Re: *Utahraptor* and Polyphyly of Recent Dromaeosaurids

[Josh Smith <smithjb@sas.upenn.edu>]

"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.

-jb

--
Josh Smith
Department of Earth and Environmental Science
University of Pennsylvania
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