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The Fifth Cranial Nerve

  Thought I'd clarify the issue of the anterior lateral cranial
nerves in oviraptorosaurs and so forth.

  In maniraptorans, at least, there is one opening for the fifth
cranial nerve, the trigeminal, with oviraptorids and segnosaurs
bearing two separate openings. But let me clarify my position:

  In dromaeosaurids, there is a large single opening for the
fifth, a small one for the six, and a small one for the seventh.
The fifth has a very large opening, so it is not really
conceivable that there was a separate one for the first branch
(ophthalmic, V1). In troodontids and tyrannosaurids, there are
two. Itemirus as one opening for the three branches, as well
(Kurzanov, 1977; Currie, 1995). The fenestra pseudorotunda and
fenestra vestibularis of Barsbold & Osmólska (1999) is the
metotic fissure of Currie (1995).

  The issue in tyrannosaurs has been done with, and in
troodontids, Currie (1987) and Currie and Zhao (1994), as well
as Russell and Dong (1994) have dealt with the issue.

  In *Elikosaurus,* there is a sequence of four openings in a
row at the margin of the laterosphenoid and parabasisphenoid
bones... These correspond to the V1, V2+3, VII, and fenestra
pseudorotunda/metotic fissure, based on Oviraptoridae (Barsbold,
1977) and comparison to dromaeosaurids (*Velociraptor* and
*Dromaeosaurus*). In both *Erlikosaurus* and caenagnathoids, the
basicanium and neurocranium are fused. Most cranial elements are
firmly fused, in fact.

Jaime A. Headden

  Where the Wind Comes Sweeping Down the Pampas!!!!

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