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Mickey Mortimer wrote:
As an aside, I don't agree with Sereno's revision of Tetanurae's
definition, adding Carnotaurus. As I wrote previously-The addition of
Carnotaurus as an external specifier by Sereno (2005) seems
counter-productive. Tetanurae was designed as a stem away from
Ceratosaurus, and abelisaurids were not explicitly discussed (having been
named only a year prior). In fact, technically, Indosaurus and Indosuchus
were classified as tetanurines by Gauthier (1986), since he lists them as
carnosaurs. If abelisaurids are megalosauroids (as in Paul, 1988), it
shouldn't stop megalosauroids from being tetanurines.
I disagree. I think adding an abelisauroid as an external specifier is a
great idea. Sereno added _Carnotaurus_" to ensure the stability of the
taxonomic content of the Tetanurae". The revised definition succeeds on
this point, and is much better in this respect than having only
_Ceratosaurus_ as the external specifier.
Although Gauthier (1986) was the guy who erected Tetanurae (and resurrected
Ceratosauria), abelisaurids (collectively or individually) had not yet been
exposed to a cladistic analysis. _Indosaurus_ and _Indosuchus_ might have
been classified as tetanurans by Gauthier, but he also treated
tyrannosaurids as carnosaurs. These were all a priori assumptions made by
Gauthier, and not actually tested.
Paul's (1988) classification of theropods was not cladistic. But if, for
example, a cladistic analysis does recover abelisauroids as the sister taxon
to carcharodontosaurids (as has come up), then Tetanurae would certainly
contract (and would probably be equivalent in content to Neotetanurae!). So
much for "taxonomic stability". But I would regard an
abelisaurid+carcharodontosaurid clade as a remote (but exciting)
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- Re: Tetanurae
- From: Michael Mortimer <email@example.com>