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Citipati in the American Museum ...



Thanks to Tom for this notice,


Clark, J.M.; Norell, M.A.; & Rowe, T. 2002. Cranial Anatomy of *Citipati
osmolskae* (THeropoda, Oviraptorosauria), and a reinterpretation of the
holotype of *Oviraptor philoceratops*. _American Musuem Novitates_ 3364:
24pp.

  Here, the skull is described for GI 100/978, holotype of *Citipati
osmolskae* (Clark et al., 2001). This specimen is remarkable in preserved
the right epipterygoid, both coronoids, and both stapes. Similarly, both
hyoid ceratobranchials I are preserved, with the right one in natural
articulation. The skull is remarkably preserved and for the first time CT
scanning reveals the shape of the endocranium, and a pnuematic chamber
within the frontal that lies above the endocranium and is confluent with
both otic recesses. [pers. obs.: There is a suture visible between the
dentaries and premaxillae, indicating possible immaturity, but this is not
very telling in that sutures may fuse late in ontogent, well after the
onset of maturity.]

  AMNH 6517 is the holotype of *Oviraptor philoceratops*, and preserves a
relatively long rostrum (maxilla and dentary, premaxilla is only very
incompletely preserved). *Oviraptor* may be the most basal oviraptorid, as
the rostrum can be observed in one scenario to shorten progressively.

  There are some other oviraptorid notes to take heed: The big oviraptorid
which has been used to assess phylogeny in *Oviraptor philoceratops*,
specimen GI 100/42, is very similar to *Citipati osmolskae*, rather than
to *Oviraptor philoceratops*, in a number of cranial qualities, including
narial region and pneumaticity of the cranium. It is refered to *Citipati*
but it is not placed in any species, and the referral is tentative by the
hesitancy used in the paper (as a polarity between *Oviraptor* and
*Citipati*, and the abscence of apomorphies in *Khaan*, *Ingenia*, and
*Conchoraptor*).

  *Oviraptor mongoliensis* is noted for having a parietal crest as in
*Oviraptor mongoliensis*, but a short rostrum.

  There is more to say on the cranium of oviraptorids, especially in the
considerable similarity to dromaeosaurid crania. This includes all three
tympanic recesses, basisphenoid with struts as seen in segnosaurs and the
lateral depression of troodontids (but not dromaeosaurids). Two papers are
in press, one with the above authors on the skull of *Saurornithoides*,
and another from Norell, Makovicky, and Clark on the braincase of
*Velociraptor*, to be published in the Graves Museum proceedings: _Graves
Museum of Archaeology and Natural History Publications in Paleontology_ 2,
in press). These will considerably clear up cranial anatomy in recent
matrices, and are almost certainly the basis of the codings used in recent
AMNH phylogenetic analyses.

=====
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.

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