Re: Ceratops (was RE: Glishades ericksoni, ...)

[Tim Williams <tijawi@yahoo.com>]

Paul P <turtlecroc@yahoo.com> wrote:

> _Ceratops_ is actually excluded from 
> all proposed definitions of Ceratopsidae
> 
> ? If so, that's only because it's a nomen dubium. 


Exactly.  There's no doubt that _Ceratops_ was excluded from the phylogenetic 
definition of Ceratopsidae for good reason.  Irrespective of whether _Ceratops_ 
is a nomen dubium (i.e., the type material is non-diagnostic at the genus 
level), the fragmentary nature of the material makes _Ceratops_ a very poor 
taxon to define a clade with.  

However, because _Ceratops_ may not even belong to the 
Chasmosaurinae+Centrosaurinae clade (Ceratopsidae), _Ceratops_ is also a poor 
choice to name this clade after.  If we can't be sure that _Ceratops_ belongs 
in Ceratopsidae (and we can't), then why call this clade Ceratopsidae at all?
 

> Btw, "Ceratopsinae" is not used by ceratopsian experts.
> They 
> already and always have used Chasmosaurinae. See
> Dinosauria, 
> Dinosaur Systematics, etc.


Yes.  My beef is more with Ceratopsidae, a taxon that (despite being named 
after a dubious genus) does have general acceptance.  Perhaps we should re-name 
it Centrosauridae...?

   
> As for Ceratops, it may indeed be Avaceratops (or vice
> versa, 
> actually), but that's impossible to demonstrate because 
> Ceratops only includes two horncores and an OC, and as 
> Tom pointed out, there are other taxa with similar PO 
> horn morphology (though only one or two). 


Yes, the name _Ceratops montanus_ is really only kept alive for bookkeeping 
reasons.  On any objective analysis, _Ceratops_ is a nomen dubium.


Cheers

Tim