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Re: Ceratosauria vs. Neotheropoda?



Augusto Haro <augustoharo@gmail.com> wrote:

> I suppose this later inclusion should not be considered as
> the original meaning of the name. If not, Ceratosauria would
> have to be phylogenetically defined as including both neoceratosaurs
> and tetanurans to cope with the original meaning.


I think you might be overstating the importance of "original meaning" in 
framing definitions and converting time-honored groups to clades.  There's no 
rule that says you *must* adhere to the original meaning of a name when 
converting it into a clade name.  


For example, the name Ornithosuchia was originally erected by Huene to include 
_Ornithosuchus_ (he erected Ornithosuchidae at the same time).  However, since 
then Ornithosuchia has been used for a much larger archosaur clade, and some 
definitions (e.g., "the most inclusive clade Aves but not Crocodylia") would 
actually result in clade Ornithosuchia excluding _Ornithosuchus_.


Personally, I would prefer that Ornithosuchia be defined such that it includes 
_Ornithosuchus_ - for the sole reason that the name was erected specifically to 
include _Ornithosuchus_.


Similarly, Pseudosuchia was erected specifically to *exclude* crocodiles (hence 
the name).  Yet some definitions of Pseudosuchia allow the 
crocodilian-containing clade Suchia to be a subset of Pseudosuchia, which 
strikes me as ridiculous.  


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. 


Cheers

Tim