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Ornithopoda + (Heterodontosauridae + Marginocephalia) phylogeny



Greetings,

I've finally gotten a copy (although not pdf) of the Hongshanosaurus paper,
and it does include an explicit numerical phylogenetic analysis of
ornithischians that supports the phylogeny in the subject line.

There are only 7 taxa used, and 44 characters (all cranial), so this could
and should be expanded in the future.  However, here are the results, using
the taxonomy in that paper:

Lesothosaurus
Ornithopoda
        Hypsilophodon
        Neornithopoda (!?!?) (reference is too Cooper 1985, but I can't recall 
what
taxa were included in this...)
                Heterodontosaurus
                Marginocephalia
                        Stegoceras
                        Ceratopsia
                                Archaeoceratops
                                Psittacosauridae
                                        Psittacosaurus
                                        Hongshanosaurus

Ideally an advanced version of this analysis would be included many more
taxa (heck, we need one anyway to test most aspects of non-stegosaur,
non-ankylosaur, non-iguanodontian, non-ceratopsian ornithischian
interrelationships!!), but it is a good starting point.

Characters supporting Neornithopoda are:
*Preorbital length: 50-40%(1); less than 40%(2), basal skull length
*Jugal lateral expansion: present(1)
*Jugal lateral expansion position: from the caudal end of the jugal(1)
*Predentary tooth number: less than 5(1)

Can't say I much like a Neornithopoda that doesn't necessarily include
Camptosaurus, Iguanodon, and the hadrosaurids (i.e., the critters for whom
the clade was originally coined), but it isn't explicitly defined here.

Later,

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796