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Re: the bipedal ptero-challenge



aegyptiacus@aol.com wrote:
> 

> They can't flap their wings if they walk on their knockles, IMHO, even if 
> they do not or walk on hinlimbs, that's why.

Why do they need to flap their wings initially?
 
> To which HP Mike Taylor added :
> >Wow.  You've done a great build-up job on this Mystery Technique.  >Are you 
> >going to tell us what it is?  :-)
> 
> I'd like to know as well ;-)

I gave a brief description last night and a short additional response to
Mike this morning, and spent a substantial amount of time talking about
it at SSA '99.
> 
> OTOH, modern big fliers........have powerfull and relatively immense wings 
> compared to body size.

So does Quetz.

> I do know that the latter cannot take off without a bit (a lot?) of running 
> while flapping their wings.

Doesn't that presume that the big pterosaurs use the same launch
technique as the big birds?  Why should they, since they didn't have the
same bodyplan?

> And it's even worse for landing.

Not really.  Different strokes for different folks.  Take the different
body plan into consideration and figure out how they could have done it
using what they had available to them.

> I can't see a 12-15m of span animal just crouching on all fours and suddenly 
> take off with a jump.

That's your perogative.  How do you explain why maximum skeletal bracing
isn't aligned as would be anticipated for maximum flight loads?


> The wings must have been quite heavy and producing a lot of drag.

In the big Quetz, about 12 pounds of drag.  Considerably less for Qsp,
about 2 pounds of drag.  I don't know whether you would consider that to
be a lot or not.

> Another possibility is that those big guys were taking off from cliffs, by 
> diving.

That's true.  How many scores of miles did they have to walk first to
find those cliffs?  Quetz lived in a region of gently rolling,
relatively flat land that isn't likely to have had cliffs available.

> Still doesn't make them bipedal for me, as I stated before.

Nor me.

> My simple thoughts

Mine too.  I'm not capable of complex thoughts.
All the best,
Jim