Re: Unwin - 51st SVPCA

[Mike Taylor <mike@indexdata.com>]

> Date: Wed, 08 Oct 2003 23:16:09 -0500
> From: David Peters <davidrpeters@earthlink.net>
> 
>> David Unwin discussed pteraichnites.. that's pterosaur tracks to
>> the rest of us... and reviewed their occurrences, which clades
>> appear to be represented (_Purbeckopus_ might be an azhdarchoid...
>
> ...because???

... because it's so bloody huge!  Nothing else known has feet that
big.

David's talk was interesting.  He made the point that pterosaur tracks
are almost completely unknown for the first few tens of millions of
pterosaur evolution, when "rhamphoryncoids" were prevalent, and only
start to appear in numbers when the pterodactyloids take over as the
dominant pterosaurs.  He hypothesised that this was because
"rhamphoryncoids" were pretty much completely incompetent on the
ground, and so spent their non-flying time in trees, and that
facultative terrestriality was developed in the pterodactyloids.

Another possible interpretation that occurred to me (but I didn't dare
mention it at the SVPCA :-) would be that "rhamphoryncoids" when on
the ground were bipedal after and so left very different tracks that
are not getting recognised as pteraichnites.  I am sure someone will
now be kind enough to shoot that idea down in flames :-)

 _/|_    _______________________________________________________________
/o ) \/  Mike Taylor  <mike@indexdata.com>  http://www.miketaylor.org.uk
)_v__/\  The main difference between SunOS and SysV is that only the
         former has `compactify' in /usr/dict/words.

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