Re: Floating Pteranodon

["Chris Bennett" <cbennett@bridgeport.edu>]

----- Original Message -----
From: "Christopher Collinson" <Chris_Collinson@monarch.net>
To: "Dinosaur Mailing list" <dinosaur@usc.edu>
Sent: Friday, February 06, 2004 2:45 AM
Subject: Floating Pteranodon


> Occasionally, in past discussions regarding pterosaurs, the possibility
that
> Pteranodon could have fished while in a floating position has been
> mentioned. I am curious as how this would this have looked.

Most birds that swim regularly (e.g., ducks) trap air within their feathers
and float rather high in the water.  Cormorants swim regularly, but do not
trap air in their feathers, and so are low in the water, back more or less
awash and neck extended upward.  If you ever get to see a chicken swimming,
you will also see it low in the water.  Pterosaurs could not trap air in
feathers and there is no evidence that they could trap air in their "fur" so
they would most likely have been low in the water like a cormorant.


> Specifically how
> would the body, wings, legs, head and neck, have been oriented with
respect
> to the water line.

I think that the body would be more or less horizontal, wings folded but not
in a birdlike fashion.  Neck extending up and down to dip after prey.


> Also, how would the pterosaur have taken off again, from
> such a floating position?

It might turn toward the wind if there was wind, then extend wings, begin
flapping, and take off.  Jim Cunningham and I have disagreed on the question
of whether a run was needed for take-off [a disagreement that probably will
be settled by fisticuffs the next time we meet]. I think that that the
take-off in the first sentence might have required some assistance from
running hind feet, whereas I presume that Jim's vision of jumping into the
air would not require it if the first flap could get the body far enough out
of the water.  I have always had a problem with the "pluck fish out of the
water without getting your feet wet" scenario promoted by Wellnhofer.  I
presume that the scenario was developed at least in part because people did
not like the idea of pterosaurs landing on and taking off from water;
however, I think that they had to be able to land and take off because even
if they were only plucking fish, they had to be out over the water and close
to the surface.  If they couldn't take off, then every accident that dunked
them was fatal [Maybe that is why there are 1200+ specimens of Pteranodon
from the Niobrara!].  Some years ago there was a program on the television
about bats, which included a sequence showing a number of them feeding
around and under a bridge over a pond or stream.  Two bats collided and one
fell with a splash into the water.  Now I wouldn't think that bats were good
swimmers and they certainly do not seem to have a specializations for
aquatic locomotion, yet half a second later, there was another splash and it
was out of the water and right back flying after food as if nothing out of
the ordinary had happened.  Pterosaurs had to be able to do the same even if
they did not normally land on the water.  However, I go further and think
that Pteranodon probably regularly landed and rested on the water, much as
albatrosses do, and also landed when becalmed or the weather was too stormy
to fly.


> And lastly, would it have been possible for
> Pteranodon to dive into the water pelican style?

I have suggested (in Palaeontographica) that Pteranodon might have plunged
after prey.  Most people seem to think that Pteranodon was an incredibly
fragile creature; however, while working on my dissertation I went and
examined skeletons of pelicans in the osteology collections.  The bones of
the pelican's skull and axial skeleton are very lightly built and some are
translucent; in short, they look to be very fragile, yet one pelican (the
Brown if I remember correctly plunge-dives) while the other North American
species (the White?) does not.  It seems to me that if the fragile skeleton
of a pelican can withstand the stresses of plunge-diving, then the skeleton
of Pteranodon could as well.  The neck and notarium of Pteranodon are quite
robust and probably could have withstood a dive, so if I reconstruct a
Pteranodon plunge-diving, I envision it at a modest altitude, folding its
wings most of the way with the wingfinger extended straight back, and
straight going in.


Chris


S. Christopher Bennett, Ph.D.
Assistant Professor of Basic Sciences
College of Chiropractic
University of Bridgeport
Bridgeport, CT  06601
http://www.bridgeport.edu/~cbennett

"Savor the sun--but when the clouds come make animals"  (Hexum)