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

[Tim Williams <tijawi@yahoo.com>]

Anthony Docimo <keenir@hotmail.com> wrote:

> So.....even if, early tomorrow morning, someone
> unearths a fossil identical to the _Ceratops montanus_ type
> specimen, it doesn't matter?   


That's right - it doesn't matter.  

Jaime hit the nail on the head when he said that you can't *prove* it's the 
same species.  This is because the type specimen lacks unique characters (or a 
unique character combination) that can be used to refer other specimens to it.

Let's say that the _Ceratops montanus_ type locality is re-discovered, and a 
complete skull is found with the same long, outward-pointing brow horns as the 
type specimen.  It is more than likely that this skull and the type specimen 
belong to the same species.  But because long, outward-pointing brow horns are 
not unique to _C. montanus_, we could not justify referring this skull to _C. 
montanus_.

In the event all this did happen, the best course might be to switch the type 
to the new specimen, which would become the neotype for _C. montanus_.  This 
would make _C. montanus_ a diagnosable taxon (assuming the new skull is 
diagnostic, which would be a fairly safe assumption).

I know sometimes these rules are skirted.  For example, the type specimen for 
_Troodon formosus_ is likely non-diagnostic.  _T. formosus_ has good specimens 
referred to it, which are used to diagnose the taxon.  But in most cases, 
genera and species based on specimens that are not diagnostic at the genus- or 
species-level have been abandoned as nomina dubia, such as _Iguanodon anglicus_ 
or _Deinodon horridus_.  In the case of _Iguanodon_, the type specimen was 
switched in order to maintain the validity of the genus.  This is an option for 
_Ceratops_.

   

Cheers

Tim