpegs of exceptions if you can possibly find them. They don't exist. 
If they did, Chris would have included them in his  2007 paper. And try to 
imagine the big angle iron pteroid of Nyctosaurus articulated as Bennett 
suggests. So, it's back to the drawing board.

Given that it's not a bone/bone articulation, what is that little spot on the 
inboard preaxial carpal all about? Consider the possibility of a short ligament 
between the preaxial carpal and the pteroid, attaching at the pteroid bend and 
beyond. I'm sure no one will say these two carpals were NOT connected by 
ligaments. That's how they were connected. And that's why you NEVER see them 
articulated as Bennett imagined. You always seem them articulated (when they 
are articulated) pteroid to radiale. More details in the latest JVP. 


Okay, next subject, pteroid depression. 

The pteroid-radiale joint permits all sorts of movement -- in the absence of 
soft tissue. Add soft tissue and an airstream and its a different story. The 
tension at the leading edge of the propatagium restricted all movement at the 
pteroid tip. So what does that leave us? A pteroid that can rotate at its base, 
not like a swinging compass needle (in anterior view while flying), but like a 
radius/ulna. The whole pteroid could move up and down, never NOT pointing to 
the deltopectoral crest, but always parallel to its original orientation.

That work for you guyz? 

David Peters
St. Louis



On Jan 15, 2010, at 12:33 PM, Augusto Haro wrote:

> 2010/1/15 jrc <jrccea@bellsouth.net>:
>> There is currently an information embargo on the specimen I am looking at so
>> I can't name it, but it is well known and is not the one that Chris
>> described.
> 
> Thank you, no problem. I was specting for some basal pterosaur with
> the facet Chris Bennett found in pterodactyloids...