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Re: Last of the Pterosaurs




Bryan McDevitt wrote:

> .....Quetzalcoatl. This huge creature, its head longer then
> a man,

If you're referring to the 7 foot long skull on the new full-scale
skeletal 'replicas' of Quetzalcoatlus northropi at TMM, Carnegie, and
elsewhere, I'm the one who provided many of the morphing dimensions we
used to blow it up from the smaller Quetzalcoatlus species, and though I
think the skull is probably a fair to middlin' approximation, I have
less than full confidence that the skull of the actual animal was
exactly the size or shape of the replica.

> was probably as big as a flying animal which it
> lived.

I think you are saying that Qn was the largest flying animal of all
time.  Maybe, maybe not.  Qn still had room for the shoulders, elbows,
and wrists to morph for greater loads.  It was not at the maximum
possible mass or span for pterosaurs, though so far I've not seen any
convincing evidence for larger spans in present finds.  I'm much
impressed with the shear load modifications between the proximal and
distal carpals as size increases from Qsp up to Qn, but even there,
there is room for additional capability without destroying the locus of
the wrist motion.

> Quetzalcoatlus was so big that it could not
> have taken off without help from the winds whistling
> through the mountains and canyons of Texas, USA.

Insofar as I know, so far all Quetz specimens have been found in areas
that were gently sloping to rather flat (perhaps 1% to 3% slopes on the
average), a considerable distance from both the nearest mountains and
the seashore.  Both Qn and Qsp appear to have been perfectly capable of
launching from flat land in a dead calm, even in today's atmosphere.
You can be reasonably sure that they didn't need help from winds to
launch.  In fact, launch loads appear to have been rather mild, perhaps
slightly over 2 g's, generating a forward speed greater than stall speed
prior to the first downstroke of the wings.

> Once
> in the air, it could glide on the air currents for a
> long time.

I would agree with this, during those times when atmospheric conditions
were appropriate.  Best L/D appears to have been on the loose order of
about 27:1 to 33:1, though slightly lower for Qsp.  In today's
atmosphere, sink rate at best L/D would appear to have been on the
approximate order of 105-120 feet per minute.

All the best,
JimC