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RE: Platecarpus tympaniticus - how to analyze a nomen dubium





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> Date: Tue, 21 Sep 2010 18:46:24 -0700
> From: tijawi@yahoo.com
> To: dinosaur@usc.edu
> CC: tijawi@yahoo.com
> Subject: RE: Platecarpus tympaniticus - how to analyze a nomen dubium
>
>
> Anthony Docimo wrote:
>
>
> > > *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?)
>
> Don't panic Anthony. Penkalski and Dodson (1999) provide a fairly detailed 
> description of the _Ceratops montanus_ type material. So does Ryan (2007). 
 
thank you.
 
> I'm not actually endorsing the view that _Ceratops montanus_ is a nomen 
> dubium (though I suspect it is). My argument is that given the meager 
> remains, _Ceratops montanus_ is a poor choice to name a family after. Both 
> the ICZN Code and PhyloCode agree that the family Ceratopsidae must include 
> _Ceratops montanus_. Thus, Ceratopsidae must be defined such that it includes 
> _Ceratops montanus_ as a specifier. But because _Ceratops montanus_ is 
> unlikely to contribute anything meaningful to a phylogenetic analysis, 
> _Ceratops montanus_ is unlikely to be used to anchor any clade (including 
> Ceratopsidae).
 
 here's my thought....
 
_Ceratopsidae_ was named for _Ceratops_, but now includes many other genera and 
species - who were placed in _Ceratopsidae_ because their describers felt they 
(the fossils) had features denoting their placement within _Ceratopsidae_.
 
So, can't we use the shared features of _Ceratopsidae_ members as an anchor?
 
(after all, unless we're going to find new homes for former _Ceratopsidae_ 
members, they'll all still be as related to one another as they were before  -- 
 whatever name they would go by, they would still have the same things 
separating them from, say, protoceratops's side of the clade)
 
 
 
> Ergo, _Ceratops_ should NOT give its name to any family-level clades (e.g., 
> Ceratopsidae, Ceratopsinae, Ceratopsoidea).
>
> > 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)
>
> Mike Taylor answered this better than I ever could, but it's worth 
> emphasizing the point that suprageneric taxa should not be erected for a 
> single genus. This used to be common practice, but it's totally unnecessary, 
> and frequently unhelpful.
 
 and the moral of the story:  don't make new ones.
 
 
> > 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.

> This assumes that ranks (phylum, class, order, etc) have some intrinsic 
> quantitative value. But they don't, and never have.
 
 that's why I phrased it as I did.
 
 
 
> Consider this: All those many bird "orders" (Struthioniformes, Falconiforme
> vialae. The Avialae is in turn a clade within the Maniraptora, which is a 
> clade within the Theropoda, which is a clade within the Saurischia. Yet, 
> Linnaean taxonomy lists Saurischia as an "order". Take-home message: Linnaean 
> ranks are a world of pain.
 
well until the PhyloCode comes online and replaces Linnaean taxonomy 
completely, we have to work with the Linnaean system.