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Running pterosaurs



To Peter Bucholz:
The view that Pteraichnus traces were indeed made by pterosaurs was widely
accepted when Stokes (1957) first published, but then those claims were
dismissed after Padian and Olsen (1984) showed them to be crocodilian, not
pterosaurian.  Recently Lockley et al. (1995) reopened the controversy, and
I, for one, was a skeptic until I put my full-scale, articulated, manipulable
skeletons to the test. They passed and so now I am a believer.  Whether the
tracks (and they have been found worldwide now) are widely accepted as
pterosaurian I do not know.  I'd invite anyone who has read the paper to let
us know what they think.

Regarding comparative abilities in pterosaurs, Anurognathus, along with the
other reps. of Dimorphondontidae have relatively short wings and long legs.
 They were probably the most agile runners.  Rhamphorhynchus and kin were
just the opposite, long wings and short legs, and so were probably not great
runners.  Quetzalcoatlus was quite crane-like, with the exception that its
foreclaws were really quite robust, as were its non-flying fingers.  This
leads me to believe that Q. was hanging on to tree trunks, presumeably giant
evergreens that branch out only at the top.  Imagine that!  Or walking on all
fours in shallow streams plucking little critters seeking refuge in its
shadow.

Regarding the use of bipedality for running in lizards, yes, most do have to
get up to speed first.  Many can run from a standing start.  Frillneck are
unique in their ability to walk bipedally (See Shine and Lambeck 1989).  They
are very territorial and can see further by standing.  Frillnecks hate
natural history cameras and will chase one endlessly to the delight of all.
 Shine and Lambeck had to observe from a duck blind to catch frillnecks in
their act (that is, to see them behaving naturally without being seen first).


You say that pterosaurs had no reason to escape from enemies because they
could fly.  But what about their non-flying ancestors?  They were small and
flightless, like lizards.  Perhaps they were territorial and the main
competition was within a species.  

And then there is the question of how did they get to a sustained aerobic
metabolism (breathing while flying and running) when their eosuchian
lizard-like ancestors were anerobic while running and unable to breathe while
running?  [Lizards don't breathe while they run because their rib cage is
undulating preventing simultaneous expansion of both sides for inhalation.]

I do believe there were flightless pterosaurs (or rather, protopterosaurs).
 Sharovipteryx was one andthe trackmaker of Rotodactylus was another.  Both
have that unique fifth digit that bends under to form a prop.

David Peters DPterosaur@aol.com