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AGILISAURUS LOOKS MARGINOCEPHALIAN, BUT ALSO DOESN'T



I wrote a few days ago:
<< Agilisaurus has been classified as a fabrosaurid by some, and a
hypsilophodontid by others.  It's probably neither.  I am not sure what it
is, but it does have two characters which may lead on to believe it's basal
to Heterodontosauridae + Marginocephalia), those being somewhat fang-like
premaxillary teeth, and chisel-like cheek teeth. >>

George Olshevsky replied with:
<<I would go along with this 100%.>>

I now say this:
Although Agilisaurus has a few somewhat vague Marginocephalian characters,
like the fang-like predentary teeth and the chisel-like cheek teeth, the list
stops there.  It seems more derived than the basal ornithischians like
Lesothosaurus, stegosaurians and ankylosaurians (more on those later) because
it has five or less premaxillary teeth.  Those five teeth however fill the
entire caudo-rostral length of the premaxillary bone, unlike cerapods.  The
premaxillary teeth also are in the same horizontal plane as the cheek teeth,
and there is no diastema between the maxillary and premaxillary teeth, which
again points to relationships outside of Cerapoda.

Where does it lie exactly?  I'm not sure, but probably somewhere between
Lesothosaurus and Cerapoda.

Pete Buchholz
Tetanurae@aol.com