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RE: What group has the most work that needs to be done?



Granted pachies had to evolve from another dinosaur group. But to unite
them with ceratopsians because they have an expansion of the rear
cranial table is very weak. The most primitive of ceratopsian frill is
structurally different from that seen in pachies. The skeleton of
pachies don't figure much in many cladograms, but pachies are more than
their skulls. I would argue that there are more similarities between the
pachy skeleton and other ornithopods (such as Thescelosaurus). Yes, I
know that the argument could be made that these similaries are
plesiomorphic, but that is a perspective issue and may not hold true
relative to Heterodontosaurus-Lesothosaurus (OK, I admit cheating,
haviing looked at Mike Triebold's unpublished pachy skeleton).

Ken

 

> -----Original Message-----
> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu] 
> On Behalf Of T. Michael Keesey
> Sent: Thursday, April 21, 2005 12:08 PM
> To: dinosaur@usc.edu
> Subject: Re: What group has the most work that needs to be done?
> 
> On 4/21/05, Ken.Carpenter@dmns.org <Ken.Carpenter@dmns.org> wrote:
> > Hmm. OK, missed those, but not on cladograms in pachy or 
> ceratopsian 
> > chapters. I still stand by my statement. The group is too weakly 
> > supported.
> 
> Which alternate grouping do you find more strongly supported?
> (IIRC, doesn't The Dinosaur Heresies show pachys allied with 
> thyreophorans?)
> 
> --Mike Keesey
>