Re: Andrew McDonald response re: European iguanodonts

[Tim Williams <tijawi@gmail.com>]

Jaime Headden <qi_leong@hotmail.com> wrote:

>   If it weren't for various actions to stabilize the name *Iguanodon* (type 
> species, type specimen) away from the teeth, we'd be dealing with another 
> taxon nominative of a group from which is
>  couldn't be reasonably compared, a la *Titanosaurus* and *Troodon*.


Agreed.  _Troodon_ is a ticking time-bomb.  The taxon _T. formosus_
was established upon a tooth; but numerous other remains have been
referred to this species, including a fragmentary skeleton named
_Stenonychosaurus inequalis_ and a dentary named _Polyodontosaurus
grandis_, from various horizons.  It's not likely that all this
material comes from a single species, which would mean that the _T.
formosus_ tooth morphology is shared by more than one species.  Under
these circumstances, either _T. formosus_ is a nomen dubium, or a new
holotype (neotype) would be designated in order to keep the genus
_Troodon_ as a valid taxon (as was done with _Iguanodon_).  If the
former, we would go back to calling the family Saurornithoididae.


A neotype (a partial skull) was also proposed for _Carcharodontosaurus
saharicus_, a taxon also founded upon teeth (now lost) (Brusatte and
Sereno, 2007).  The risk here is that if _Carcharodontosaurus_ became
a nomen dubium, the genus _Sigilmassasaurus_ would be available to
receive the diagnostic material referred to _Carcharodontosaurus_ -
assuming that the two are synonymous.




Cheers

Tim




Cheers

Tim