Re: Pterosaur size

[jrc <jrccea@bellsouth.net>]

----- Original Message ----- 
From: "don ohmes" <d_ohmes@yahoo.com>
To: <dinosaur@usc.edu>
Sent: Wednesday, December 13, 2006 11:13 AM
Subject: Re: Pterosaur size


> But then you would (wager they will eclipse Quetz)? I wouldn't. Unlike Jim 
> and Mike, I don't think today's environment could evolve a Quetz-sized 
> volant.

------- Why not?  Current atmoshperic conditions wouldn't stress either them 
or any of their ancestral line.......


> Or tomorrow's environment either.

That triggers a real big "Why not".

> In fact, I think the current size limit for flapping flight is below 
> Argentavis, and somewhat above the largest birds living...

I tend to agree with this particular statement, but what do avian limits 
have to do with pterosaurian (or bat) limits?

> even considering that some systems are superior to others, which to my 
> mind just increases the variance, but doesn't affect the slope of the 
> moving average. Just an opinion.

Some of us don't see a moving average in operation.
> Drosophilids optimize wingload in a few generations, in response to 
> latitudinal changes.

Individual birds do it in a few days, in response to changes in wing area 
because of the moult.  Birds that lose, say 30% of their wing area during 
the moult also tend to lose about 30% of their body mass (which does reduce 
their efficiency, but also allows them to continue to fly without much 
alteration of performance).