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Re: Pterosaur phylogeny



----- Original Message -----
From: <h0662eka@rz.hu-berlin.de>
To: <dinosaur@usc.edu>
Sent: Monday, November 24, 2003 12:50 PM
Subject: Pterosaur phylogeny


> On November 23 David Peters sent:
>
> 'Dear David,
> Alexander Kellner also presented a pterosaur phylogeny in the new
> Geological Society Buffetaut/Mazin volume on Pterosaurs. Could you
> please discuss the differences and similarities between your two
> cladistic views?'
>

I waited to see if and what Dave would comment on regarding the similarities
and differences of his and Kellner's analyses.  I had the privilege of
reviewing both analyses before publication, and whereas I can agree with
most of what Dave said, I think he failed to point out a major difference
between the two phylogenies in regard to the large pterodactyloids.
Kellner's phylogeny supports a monophyletic Dsungaripteroidea consisting of
all large pterodactyloids with advanced pectoral girdles (i.e., scapula
rotated so as to articulate with the notarium) as did my earlier analysis,
while Unwin's phylogeny views the advanced pectoral girdle as convergently
evolved in various clades of large pterodactyloids.  Note also that Dave's
use of the term Dsungaripteroidea differs from that of Keller in that he
view Germanodactylus as a dsungaripteroid and thus a close relative of
Dsungaripterus.

This may be a glass half full vs. glass half empty sort of quibble, but
while Dave thinks there is a lot agreement between the two phylogenies I see
that as a major disagreement.  The two suggest radically difference
evolutionary paths; on the one hand evolution of the advanced pectoral
girdle led to a major radiation of large pterodactyloids that essentially
replaced all other pterodactyloids, and on the other a gradual trend toward
large size and perfection of the pectoral girdle.

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)