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Re: D-sectioned teeth



Ken Kinman wrote-

>     I don't really know much about this character (D-sectioned teeth in
the
> premaxilla), except that it is mainly (exclusively??) found in
tyrannosaurs,
> ornithomimes, and troodonts.
>     Are there any interesting patterns in the numbers (or form) of such
> teeth in various taxa?  In other words, does this character hold
> phylogenetically valuable information (even though it would indeterminate
in
> toothless forms)?

Again, from my revised character list-
Question marks mean they are coded frm a data matrix.

 0- Stokesosaurus (Madsen, 1974)
 Compsognathidae (Ostrom, 1978)
 ?Proceratosaurus (Holtz, 2000)
 Richardoestesia (Currie et al., 1990)
 Caudipteryx (Zhou et al., 2000)
 ?Mononykinae (Holtz, 2000)
 Troodontidae (Currie et al., 1990)
 Dromaeosaurus (Currie et al., 1990; 1 in Norell 2001)
 Utahraptor (Kirkland et al., 1993; 1 in Norell 2001)
 Deinonychus (Ostrom, 1978)
 Saurornitholestes (Currie et al., 1990)
 Velociraptor (Sues, 1977)
 ?Icabodcraniosaurus (Norell et al., 2001)
 Sinornithosaurus (Xu and Wu, 2001)
 ?Archaeopteryx (Holtz, 2000, Norell et al., 2001)
 1- Eotyrannus (Hutt et al., 2001)
 Tyrannosauridae (Currie et al., 1990)
 Pelecanimimus (Perez-Moreno et al., 1994)
 ?- Ornitholestes (0- Holtz, 2000; 1- Norell et al., 2001)

Troodontids do not have D-sectioned premaxillary teeth.  They are
symmetrical, like tyrannosauroids, but their carinae aren't placed
posteriorly enough to be D-sectioned.  More of a cornered ellipse, like an
eye.  I'd be interested if anyone can clear up the state in Ornitholestes,
as the data matrices disagree (yes, Randall, a good example of the
importance of seeing specimens).  Despite what Norell et al. (2001) code,
Dromaeosaurus does not have such teeth, as shown by Currie et al. (1990).
Allosaurus doesn't either, don't know where David heard that.  We don't have
Dryptosaurus premaxillary teeth, so don't know if that genus had the
character.  According to Lambe (1917), all four premaxillary teeth and the
first maxillary tooth have this morphology in Gorgosaurus.  Eotyrannus has
at least one premaxillary tooth like that, but it seems the maxillary teeth
are all normal.  Apparently the premaxillary teeth and anterior maxillary
teeth of Pelecanimimus are all D-shaped.

Mickey Mortimer