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Re: Arambougiania Citation Redux



T. Michael Keesey writes:
 > Also, I assume [_Pantydraco_] was named because including
 > _T. caducus_ in _Thecodontosaurus_ made _Thecodontosaurus_
 > paraphyletic? Is _Pantydraco_ closer to or further from _Sauropoda_
 > than _Thecodontosaurus_ is?

Further to Mickey's answer --

It's not yet possible to say.  The Pantydraco paper, Galton et
al. 2007, does not include a phylogenetic analysis of its own, but
says (p. 122):

        Yates (2006, 2007) made a comprehensive cladistic
        analysis of basal sauropodomorphs that, although
        _Thecodontosaurus antiquus_ and _T. caducus_ were
        included as separate terminal taxa, failed to recover
        a monophyletic _Thecodontosaurus_ in all of the most
        parsimonious trees.

The trees in the Yates papers are pretty well resolved (Yates 2006:9,
Yates 2007:31) and I think are identical.  They both show the two
_Thecodontosaurus_ species in a trichotomy with (Efraasia and more
derived sauropodomorphs) with _Saturnalia_ as the immediate outgroup.

This in itself doesn't seem a particularly strong reason to break up
the genus, and especially not by introducing such a crappy name as
_Pantydraco_, but I am guessing that Adam has a better analysis in
prep that shows a clearer separation, based on a stricter
interpretation of _T. antiquus_.

 _/|_    ___________________________________________________________________
/o ) \/  Mike Taylor    <mike@indexdata.com>    http://www.miketaylor.org.uk
)_v__/\  "I may be beating a dead horse here, but if you beat a dead
         horse hard enough, eventually it will move" -- Jake Wenger.




References
----------

Galton, Peter M., Adam M. Yates and Diane Kermack.  2007.
_Pantydraco_ n. gen. for _Thecodontosaurus caducus_ Yates, 2003, a
basal sauropodomorph dinosaur from the Upper Triassic or Lower
Jurassic of South Wales, UK.  Neues Jahrbuch für Geologie und
Paläontologie, Abhandlungen 243 (1): 119-125.

Yates, Adam M.  2006.  Solving a dinosaurian puzzle: the identity of
_Aliwalia rex_ Galton.  Historical Biology prEview: 1-31.  DOI:
10.1080/08912960600866953

Yates, Adam M.  2007.  The first complete skull of the Triassic
dinosaur _Melanorosaurus_ Haughton (Sauropodomorpha: Anchisauria).
pp. 9-55 in: Paul M. Barrett and David J. Batten (eds.), Special
Papers in Palaeontology 77: Evolution and Palaeobiology of Early
Sauropodomorph Dinosaurs.  The Palaeontological Association, U.K.