Re: Tetanurae

[Tim Williams <twilliams_alpha@hotmail.com>]

Andreas Johansson wrote:

> Presumably to prevent just that, Sereno's Taxon Search gives this
> definition of Tetanurae:
>
> The most inclusive clade containing Passer domesticus (Linnaeus 1758) but 
> not Ceratosaurus nasicornis Marsh 1884, Carnotaurus sastrei
> Bonaparte 1985.

Yes, I think you're right.  Previous definitions of Tetanurae (e.g., Padian 
et al., 1999; Wilson et al. 2003; Holtz et al. 2004) used only 
_Ceratosaurus_ as an external specifier.  Adding _Carnotaurus_ as an exernal 
specifier caters for the possibility that ceratosaurids and abelisauroids do 
not form a clade to the exclusion of birds and other 'traditional' 
tetanurans.  In this situation, the Abelisauroidea would presumably be the 
sister taxon to Tetanurae.  Under this topology, Holtz's (1994) 
Neoceratosauria (MRCA of _Ceratosaurus_ and Abelisauridae and all its 
descendents) would therefore include all of Tetanurae too.  Sereno (2005) 
rates Neoceratosauria as 'inactive', and AFAIK has no clade reserved solely 
for _Ceratosaurus_ and abelisauroids within traditional Ceratosauria (i.e., 
including coelophysoids), which is strange.  He may be assuming that the 
days of a Coelophysoidea-_Ceratosaurus_-Abelisauroidea clade are numbered - 
even though he found such a clade in his _Rugops_/_Spinostropheus_ paper.

Cheers

Tim

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