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Re: FOUR, THREE, TWO, ONE . . . PTEROSAURS HAVE LIFT OFF!
Dann, they could and most likely did stand that erect, though a Quetz would
stand only about 8 feet high at the shoulder and about 14 feet at the head
(vs. a giraffe's roughly 17 feet). A very heavy Quetz would have weighed
about 400 pounds, but average would most likely be closer to 330. Based on
the humerus of both animals and the back of the Hatz skull, a Hatz would
most likely be similar in height to a Quetz.
Re that launch scenario, it has been presented at conferences on occasion
for a decade now. Paul MacCready was the honoree at the SSA 99 conference,
and he asked me to give an hour long presentation on Quetz at SSA 99 in
Knoxville, TN in late February of 1999. I believe my presentation there
was the first time that the terrestrial quad launch scenario was presented
at a conference, and John Conway and I also did a time-stepping illustration
of a Quetz doing a terrestrial quad launch on a poster that we presented at
ICVM-7 in Boca Raton, FL in late July of 2004. I just looked back at a
letter I wrote to MacCready the week after the SSA 99 presentation, and note
that I commented to Paul therein about having done the quad launch
calculations the night before the presentation (which touched on a lot of
other things besides launch). I would say that from that time on,
terrestrial quad launch was based on calculation and was not a hypothetical
'just-so' scenario. My presentation at the Munich Flugsaurier conference
was to have been on the terrestrial quad launch, and when I let Mike know
that I wasn't going to be able to attend, he decided to modify his
presentation to include his take on it -- he had come up with the concept
independently of me, and was courteous enough to touch base with me prior to
describing it in his presentation. Mike has a lot of class -- not everyone
would have shown that courtesy. I want to reiterate -- Mike came up with
the concept independently of me and though we approached it from different
directions, our conclusions about it are virtually identical. That pleases
me -- there ain't no other feasible way for a big pterosaur to consistently
get off the ground at will.
BTW, if I remember correctly, Chris Bennett mentioned the possibility of
arboreal quad launch from trees in a paper he did back in the mid 80's.
That remains a viable scenario for smaller pterosaurs.
----- Original Message -----
From: "Dann Pigdon" <firstname.lastname@example.org>
Sent: Wednesday, January 07, 2009 6:23 PM
Subject: Re: FOUR, THREE, TWO, ONE . . . PTEROSAURS HAVE LIFT OFF!
Quoting Janet m vandenburgh <email@example.com>:
--Hopkins researcher reports that ancient flying reptiles used four legs
It's great to see research like this actually published, rather than the
sort of anecdotal back-and-forth
discussions such as we've seen here on the DML in the past (or elsewhere
on the internet). The only
surprising thing about this research is why it's taken so long for someone
to actually publish it (using
actual biomechanical calculations that is, rather than hypothetical
Does anyone have the full reference for this paper?
A modern-day man and giraffe, drawn to scale, flank the extinct pterosaur
known as Hatzegotpteryx. Unlike birds, pterosaurs used four legs to
themselves into flight, according to new research. Illustration by Mark
It's certainly an impressive illustration - but what is the likelihood
that Hatzegotpteryx could have
raised it's head as high as a giraffe can? Or that it could stand with
such straight limbs, for that matter?
I've always envisaged them as having a more bat-like stance on the ground,
with the neck at a much
shallowed angle. Although I imagine that wouldn't make quite as impressive