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More pterosaur phylogeny - but not for wussies!



Pterosaur phylogeny

With regard to my comments on the DML Chris Bennett responded as follows:


'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.'


Yes, I agree completely with Chris, probably the most important difference 
between Unwin 2003 and Kellner 2003 is the distribution of character states 
concerning the notarium. However, if one compares our preferred cladograms 
carefully you find that the two distributions involve relatively few changes. 
To 
get from my preferred cladogram to Kellner's you only need to lump 
Ornithocheiroidea into a single clade with Dsungaripteroidea and Azhdarchoidea 
(as I conceive them) and leave Ctenochasmatoidea (= Archaeopterodactyloidea of 
Kellner) outside this clade. Then pull out Germanodactylus from 
Dsungaripteroidea, force it into Ctenochasmatoidea and thats about it - you can 
get from Unwin to Kellner in a few easy steps. 

Be that as it may, there are other problems with the clade supported by 
notarium 
characters. So far as I understand it, Tapejara does not have a notarium, 
although it is deeply nested within this clade and basal to other azhdarchoids. 
And, so far as I can tell, Haopterus, which seems to be a basal 
ornithocheiroid, 
also lacks a notarium. Note also that these taxa are represented by relatively 
small or medium sized forms - which fits with my explanation of the appearance 
of 
the notarium as size related. 

That said, I happily accept that the distribution and definition of notarium 
characters and the clade(s) they support are still major issues and need a lot 
more study. But, I'll stick my neck out and bet a bottle of champagne (with the 
first person to take up the challenge by emailing me directly - 
david.unwin@rz.hu-berlin.de), that ultimately this structure will prove to be 
homoplastic within Pterodactyloidea. 

Any takers? Or are you all wussies! 

Cheers,

Dave