Re: Sereno's (2005) new definitions

[Michael Mortimer <mickey_mortimer111@msn.com>]

David Marjanovic wrote-

> > Yes, I agree with what you're saying, especially since Allen (2004)
> > found it to be non-dinosaurian, whether including the skull or not.
>
> Ah! I completely forgot that one! What's the ref?

This is a job for... 
http://students.washington.edu/eoraptor/Coelophysoidea.htm#Procompsognathustriassicus

Allen, 2004. The phylogenetic status of Procompsognathus revisited. JVP 
24(3).

> > Maybe (Coelophysis bauri <- Liliensternus
> > liliensterni) would be better for Coelophysidae?
>
> If we don't want an undivided Coelophysoidea (which is de facto what we're
> having), then *Dilophosaurus* might be best...

Well, people have been using Liliensternus as a non-coelophysid coelophysoid 
for a while.  It's pretty universally agreed to be outside Coelophysis + 
Megapnosaurus.

> > Eh, we already have Pygostylia, Avebrevicauda, Euornithes and
> > Ornithuromorpha for those.  I prefer the historical precidence of
> > Gauthier's definition.
>
> But Gauthier himself does not :-)

Quite true.  But that's because of his obsession with apomorphy-based 
clades.

> And I don't want to have *Rahonavis* or *Shenzhouraptor* in there either.
> What about a node-based one anchored on *Hesperornis* or maybe
> *Apsaravis*? Some clade in that region needs a name anyway, and Ornithurae
> has been often used for suchlike.

For Hesperornis + Passer, I agree a name would be useful.  But why bother 
using Ornithurae there instead?  It's no more the origin of the 'bird tail' 
than (Passer <- Archaeopteryx) is.

> There will be an extremely easy way to organize such things: priority is
> based on the registration number and nothing else. So just register
> *Archaeopterygiformes* a few seconds earlier.

Will this be extremely easy?  Has anyone looked into the issue and decided 
on a hierarchy for potentially synonymous clades?

Tim Williams wrote-

> I can see the logic behind Sereno's definition of Coelurosauria: (Passer 
> domesticus <- Allosaurus fragilis, Sinraptor dongi, Carcharodontosaurus 
> saharicus).  Instability at the base of the Coelurosauria does not pose a 
> problem under this definition, and the Coelurosauria will always be assured 
> of excluding 'traditional' carnosaurs like _Allosaurus_.

Then why not use Ornithomimus?  It's derived enough to 'always' be a 
coelurosaur (excepting Barsbold's scheme which is no longer accepted by 
anyone), and has been displaced from the group FAR less than Passer (which 
some would still argue isn't a coelurosaur, as wrong as they are).

> I wonder if we should even bother trying to erect definitions that can 
> accommodate extremely heterodox or discredited groupings.

A good question.  Sereno seems to try to accomodate many potential 
topologies, even ones that haven't ever been suggested.  I figure we can 
safely ignore archaic things from say... before 1980?  But heterodox 
topologies can often unexpectedly reappear when new data or taxa are 
analyzed.  Witness Paraves, which was settling into a nice 
((Troodon,Dromaeosaurus)(Archaeopteryx,Passer)) consensus until these past 
couple months.  Or (Passer(Confusiusornis,Enantiornis)), which crazily 
appears out of Zhou and Zhang's new study.

Mickey Mortimer