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Re: Platecarpus tympaniticus - how to analyze a nomen dubium



On Tue, 21/9/10, kelly wicks <kwicks78@gmail.com> wrote:


> Given that Ceratops montanus is one of very few, MT Judith River
> Formation dinosaurs that have brow horns, I would imagine there would
> be less discussion if there was a parietal to go along with
> the horn cores...


It certainly wouldn't hurt.  Especially if the parietal preserved diagnostic 
characters.  However, parietal morphology (like horn core morphology) is prone 
to variation within ceratopsian species, so an additional parietal might not be 
enough to diagnose the genus.


A ceratopsian bonebed (including nice skull material) was once reported to 
contain material that might belong to _Ceratops montanus_ (Trexler and Sweeney, 
1995).  The material was later assigned to a new genus, _Albertaceratops_ 
(Ryan, 2007).


If Marsh's _Ceratops_ type locality is ever re-discovered, and a complete skull 
is found that matches the morphology of the _Ceratops_ type specimen, then 
we're home and hosed.  


I guess I can address your other questions as follows:


The ICZN governs family-group taxa, such as family (-dae_), subfamily (-inae), 
tribe (-ini), and superfamily (-oidea).  The ICZN Code states that coordinated 
family-group taxa that share the same type genus must include the type genus.  
So Ceratopsidae (and Ceratopsinae) must include _Ceratops_, because these 
family-group taxa are based on _Ceratops_.


Ceratopsia and Ceratopsomorpha do not fall under the ICZN's rules, because they 
are not family-group taxa.  Ditto for Cerapoda.


PhyloCode (which has yet to be implemented) states that if a clade name is 
based on a genus name, that genus must be used as an internal specifier.  So 
again, not only must Ceratopsidae (and Ceratopsinae) include _Ceratops_, but 
_Ceratops_ must be included in the definition(s).  


Cheers

Tim

-- On Tue, 21/9/10, kelly wicks <kwicks78@gmail.com> wrote:

> From: kelly wicks <kwicks78@gmail.com>
> Subject: Re: Platecarpus tympaniticus - how to analyze a nomen dubium
> To: DINOSAUR@usc.edu
> Cc: dinosaur@usc.edu
> Received: T
ut of the shadows-
> 
> Ive been casually watching this thread...
> 
> Given that Ceratops montanus is one of very few, MT Judith
> River
> Formation dinosaurs that have brow horns, I would imagine
> there would
> be less discussion if there was a parietal to go along with
> the horn
> cores...
> 
> 
> 
> 1.  What are or were the nomenclature rules for naming
> Ceratops and
> Ceratopsia for Marsh, 1890?  What are the differences
> in the ICZN
> naming rules, then as compared to now, even with the over
> zealous
> cladists running around? :) Wouldnt Ceratopsia still
> maintain priority
> with the new rules because it was published first?
> 
> 
> 
> 2. How would Sereno's 1986 Cerapoda fit into this.
> 
> 
> 
> 3.  As almost all ceratopsian dinosaurs have some sort
> of "ceratops"
> in there name and being distinctly "horned" dinosaurs over
> any other
> current species, whose names and family go back 110
> years.  Are one of
> the few  well known and recognized family groups to
> the general
> public, how or and or why would this affect the naming and
> nomenclature or clade rankings, if any or even why bring it
> up?
> 
> 
> 
> 4. Even though "ranks (phylum, class, order, etc) have no
> intrinsic
> value" then why bother with looking at the family names
> and
> cladisitical analysis along with the phylogenetic
> code?  As we know it
> basically shows how everything is generally related over
> time, pending
> on your selected characters and analysis.
> 
> 
>