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Re: Torosaurus is Triceratops

Question for the folks who can see the paper and have the background education and experience to offer an answer.

What effects will this have on other cladistic analyses of ceratopsians?

On 7/13/2010 8:04 PM, Denver Fowler wrote:
MSU Press release:


Denver Fowler

----- Original Message ----
From: Denver Fowler<df9465@yahoo.co.uk>
To: DML<dinosaur@usc.edu>
Sent: Tue, 13 July, 2010 13:17:14
Subject: Torosaurus is Triceratops

Paper is out in the new JVP: on the Taylor and Francis website:


Torosaurus Marsh, 1891, is Triceratops Marsh, 1889  (Ceratopsidae:
Chasmosaurinae): synonymy through ontogeny

John B. Scannella; John R. Horner

Although they have been considered distinct genera for over a century,
ontogenetic analyses reveal that Triceratops and âTorosaurusâ  actually
represent growth stages of a single genus. Major changes in  cranial
morphologyâincluding the opening of parietal fenestrae and the  elongation of
the squamosalsâoccur rapidly, very late in Triceratops ontogeny and result in
the characteristic 'Torosaurus'  morphology. This report presents the results of

a 10-year field study of  the dinosaurs of the Hell Creek Formation in Montana
and is based on a  collection of over 50 specimens of Triceratops, including
over 30  skulls, which have been amassed in that time, in addition to
from numerous other North American museums. This large sample of  individuals
reveals the full ontogenetic spectrum of Triceratops.  The synonymy of
Triceratops and 'Torosaurus' contributes  to an unfolding view of extremely
reduced dinosaur diversity just before  the end of the Mesozoic Era

Denver Fowler