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Re: Ceratosauria vs. Neotheropoda?



2009/11/21 Tim Williams <tijawi@yahoo.com>:

> In short, for clades such as Ceratosauria, Ornithosuchia and Pseudosuchia I 
> think the only nod we should make to "original meaning" is that the 
> definition reflects the intent behind the name.  Ceratosauria was clearly 
> intended to include _Ceratosaurus_; so even if ornithomimids had been 
> originally included in this group (they weren't), it shouldn't really matter 
> to the current definition.

Ok., I agree that it should be the thing to do to include Ceratosaurus
within Ceratosauria, and the same with Ornithosuchia. I think original
intent of names as Ceratosauria and Ornithosuchia was to include the
mentioned species of similar name. Also, original meaning would also
be against including crocodiles within Pseudosuchia.

I think that if Ceratosauria were originally considered to include
Ceratosaurus and ornithomimids, we can keep Ceratosaurus at the same
time we phylogenetically make Ceratosauria as inclusive so that
ornithomimids enter there also, and not enter in contradiction with
the intent of including Ceratosaurus. Or would you say common use
(e.g., Ceratosauria ever since Gauthier, 1986) should be followed and
ornithomimids thus not included? (which seems good also).

Now, in the case we had some original meaning of Ceratosauria
including Ceratosaurus and ornithomimids, but excluding Allosaurus
(and if we want to follow original meaning instead of common usage) we
may do what Mike said and make a phylogenetic definition with internal
specifiers Ceratosaurus and Ornithomimus and external specifier
Allosaurus, and then make the name get destructed at
paraphyly/polyphyly.