RE: Ornitholestes and Enantiornis

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

T. Mike Keesey wrote:

>Wow, that's an interesting idea, although there are plenty of
>counterexamples (_Oviraptor_, _Buceros_, and _Casuarius_ are feathered
>and crested, _Megalosaurus_, _Torvosaurus_, and _Abelisaurus_ are not
crested and probably not feathered).

Yep.  As well has having numerous counter-examples, the idea is also
basically untestable.  Still, there may be a vague correlation of
"non-feathered+crested" / "feathered+non-crested".  Most modern birds also
tend to reduce the amount of skeletal or keratinous ornaments, for reasons
of weight reduction.

> > _Sinornis_ provides a much more stable anchor taxon for
> > Enantiornithes.  Anchoring clades in non-nominative taxa is actually
> > quite common, particularly when the nominative genus is poorly known,
> > and possibly non-diagnostic. Ceratopsidae, Hadrosauridae, and
> > Titanosauridae come to mind.

>It's a horrible, horrible idea, and the draft PhyloCode is rightly
>against it. 

And rightly so.  I think it's time we bid sayonara to "Ceratopsidae" and
"Hadrosauridae" - and perhaps "Troodontidae" as well.  "Deinodontidae" and
"Podokesauridae" have already fallen by the wayside due to the problematic
status of their nominative taxa.  The current situation is all incredibly
arbitrary.

> 1) Abandon the old name. Use _Chasmosauridae_, _Centrosauridae_,
> _Lambeosauridae_, _Saltasauridae_, etc.

I think this is the best solution - though I'm not sure what the
Hadrosauridae would be renamed.  Saurolophidae may have priority over
Lambeosauridae - assuming a monophyletic Hadrosauridae.

> I think I've also seen
> speculation on this list that _Ceratops_ may fall outside
> Clade(_Triceratops_ + _Centrosaurus_), or however _Ceratopsidae_ is
> defined.

That was probably my speculation (though I may not have been the only one).
If _Ceratops_ proves to be the same as _Avaceratops_, and _Avaceratops_ lies
outside the Ceratopsidae, then we have a problem on our hands.  Most likely,
_Ceratops montanus_ is a _nomen dubium_, and will therefore be excluded from
any nomenclatural tangles at the generic level.  For higher-level taxa, the
issue is a little stickier (as Mike mentioned).

>We've already seen _Ornithosuchus_ become a non-ornithosuchian, and if 
> we use Sereno's
> definition of _Ceratosauria_ (anchored on _Coelophysis_, IIRC), we might
> be seeing _Ceratosaurus_ become a non-ceratosaur!! 

The crocodiles and their friends (Suchia) are considered in some phylogenies
to be members of the Pseudosuchia ("false crocodiles").



Tim