RE: What are some differences between Triceratops sp.

["Thomas R. Holtz, Jr." <tholtz@umd.edu>]

> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] 
> On Behalf Of KYLE GUISER
>
> Can I please get some help on the differences between 
> Triceratops prorsus and Triceratops horridus? Anything will 
> be great 0_o
> 
Forster's 1996 diagnosis for _T. prorsus_ was:
Frontal fontanelle absent, supraorbital horns relatively short with horn
length/basal skull length of 0.61 or less, rostrum relatively deep and shrot
with convexly rounded rostral margin.

In her study, _T. horridus_ was a "metataxon": it had all the traits shared
by _T. horridus_ and _T. prorsus_ but none of its own.

I think, however,  based on the ongoing ontogenetic work by Horner and
colleagues that these will be found as different growth stages of the same
species (_T. horridus_).

And I'm not sanguine about _Diceratops hatcheri_'s taxonomic future as a
separate species, either...

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661               

Faculty Director, Earth, Life & Time Program, College Park Scholars
http://www.geol.umd.edu/~jmerck/eltsite/
Fax: 301-405-0796

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA