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RE: Platecarpus tympaniticus - how to analyze a nomen dubium



Presumably, all major ceratopsian workers, including Forster and Dodson, HAVE 
looked at it. Dodson indicates so specifically in his book, _The Horned 
Dinosaurs_.

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)





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> Date: Tue, 21 Sep 2010 11:45:27 +0000
> From: keenir@hotmail.com
> To: david.marjanovic@gmx.at; dinosaur@usc.edu; tijawi@yahoo.com
> Subject: RE: Platecarpus tympaniticus - how to analyze a nomen dubium
>
>
>
>
> ----------------------------------------
> > Date: Tue, 21 Sep 2010 11:34:05 +0200
> > From: david.marjanovic@gmx.at
> > To: dinosaur@usc.edu
> > Subject: Re: Platecarpus tympaniticus - how to analyze a nomen dubium
>
> > *Ceratops*: has anyone even looked at the material in the last couple of
> > decades?
>
> Wait....if nobody's looked at the material, what has this discussion been 
> running on? (theory and ideals?)
>
>
>
> ----------------------------------------
> > Date: Tue, 21 Sep 2010 00:39:51 -0700
> > From: tijawi@yahoo.com
> > To: dinosaur@usc.edu
> > CC: tijawi@yahoo.com
> > Subject: Re: Platecarpus tympaniticus - how to analyze a nomen dubium
> >
> >
> > On Mon, 20/9/10, Michael Mortimer wrote:
> >
> >
> > > Tim Williams and I have been having quite a discussion on
> > > the DML this year about nomina dubia and how they should be
> > > treated. In the most recent JVP, Konishi et al. (2010)
> > > present an excellent example of my philosophy in this
> > > matter. Platecarpus tympaniticus is the type species of
> > > this well known genus of mosasaurs. It's based on
> > > fragments described by Leidy back in 1865 and ignored
> > > (Williston, 1898) or declared a nomen dubium (Russell, 1967)
> > > since.
>
>
> > But I think I know where you're headed here. I'm willing to give taxa based 
> > on fragmentary material a fair go. But... IMHO for the sake of taxonomic 
> > stability, such taxa should not give their names to higher-level taxonomy. 
> > This is because phylogenetic definitions of family-level clades include the 
> > name-giving taxon as a specifier (which makes sense), so we should choose 
> > name-giving taxa with care.
>
> Except none of us are precognitive - we don't know that better species will 
> be found. (we hope they will, but its not a guarantee)
>
>
> okay, let's say that, twenty years from now, I discover a dinosaur that is as 
> related to other Archosaurs as the Pangolins are to other Mammalia.
>
> When I and my co-describers name it, are we supposed to leave its 
> classificiation blank?:
> Kingdom: Animalia
> Phylum: Chordata
> Class: Reptilia
> Superorder: Dinosauria
> Order: Saurischia
> Suborder: ??
> Family: No clue
> Subfamily: did you not read the above?
> Genus: Allonovadontatherus
> Species: redcliff
>
> or should I fill in the blanks myself?
>
> (after all, neither I nor my co-describers know that, thirty years after our 
> publication, other Allonoadontatherids would be discovered, ones who better 
> show the relationship between their genus and other Dinosauria, and are get 
> names that sound better at the Family level)
>
>
> > > Incidentally, note that despite the fact Russell
> > > thought it was indeterminate within the genus Platecarpus,
> > > he retained it as the type species and kept other diagnostic
> > > species in the genus (like I'm recommending for
> > > Stegosaurus).
> >
> > This sounds like a very bad idea. Note that a fossil species is supposed to 
> > represent a distinct biological entity: a species. Maintaining a 
> > non-diagnostic type species solely for bookkeeping reasons strikes me as 
> > going against the entire purpose of biological taxonomy.
>
> as long as _Deinodon_ isn't discovered to be a crocodile, why does it matter 
> whether its or T.rex's name is on the Superfamily?
>
> (and don't say "because I'm more familiar with it"...because if that's the 
> answer, then how is paleontology supposed to survive your (far away) death?)
>
>
> > Taxonomy is not just about compiling lists. It's a way of classifying real 
> > species. If we cannot demonstrate that _S. armatus_ was a separate species 
> > (because the type material cannot be distinguished from diagnostic 
> > _Stegosaurus_ species) then the taxon is toast. P
> > here's no good evidence that this ever represented a real species, then let 
> > it go. There's no point converting it into an OTU, and running a 
> > phylogenetic analysis with it - all for the sake of keeping Ceratopsidae 
> > afloat. Sure, _Ceratops montanus_ might be a real taxon; but we're probably 
> > going to need more material to confirm this. Until this day comes (and it 
> > may never come), then let's stop playing silly-buggers and pretending that 
> > it's fine to have _Ceratops_ as an appropriate name-giving genus for an 
> > important family of dinosaurs.
>
> shouldn't the burden of proof lie on proving that _Ceratops_ *is not* a good 
> genus, rather than say "we should kill it because we're not sure" ?
>
> though, if it helps any, you can rename _Ceratopsidae_ the _Docimoidae_ so 
> that there's no ugly politics or bitter arguments over what to rename the 
> clade before conclusive proof one way or another arrives.
>