Re: Falcarius utahensis (was RE: Newfound Dinosaur a Transitional Creature)

["T. Michael Keesey" <keesey@gmail.com>]

On 5/4/05, Tim Williams <twilliams_alpha@hotmail.com> wrote:
> 
> The anatomy of _Falcarius_ indicates that the teeth (small, leaf-like) and
> pelvis were among the first things to change in the transition from
> carnivory to herbivory in therizinosauroid evolution.  Nevertheless,
> "similarities between the dentition of the basal therizinosaur _Falcarius_
> and the basal oviraptorosaur _Incisivosaurus_, ... raises the possibility
> that the common ancestor of these clades [Oviraptorosauria,
> Therizinosauroidea] had already undertaken the initial steps in this
> transition."  But I wonder if this transition might have begun even earlier,
> based on the dentition of troodontids and the posterior shift of the pubic
> shaft that appears to be primitive for the Maniraptora.

Not to mention that the sister group to _Maniraptora_,
_Ornithomimosauria_, seems to have been omnivorous or even
herbivorous. Perhaps omnivory could be the basal state for
_Maniraptoriformes_, with dromaeosaurids (as well as tyrannosauroids,
if they are maniraptoriforms) exhibiting a reversal to carnivory? At
the least, maniraptoriforms appear to exhibit far more diversity in
diet than any other theropod clade, and perhaps more than any other
dinosaur clade.

So does _F. utahensis_ strengthen the case for _Oviraptorosauria_ and
_Therizinosauria_ as sister groups?

--Mike Keesey