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Re: Carnosaurs and friends (was Re: Eustreptospondylus)

Tim Williams wrote:

>I don't like the name "Carnosauria".  Since it was first coined (?by
>Huene) I think it's essentially been redefined out of existence.  For
>the clade including _Allosaurus_, _Sinraptor_, _Yangchuanosaurus_,
>_Acrocanthosaurus_ etc I would name "Allosauria".  I would retain the
>term Carnosauria only for convenience - as a paraphyletic group
>embracing the Megalosauria and Allosauria.

Only one taxon has always been in Carnosauria as long as that taxon
has been in existence: Allosaurus.  Towards that end, and being partly
responsible for its "dismemberment", I (with Kevin Padian) formally
defined (within the phylogenetic taxonomy system) as Allosaurus and
all theropods closer to Allosaurus than to birds.  Thus, Carnosauria
is preserved as Coelurosauria's sister taxon.

Within Carnosauria is the node-based taxon Allosauroidea Currie et
Zhao 1994 (IGNORE the volume "year", it is 1994, not 1993!), the node
joining Sinraptor and Allosaurus.  Some carnosaurs, Monolophosaurus
and Crylophosaurus among them, may be outside Allosauroidea.

>Nick says:
>> Allosauridae [_Allosaurus_, _Saurophaganax_, _Giganotosaurus_,
>> ?_Chilantaisaurus_, and probably new stuff from England and France];

And the "headless wonder" from the Morrison.  Giganotosaurus seems fairly
convincingly to be a carcharodontosaurid.

>I like _Chilantaisaurus_ better as a megalosaur.  (I'm not even sure 
>if _C. tashuikoensis_ and _C. maortuensis_ belong to the same genus)


>Nick says:
>> Sinraptoridae [_Sinraptor_, _Yangchuanosaurus_, _Szechuanosaurus_,
>> _Metriacanthosaurus_, ?_Gasosaurus_/_Kaijiangosaurus_, and
>> ?_Marshosaurus_];
>Could _Szechuanosaurus_ be an allosaurid?

It depends on what taxon you're talking about :-)  Szechuanosaurus' type is
a tooth, there is a Shangshaximiaoan (Upper Jurassic) form that might be
sinraptorid, and a Xiashaximiaoan (Middle Jurassic) form that seems to be a
very primitive tetanurine (S. zigongensis).

>> and Carcharodontosauridae [_Acrocanthosaurus_, _Bahariasaurus_,
>> _Carcharodontosaurus_]).
>_Bahariasaurus_ and _Deltadromeus_ are probably basal coelurosaurs - 
>the paper by Paul Sereno (and his small army of co-authors) on 
>_Carcharodontosaurus_ established this quite well.  Their closest 
>relative may be _Dryptosaurus_.

A clarification: Sereno et omnia point out that the Deltadromeus
material previously considered "Bahariasaurus" does *not* include the
type material of Bahariasaurus ingens.  That is a different taxon
entirely, but what it is hasn't been dealt with.

Also, they identified "Spinosaurus B" as Carcharodontosaurus material.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661

"There are some who call me...  Tim."