Re: carcharodontosaur affinities

["Jerry D. Harris" <dinogami@hotmail.com>]

> Is Acrocanthosaurus considered a carcharodontosaur?  In sereno's trees they
> appear to group together.

  And in mine, too...

> Though the support for this grouping is really
> weak.

  Yes, but this is because neither _Carcharodontosaurus_ nor 
_Giganotosaurus_ have been fully described yet, so only the preliminarily 
published details can be plugged into data matrices. Certainly all three 
forms _are_ related, because the character support for them all being 
allosauroids is pretty good (though, last I heard, Coria and Salgado had 
some idea that _Giganotosaurus_ may acutally be an abelisauroid); the 
question is whether or not they are closer to each other than to 
_Allosaurus_.

> With his same matrix there are a few trees nearly as good where it
> groups with the allosaur+sinraptor clade and otherwise outside them in the
> neotetanurans.

  Uh, maybe it's just the early hour, but this sentence doesn't make sense 
-- if _Acrocanthosaurus_ groups _with_ (_Allosaurus_ + Sinraptoridae), then 
how can it fall outside that group, too?

> I remember Currie writing that he had found several unscored
> characters of the braincase that if included suggests and evolutionary link
> with the sinraptor clade. But is there not a paleogeographical problem with
> this linkage?

 Maybe; it depends on whether you believe some of the very fragmentary 
British Jurassic material is sinraptorid or not.

> What are the current opinions of the advanced students of theropods in this
> matter- is there a consensus?

  The consensus is that everyone wishes better material, and more complete 
descriptions, of _Carcharodontosaurus_ and _Giganotosaurus_ is needed before 
the matter can be put to some degree of rest.  ;-D

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                     Jerry D. Harris
                 Fossil Preparation Lab
          New Mexico Museum of Natural History
                   1801 Mountain Rd NW
               Albuquerque  NM  87104-1375
                 Phone:  (505) 841-2809
                  Fax: ; (505) 841-2808
           >>>>> dinogami@hotmail.com <<<<<

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