Re: tiny-armed theropods

[Tim Williams <tijawi@gmail.com>]

Anthony Docimo <keenir@hotmail.com> wrote:


> Let me make sure I understand this:  the type tooth _Troodon formosus_ is not 
> the same as other known Troodon teeth (while being a
> likely member of the Troodont group)...
> ...yet despite its differentness, we shouldn't call it distinct?  Or we 
> shouldn't pay it any attention?


Not exactly.


The genus _Troodon_ is based on a single tooth.  If it turns out that
the tooth morphology of _Troodon_ is shared by two or more troodontid
species, then this morphology can no longer be considered unique (and
therefore diagnostic) for _Troodon_.  In this situation, _Troodon_
would have to be considered a nomen dubium.


My example of _Deinodon_ is to show what *could* happen to _Troodon_
(it hasn't yet).  _Deinodon_ was originally named from teeth that were
once considered distinctive.  However, later discoveries of
tyrannosaurid specimens showed that the tooth morphology of _Deinodon_
was actually common to several tyrannosaurid genera.  So the
_Deinodon_ teeth were therefore no longer distinctive (= diagnostic)
at the genus or species level.  Result: _Deinodon_ is a nomen dubium.


> (and if we're not going to bother with
> it, why not just sell it and the other nomia dubia - we already know there's 
> a market)


Yeah, very funny.    :-|


> I think I lost track of the thrust of the argument a few posts back.


For the woes of the genus _Troodon_, the description of _Talos_ is
worth a read (Zanno et al., 2011).





Cheers

Tim