Re: Pterosaur size (Was: Great in the air, not so good underwater)

[jrc <jrccea@bellsouth.net>]

----- Original Message ----- 
From: "don ohmes" <d_ohmes@yahoo.com>
To: <dinosaur@usc.edu>
Sent: Monday, December 11, 2006 10:34 AM
Subject: Re: Pterosaur size (Was: Great in the air, not so good underwater)


> PS-- How big would a ptero or bird have to be to elicit a "OK, these guy's 
> had to have had some help, because there is just no way in standard 
> atmosphere..."? Actually a serious question.

For an azdarchoid type morphology, looking at the differences between Qsp 
and Qn (which have no obvious indications that they might be different 
species -- differences in the presently known materials seem to be just for 
supporting the differences in size -- I wish more Qn materials were 
available).  I'd qualitatively say there's probably room for Qn to continue 
to morph to support a wingspan on the loose order of 13 meters in any 
atmosphere with a density within 10-15% of the current  atmosphere.  I'd 
expect the mass to rise with maybe the 2.7 or 2.8 power of the span, so I'd 
expect a 13 meter mass on the very loose order of 230-240 Kg, give or take 
maybe 30%.  A standing start, no-wind takeoff would not be difficult nor 
particularly stressful for an 11 meter Quetz in today's atmosphere.   I'd 
look askance at any estimate of span greater than that without personally 
examining the new remains to get a handle on how they done it.  Because of 
the more gracile differences in ornithocheirid shoulder and humerus 
morphology, I would not expect them to approach this span or weight.