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

[Michael Habib <mhabib5@jhmi.edu>]

> As you say, it would depend upon all the above.  Argentavis could 
> barely get off at 75 Kg.  I have trouble imagining a 120 Kg volant 
> bird.

So do I.  I'm hesitant to say it couldn't happen; but I also cannot see 
how it could.

> I'd want to look closely at launch technique for a 90 Kg bird.  Once 
> launched, I think they'd be able to sustain flight OK.  I mention in 
> passing, that Qn and all similarly sized pterosaurs are far, far more 
> robustly constructed than Argentavis magnificens.

I'd definitely want to take a close look as well; that was a very 
rough, back-of-the-envelope estimate assuming that the bird is 1) a 
convective soarer with relatively low loading 2) extremely robust 
relative to Argentavis and the other known teratorns and 3) relatively 
long-legged (such as the the longer legged Rancho la Brea condors or 
modern caracaras, except obviously much more strongly built owing to 
larger mass).  To reach 90 kg, the bird would obviously also need a lot 
of directional selection for very large size, to the point of allowing 
very marginal launch ability.  Even with all of the above, I'm not sure 
it could happen.

Cheers,

--Mike H.