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RE: On Conchoraptor?

> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]On Behalf Of
> Jaime A. Headden

>   The abstract really tells much of the story. In comparing the edocasts
> between Concho, Archie, and an ostrich, Kundrát finds that the oviraptorid
> brain is much more like that of the ostrich than is Archie's, implying it
> derived from volant ancestors. This is, of course, assuming that Archie didn't
> develop flight independantly from main-line, modern birds.

And several other issues: for example, what does the endocast of basal 
oviraptorosaurs (_Incisivosaurus_, _Caudipteryx_) look like?
And what of non-neornithine pygostylians?

>  Moreover, he
> uses rhea as a comparative body size to estimate body mass, and this seems
> particularly odd, as Concho is not a rhea, or even remotely similar (for
> example, the robust arms and tail, relative head size, neck shorter, and torso
> less compact with large pelvic anatomy, broad rather than conserved pes, 
> etc.).
Indeed! An odd choice.

> However, just
> looking at the endocast, we can say somethings with confidence: It had
> enourmous optic lobes. These lobes, adjacent to the cerebral hemispheres 
> (which
> themselves preserve a distinct fissure with large epiphysis), are only
> consistent with the enourmous orbits of oviraptorids, and argue that the eyes
> were not only large, but extremely acute. This despite the eyes having less
> stereoscopic overlap than do, say even dromaeosaurids or troodontids. So, we
> may be left with a question:
>   What use huge, powerful eyes that had limited overlap? Were they crepuscular
> animals, or nocturnal? Suited to doing their foraging (or hunting) at night,
> when other predators were tucked away cozy in their Denver the Lost Dinosaur
> comforters?

A very good question indeed! And true of a fair number of oviraptorosaurs.

                Thomas R. Holtz, Jr.
        Senior Lecturer, Vertebrate Paleontology
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
        Mailing Address:
                Building 237, Room 1117
                College Park, MD  20742

Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796