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RE: Smallest Triceratops skull and other stuff



> -----Original Message-----
> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu] On Behalf Of
> heby@libero.it
> Sent: Tuesday, March 07, 2006 9:36 AM
> To: .. ...
> Subject: Re:Smallest Triceratops skull and other stuff
> 
> Really really cute. It's show some similarities with "Triceratops"
> eurycephalus, especially in the very high positioned orbit (a feature seen
> also in the Brachyceratops holotype), and slopig nasals. Obviously these
> are ontogenetic characters; however, the small specimen have well
> developed frill scallops and massive dentary, like adult T. prorsus and
> horridus, contrary to the nearly smooth squamosal and parietal of "T".
> eurycephalus (even if I believe in the post-mortem detachment of
> epoccipitals), and shallow mandibles. I wonder if these feature are of
> taxonomic value. Other characters of "T". eurycephalus, like the nearly
> closed jugal notch, the widened frill and the very long supraorbital horn
> are unique for the size of the specimen.

The unfortunate thing with "T. eurycephalus" is that the specimen isn't that
well preserved, and there is a bit of reconstruction on it. Also, the
scallops on the edge of the frill (and dentary proportions) are rather
variable between specimens.

> I'll wait for the paper to
> see if even this small "Tricky" have some sort of cornual sinuses and
> cranial sinus system, as the adult show.

Yes, they are present in juveniles--this was published as an abstract in
PaleoBios a few years back. Additionally, there will be an upcoming paper in
Journal of Paleontology (probably late summer/early fall) that discusses the
ontogeny and morphology of the "cornual sinuses" across chasmosaurines. A
more in-depth review of the cranial sinus system of ceratopsians is in
progress (probably more word on this will be presented at SVP this year). .


Andy