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Re: Only One Triceratops Species??

Chris Ott wrote:

>For a more current reference, check out Cathy Forster's papers in JVP from
>1996.  She pretty much puts this whole controversy to rest.
        No controversy is entirely put to rest, especially not one
concerning alpha taxonomy of dinosaurs. While Forster's paper is one of the
latest studies, it is by no means the final word on the subject. Forster's
study is detailed in its evaluation of trends within Triceratops, but you
may find the context of other studies (e.g., Lehman and Ostrom and
Wellnhofer below) to be equally illuminating. Also, I'm pretty sure that
Dodson was more than familiar with her work (he was her PhD supervisor) when
he wrote his book, so I'm not sure your attribution of her paper as being
"more current" is entirely correct.

>Having worked
>on our Triceratops collection, our dozen or so partial skeletons fit well
>with her conclusions, as do at least three skulls that we haven't collected
        IMHO, you should be absolutely sure that you do not emulate
Procrustes, and "trim" your data to fit the model. Still, if you could
document this, it would be an important (and welcome, I'm sure)
corroboration of her findings.

>The paper basically takes all sixteen species that were named,
>and condenses them down to just T. horridus and T. prorsus.  Granted, she
>uses five characters to separate the two species,  but they seem to hold up
>quite well.
        As I recall, this study was conducted using the type specimens of
these species. As you well know, there are substantially more specimens out
there. That said, Forster's conclusions have not yet been challenged in
print, and so it is entirely up to the reader to evaluate her work. And, let
me be clear, it is not my intention to challenge her results, simply to
suggest a more critical reading of the literature. She may well be right,
and there is certainly room for more documentation of variability in

In addition to Dodson's views, check out:

LEHMAN, T. M. 1990. The ceratopsian subfamily Chasmosaurinae: sexual
dimorphism and systematics, pp. 211-229. In K. Carpenter and P. J. Currie
(eds.), Dinosaur systematics: approaches and perspectives. Cambridge
University Press, Cambridge.

OSTROM, J. H. and P. WELLNHOFER. 1990. Triceratops: an example of flawed
systematics, pp. 245-254. In K. Carpenter and P. J. Currie (eds.), Dinosaur
systematics: approaches and perspectives. Cambridge University Press, Cambridge.

        Hope this helps,

     Jonathan R. Wagner, Dept. of Geosciences, TTU, Lubbock, TX 79409-1053
  "Why do I sense we've picked up another pathetic lifeform?" - Obi-Wan Kenobi