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Spines (Re: Texas dinos)



> Acrocanthosaurus is more closely related to
> Allosaurus than to Spinosaurus.
> Unless Rauhut (2000) is right in saying the
> vertebrae of Spinosaurus belong
> to an allosauroid, and only the jaws belong to what
> we call a "spinosaurid".
> In that case, it's uncertain, but Rauhut's
> hypothesis has not been generally
> accepted.  Even if Rauhut's right, Acrocanthosaurus
> wouldn't be a
> "spinosaurid", which is probably the intent of your
> question.
> 
> Mickey Mortimer

I find Rauhut's theory to be fallacious. Stromer 1915
attributes the remains of a large theropod found near
a hill to one individual. Mike was the first to share
this with me, however, I think, morphogically, spines
over six feet in height could not work on such large
theropods as are carcharodontosauroids (especiallly
such laterally compressed neural spines). Aside from
that, Stromer figured the spines and the centra for
Spinosaurus which show an almost circular centra
rather than an ovalish one like the one in
_Carcharodontosaurus_. (I think the fact that the
neural spine and the centra are not fused (as shown in
the figs.) suggest this individual was not fully
mature.

Regarding the relationship of _Acrocanthosaurus_ to
_Carcharodontosaurus_, Currie and carpenter 2000
suggest that it (Acro) fits into Allosauridae and not
in Carcharodontosauridae. Contra Currie,
Acrocanthosaurus is united to Carcharodontosaurus by
such features as the prominent postorbital, the
tapering jugal+quadratojugal as well as squamosal. (to
name a few)
I hope this makes sense.

Stegosaurically,
-marco

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