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RE: tiny-armed theropods





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> Date: Mon, 17 Oct 2011 10:46:40 +1100
> From: tijawi@gmail.com
>
> Mickey Mortimer <mickey_mortimer111@msn.com> wrote:
>
> > And there we go with what Tim's argument also boils down to. You *think* 
> > that nomina dubia and other taxa of questionable identity
> > shouldn't be used for taxonomic purposes. Which is an opinion, but not 
> > backed by the ICZN. And the Phylocode isn't enforcable yet,
> > and doesn't have anything about nomina dubia in it either. So while you can 
> > have your opinion, it's not something that the community
> > has any need to follow,
>
> And yet.... the "community" does follow this convention.
 
 and by "community", do you mean the scientific community, or the public? (some 
of whom, as seen in the other thread, can say "marine dinosaurs" with a 
straight face)
:-)
 
 
> More recently, Wilson and Upchurch (2003) declared _Titanosaurus_ to
> be a nomen dubium. They accordingly argued that Titanosauridae should
> be abandoned. Now, irrespective of whether or not I believe
> _Titanosaurus_ to be a nomen dubium, it does seem prudent to *not*
> have a whole family based on a taxon that is questionable (i.e.,
> _Titanosaurus_). Sauropod workers should make the call about what
> family-level clades they want to use - not the ICZN.

 Does that apply across the board, or should they only have the right to defy 
the ICZN?   (when PhyloCode or anything else has the authority and weight that 
the ICZN presently has, will you say "we should let sauropod workers decide" or 
will you say "we have to comply" ?)
 
 
> > and doesn't concern me until you or Tim show that basing Troodontidae on 
> > ANSP 9259 (as in ANSP 9259 <- Dromaeosaurus, Passer)
> > has a realistic possibility of resulting in a clade that does not include 
> > troodontids as now conceived. That's the only thing to be worried
> > about when choosing a specifier for a clade (well, that and eponymity).
>
>
> No, because ANSP 9259 (the type tooth of _Troodon_) and _Passer_
> (sparrow) represent very different situations. We can be confident
> that _Passer_ (being based on literally millions of living specimens)
> is a crown bird. However, the phylogenetic position of a single tooth
> is always going to be precarious. Look at how closely the teeth of
> the unenlagiine _Austroraptor_ resemble those of _Spinosaurus_ -
> solely due to convergence. It is not too difficult to imagine a
> non-troodontid converging on the tooth morphology of _Troodon_.
 
I confess, I borrowed the TARDIS to go back and breed Tyrannosaurs so their 
babies would shed ANSP 9259 teeth.