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Re: New references



Mickey Mortimer (Mickey_Mortimer111@msn.com) wrote:

<I refer to such depressions as fossae, as opposed to fenestrae, which
would actually fully penetrate the bone.  Just as the antorbital fossa of
Erlikosaurus or Chirostenotes has a well defined overhanging rim, so does
the maxillary fossa of Byronosaurus.  It doesn't make any of them
fenestrae.>

  I would not refer to such a thing as semantics, but be this as it may. A
fenestra is defined, as in Wedel et al., on their analysis of sauropod
cervical pneumatization patterns, as a pocket with a sharply-defined rim
that encloses, at least partially, the entrance as smaller than the pocket
within. Since the internal structure of the antorbital cavity is a
diverticulum and therefore not an open structure, that penetrates the
external maxilla anyway, then one can very easily see how this
diverticulum would be bounded medially by cartilage (as it has been
assumed to in other taxa, and shown in verious carnosaurs as bone, such as
in *Sinraptor* and *Tyrannosaurus*) which could just as easily ossify. The
CT scans of the skull of *Byronosaurus* show that these medial walls are
inset fairly deeply and that the maxillary fenestra is the entrance to a
maxillary pocket or "bulla," but this hardly means it was not a fenestra
when penetrating the lateral maxillary wall.

  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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