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RE: Torosaurus is Triceratops



  *Torosaurus* and *Triceratops* are almost always recovered as each others' 
sister taxon in cladistic analyses featuring both of them (if not, in fact, 
always). The difference, as highlighted in some of the more recent works (e.g., 
Ryan et al. on *Albertaceratops nesmoi*) is that *Torosaurus* is almost always 
indistinguishable from *Torosaurus* save for the frill morphology. That last 
point is questioned in this paper. The only unresolved issue I can think of is 
the separation or subsumation of various *Torosaurus* and *Triceratops* 
species. *Torosaurus latus* was before *Ceratops horridus* or *Triceratops 
prorsus*, such that it would require re-coordination of the type species if 
*latus* is synonymous with *horridus* (which is required to lump *Torosaurus* 
and *Triceratops* together. This means *Triceratops latus* would be the new 
type species of *Triceratops* under the scheme of Goodwin and Horner (2006) and 
Scanella and Horner (2010). Note that I've not read the latest paper. If the 
authors do not subsume the species, or can discriminate them taxically, then 
the genera that contain them cannot be said to also be synonymous.

  I would _really_ like a copy of this paper if someone can so provide me!

Cheers,

Jaime A. Headden
The Bite Stuff (site v2)
http://qilong.wordpress.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 
Backs)





----------------------------------------
> Date: Tue, 13 Jul 2010 20:58:45 -0400
> From: dinosaur@gilvary.net
> To: dinosaur@usc.edu
> Subject: 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:
>>
>> http://www.montana.edu/cpa/news/nwview.php?article=8635
>>
>> ----------------------------------
>> Denver Fowler
>> df9465@yahoo.co.uk
>> http://www.denverfowler.com
>> -----------------------------------
>>
>>
>>
>> ----- Original Message ----
>> From: Denver Fowler
>> To: DML
>> 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:
>>
>> http://www.informaworld.com/smpp/content~db=all~content=a924306967~frm=abslink
>>
>>
>> Torosaurus Marsh, 1891, is Triceratops Marsh, 1889 (Ceratopsidae:
>> Chasmosaurinae): synonymy through ontogeny
>>
>> John B. Scannella; John R. Horner
>>
>> ABSTRACT
>> Although they have been considered distinct genera for over a century,
>> ontogenetic analyses reveal that Triceratops and “Torosaurus” actually
>> represent growth stages of a single genus. Major changes in cranial
>> morphology—including the opening of parietal fenestrae and the elongation of
>> the squamosals—occur 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
>> specimens
>> 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
>> df9465@yahoo.co.uk
>> http://www.denverfowler.com
>> -----------------------------------
>>
>>
>>
>>
>>
>>
>
                                          
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