Re: Great in the air, not so good underwater

[jrc <jrccea@bellsouth.net>]

----- Original Message ----- 
From: "Michael Habib" <mhabib5@jhmi.edu>
To: <dinosaur@usc.edu>
Sent: Friday, December 08, 2006 6:50 PM
Subject: Re: Great in the air, not so good underwater


> Just the same, the running launch system has particular constraints and 
> benefits.

I agree.

> Constraint pretty clearly prohibits the forelimb-assisted launch cycle in 
> birds, and thus I doubt they'll ever produce volant members as large as 
> pterosaurs.

Yes.  I suspect that there may be constraints due to feather morphology as 
well, but that's just a hunch.

>  Stabilizing selection is probably hard at work, too, though: despite 
> denying some helpful launch modes, avian bipedality has some great 
> advantages.  In fact, being bipedal gives birds access to some launch 
> solutions denied to pterosaurs and bats; the ones I have in mind work best 
> at small to medium body sizes.

I agree.
> Still, I'll bet nothing beat seeing a Quetzalcoatlus catapault off the 
> ground...makes me sad that they're gone.

Or Hatzegopteryx, or Arambourgiana (sp??).  I tend to think of them as if 
they were still alive, and it jolts sometimes when I'm forced to think about 
their demise.  A cautionary tale for developing methods of meteor control 
during the next few centuries.

All the best,
Jim