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        Aside from the very exciting news of a
psittacosaur with a hairy integument, I would like to
share some of my thoughts on the tooth structure and
predatory behavior of carcharodontosaurids. As I'm
sure many of you know, "carchs" have a number of
highly derived features that make them very unique
theropods. Among those features, the thin blade-shaped
teeth with odd horizontal wrinkles in the enamel, and
the reduced crown recurvature are most
distinguishable. Another is the sculpturing of facial
bones and the "squared" off symphysial end of the
dentary. While this may have been previously
hypothesized, I will procede with my idea of why these
features evolved and how they may have been used.
     I believe that the enamel wrinkles (which curve
toward the apex as they approach the anterior and
posterior carinae) serve to reinforce the denticles
(which are relatively small). The reduced crown
recurvature strengthens the tooth by lessening the
stress on the tips of the crowns (which would be
experienced in a typical theropod with very recurved
crowns, like Allosaurus). The squared-off dentary and
subparallel dorsal and ventral borders of the maxilla
(in Giganotosaurus) increased the depth of the
alveolus, thereby locking the teeth more firmly in
these bones. The cranial sculpturing may represent a
cornified covering of the skull, or at least thick and
tightly-associated scutes on the surface of the face
(like those drawn by HP Jamie Headden for Carnotaurus
and Majungatholus). So, what were these features used
for? I believe that carchs were evolving in response
to the giant titanosaurs that were developing bony
dermal ossicles. The reinforced denticles would pierce
the thick hides, the animal would then bite deeply
into its victim and pull back (this is were the
non-sigmoid neck and heightened neural spines come
into play) with its body, rather than its neck. The
toughened snouts of carchs withstood the ventral
pressure exerted during the bite by transferring some
of this energy into naso-lacrimal crests. An attack on
a sauropod by half a dozen carchs would have been an
awesome sight....lets hope someone makes a
computer-animated scene for a WWD-style documentary or
a JP sequel. I'm eager to hear your opinions on this
somewhat boring discourse of mine...


Waylon Rowley   

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