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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. I think 
that horns played a major rule in species recognition, even if there was a 
large amount of variability, like modern wildebeest (genus Connochaetes); my 
opinion (wild speculation?) is mainly based on Amotz and Avishag Zahavi theory: 
horn
 orientation and silouettes could have give to other member of the herd (at 
least if Triceratops was gregarious) or predators, indication of health, 
strength, or simply as mating signal. 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. Lehman contested this in his 1998 Pentaceratops paper, 
pointing out that such sinuses are size-related...this assertion was based on 
the comparison between various Pentaceratops sternbergi specimens and the huge 
OMNH 10165, wich I prefer to consider as Pentaceratops sp.


Lukas


> -- Nick Pharris <npharris@umich.edu> wrote:
> 
> > Quoting Ralph Miller <ralph.miller@alumni.usc.edu>:
> > 
> > > I haven't seen the article yet, but,
> > > having seen Goodwin present a cast of the skull
> > (which is on display in the
> > > traveling exhibition, Dinosaurs: Ancient Fossils,
> > New Discoveries"), I can
> > > vouch that young "trikes" were "cute."
> > 
> > Quite so.  Check out:
> > 
> >
> http://www.livescience.com/animalworld/060306_triceratops.html
> 
> ++++++++++++++++++++++++++++++++++++
> 
> I'd always thought that the horns of _Triceratops_
> played a more active role than in other ceratopians. 
> 
> To me it always seemed strange that it would evolve
> this incredibly heavy skull with no fenestration on
> the frill, if all it was doing was showing it off.
> 
> It should be interesting to read the ontogenetic
> reasons for why sex was probably not the key player in
> this.
> 
> Jason
> 
> "I am impressed by the fact that we know less about many modern [reptile] 
> types than we do of many fossil groups." - Alfred S. Romer
> 
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