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Re: Smallest carnivorous non-avian theropod



Ralph the Miller wrote:

<These animals may have been omnivores, and it is also
likely that different genera had somewhat different
diets (particularly in light of the Mongolian
varieties having teeth -- or something like teeth --
in the roof of the mouth, but no bristle-like teeth
contiguous with the rhamphotheca). Gregory S. Paul
also states in PDW that _Oviraptor_ had a rather
dicynodont-like jaw joint which would have facilitated
back-and-forth articulation.>

  By way of clarification...

  Cracraft (1971) was the first to report this, then
Paul (1988) and Smith (1992) repeated it. The trick
is, the articular and quadrate joint would not have
been limited in any movement by way of the bones: it
was up to the muscles and ligaments to hold the jaw in
whatever position was neccesary.

  Meanwhile, the two "teeth" in the palate of the jaw
are merely modified processes of the medial processes
of the maxillae that overlap the head of the vomer,
and are nearly in contact in the center of the jaw,
and are most efficiently oriented in the center of the
bony palate. Among other things, the jaw would have
centered anything in the jaws into these prongs upon
closing the jaws. They work almost just like the
vertebral prongs of *Dasypus,* the egg-eating snake.

  Check out ...
 
http://members.tripod.com/~Qilong/Oviraptors/eggeater.jpg

  ... for a side view of this happening. They are
singularly adapted for shellcracking.

  However, other portions of their anatomy (short [but
deep] gut, predatory manus in most species, very
strong forelimbs, neck, etc.) are marks of a predator,
and this is the short form.

<It has been pointed out that these animals were
larger -- and I would certainly think more massive --
than the compsognathids.>

  *Caenagnathasia* was about cat-sized, slightly more
massive than Compso, but about as long, based on
caenagnathids and oviraptorids, and Currie et al.
(1994) report a dentary fragment in the PIN collection
even smaller than Caenagna (from Kazakstan) that was a
definate oviraptorosaur.

===
Jaime A. Headden

"May I lure us, ere the mote ends us?"

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