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Re: Rhamphorhynchus Perching???



Allan Smith wrote:

<...what would be the most widely accepted pose:

a). balancing on two legs
b). sitting on it's haunches and gripping the branch
with it's hands>

  Both would be technically possible. The long tail
would serve to balance equally a bipedal or
quadrupedal posture, more so the latter than the
former due to increased stability. Hoatzin chicks, a
good analogy in that case, can perch on a single
branch with their arms lateral to the legs for
support. The wings in rhamphorhynchoids would probably
be either up [folded] or backward and out
[semi-folded] depending on a balance. Remember the
skull and neck will be very light, and the center of
balance in these critters in about just posterior to
the shoulder socket. The short hind-legs in rhamphos
is long relative to the forearm length (sans humerus
of the foreLIMB) and this would equalized a
quadrupedal posture.

  Bipedal posture in some pterosaurs has been
hypothesized (Unwin, Bennett, and others, references
and abstracts published over the last couple years)
but quadrupedal would served better in most taxa
tested (Bennett et al., 1999, _JVP_ 19(supp. to 3.),
asbstracts). This may translate into any arboreal
posture, though I think these critters would have done
as well hanging squirrel-style from the sides of
trunks or rock faces. Flying squirrels who could truly
fly ... ? :)

=====
Jaime "James" A. Headden

  Dinosaurs are horrible, terrible creatures! Even the
  fluffy ones, the snuggle-up-at-night-with ones. You think
  they're fun and sweet, but watch out for that stray tail
  spike! Down, gaston, down, boy! No, not on top of Momma!

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