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Re: *Utahraptor* and Polyphyly of Recent Dromaeosaurids

"Jaime A. Headden" wrote:

>   At one point, I, too, considered it to be a young or basal
> tyrannosaurid, for certainly this is what prompted Matthew and
> Brown to place it in "Deinodontidae" with *Albertosaurus* and
> other tyrannosaurids. The teeth are especially similar in this
> regard, as is the robusticity of the jaws.

    The dentition of _Dromaeosaurus_ are actually quite distinct from
anything currently being referred to "tyrannosaurids"

>  Arguing for a monophyletic Dromaeosauridae:
>   7. form of the denticles of the teeth;

    This character may or may not turn out to be robust and valid.  At
this point I am voting for yes, IF the proper homework is done.
However, the amount of homework is rather substantial...and to my
knowledge, there is currently not a single paper anywhere in the world
where the morphology (not size per unit distance) of theropod denticles
has been systematically examined in the detail necessary to substantiate
the above statement.


Josh Smith
Department of Earth and Environmental Science
University of Pennsylvania
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