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Larry Febo wrote:
-----Original
Message-----
From: Larry Febo <larryf@capital.net>
To: StephanPickering@cs.com
<StephanPickering@cs.com>;
dinosaur@usc.edu <dinosaur@usc.edu>
Date: Monday, May 20, 2002
8:29 AM
Subject: Re: Theropods/pterosaurs
-- pollinators? Unknown
wrote:
<It seems to me that pterosaurs
were "top heavy", and therefor clumsy at landings. I believe they were
probably restricted to landing on flexible cycad or palm branches rather
than the more stiff gymnosperm and angiosperm variety. I don`t think they
could make a precise landing on a stiff branch, as a bird (with well developed
acrocoracoid process) could. A bird could hover, and break its fall just
before landing.>
Please describe to me the technique
that Quetzalcoatlus northropi uses while landing on a flexible cycad
or palm branch.
<
...and, I must add (before someone
corrects me), in addition to the acrocoracoid process (which indeed pterosaurs
also have), it is the furcula with it`s energy storing capacity, and the
flight feathers with thier ability to provide air resistance on the downstroke,
and allow air to "pass through" on the upstroke that facilitate the ability
of small birds to hover. whereas pterosaurs most likely could not.IMHO...8^)>
Hummingbirds don't open their feathers on the 'upstroke' when they hover.
This is also true of other birds when using the 'momentum reversal' technique
for hovering. And it's quite possible that some small pterosaurs
could hover for short periods using camber inversion on the 'upstroke',
but I haven't attempted to calculate the hovering beat kinematics for small
pterosaurs, so that's just speculation on my part. Also as an aside,
Quetzalcoatlus species, with a head/neck length of about 8.2 feet
and a length from notarium socket to acetabulum of about 12.25 inches,
doesn't appear to have been 'top heavy'. Perhaps I'm missing something
here?
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