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More pterosaur phylogeny - but not for wussies!
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
differences of his and Kellner's analyses. I had the privilege of reviewing
analyses before publication, and whereas I can agree with most of what Dave
I think he failed to point out a major difference between the two phylogenies
regard to the large pterodactyloids. Kellner's phylogeny supports a
Dsungaripteroidea consisting of all large pterodactyloids with advanced
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
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
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.
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
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
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
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 -
email@example.com), that ultimately this structure will prove to be
homoplastic within Pterodactyloidea.
Any takers? Or are you all wussies!