Re: Bainoceratops & other basal neoceratopsians

["Jaime A. Headden" <qilongia@yahoo.com>]

George Olshevsky (Dinogeorge@aol.com) wrote:

<I think you can find the "jugal thingy" in most marginocephalians and
even in heterodontosaurians (one of the reasons I took heteros out of
Ornithopoda).  It became hornlike in ceratopians, e.g., psittacosaurs and
neoceratopians.>

  *Chaoyoungsaurus* lacks the "jugal thingie" which I assume is used to
refer to an apicular lateral and ventral expansion of the lateral jugal.
Not only does *Heterodontosaurus* have this, but so does *Orodromeus*.
*Orodromeus* is almost certainly an ornithopod and its placement if
questioned would call into question the methods of the supposer without
some _really_ good and overwhelmiong data; otherwise, one must assume the
"jugal thingie" is convergent. The problem is that the "jugal thingie" in
*O. makelai* and *H. tucki* are identical, if the jugals are shaped
differently on the ventral margin (unique to *H. tucki* however); the
"flange" is indentical in morphology and does not match any ceratopsian
morphology. It is lacking in pachycephalosaurs, as well. The "jugal
thingie" is useless to suppose *H. tucki* was a marginocephalian or non
ornithopod on this feature. However, as a recent or soon-to-be published
paper will show, there are many other non-jugal features that are useful
for suggesting *Heterodontosaurus* is a near-marginocephalian, but based
on the definition of Marginocephalia (*Pachycephalosaurus* +
*Triceratops*) it likely is not a marginocephalian.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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