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Re: Fw: Theropods/pterosaurs -- pollinators?


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?