Re:Questions about Abelisaurus

[jrw6f@faraday.clas.virginia.edu]

>  I'm trying to draw an "accurate" picture of Abelisaurus.  I have
>just about every popular book on dinosaurs, and they only give me
>limited info.  ><

Unfortunately, you can usually only get limited info, since most finds
are fragmentary.  The best thing to do is get the origional source.
The only thing I know is that it was published in 1985.  Anyone got
the Ref.?

>I'm just not buying that it should be restored with a Carnotaur-like
>body.
        While it is unfortunate that a full skeleton has not been
found, I'm afraid that Carnotaurus is the closest putative relative
that I have heard of.  Granted, it is fairly abberant.  If you are
really unwilling to use Carnotaurus parts, Iuess you *could* use
Ceratosaurus' spine and legs, and Carnotaurus' pelvis and modify the
forelimbs.
        The point stands, however, that any such representation would
be completely conjectural (Steve Cole, you still there?), and not in
completely scientific.

>My best guess is that it had more in commen with the [E]n-Vogue
>Charcharodontosaurus

        Never gonna get it, never gonna get it...
        Sereno's best guess is that Charcharodontosaurus is a
Allosaur, and I think I can aggree with him on that (haven't read the
paper yet, just from looking at it).

> Simply from a visual stand point, the skulls have a lot in commen.

Unfortunately, so do most large theropod skulls.  You have to look for
synapomorphies.

>Is there any thing else besides the post orbital fenestra (sp?) and
>the pinched orbit ( excuse the terminology, but you know, that
>Tyrannosaur like eye socket) that would cause one to think that it
>was related to a Carnotaurus?

If by "it", you mean Abelisaurus, well, I'm no expert, but as Tom
Holtz pointed out to me recently when asked the same question:
quadrate (the big bone at the back of the skull which you can barely
see from the side) tall, infra-temporal fenestra consequently high,
possibly no squamosal/quadratojugal contact, premaxillary high and
narrow anterio-posteriorly, invasion of post-orbital into orbit
(convergent with tyrannosaurs, some albertasaurs, Giganotosaurus, and
Acrocanthosaurus).  It is more than likely that at least a slight
reduction in the length of the radius+ulna is primitive for the group.
        Charcharodontosaurus (which is currently in my latest
datatset, flirting with being closely related to Shanshanosaurus
(which makes me wonder...)) does not seem to have any synapomorphies
with Abelisaurus except the orbital bar, and possibly the high
quadrate, although it's quadrate does seem more reminiscent of
Giganotosaurus.

>  Next question.  W[ere] there any other Pterosaurs living with BIG AL
>besides Ornithicherius or Nyctosaurus?

        Undoubtedly...  :)

Wagner

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! Jonathan R. Wagner                                               !   
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! jrw6f@virginia.edu                                                  !      
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!     http://faraday.clas.virginia.edu/~jrw6f       !      your mother is..."   
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