Re: Aucasaurus and the abelisaurs

["Oliver Rauhut" <owmrauhut@hotmail.com>]

Facial contraction in Carnotaurus (and in Mahungatholus) is most probably a 
predatory adaptation. A short skull, in combination with large temporal 
openings and reinforced nasals and frontals indicate a poweful bite (in 
contrast to what was published in GAIA, but see the article by Molnar on the 
skull mechanics of Tyrannosaurus), since it reinforces the skull roof and 
sides against vertical forces (?impact forces) while at the same time 
reducing the leverage of the anteriormost bite point (which, given the 
proposed hunting strategies,  in theropods might have played a more 
important role than the posteriormost bite point). However, don't ask me how 
the apparently weakly constructed intramandible joint in Carnotaurus fits 
with this... (However, keep in mind that bony connections are not 
everything. Connective tissues, especially tendons, can give considerable 
stability to structures that look weak or even hyperkinetik from the 
osteology alone).
As for the arms of Carnotaurus, I am at a loss for a plausible explanation. 
The complex anatomy of these arms indicate that they had some use other than 
pure species recognition (or similar things), but what that was, I don't 
know...

Oliver Rauhut


> From: "ekaterina amalitzkaya" <eamalitz@hotmail.com>
> Reply-To: eamalitz@hotmail.com
> To: dinosaur@usc.edu
> Subject: Aucasaurus and the abelisaurs
> Date: Wed, 27 Jun 2001 04:16:56 -0000
>
> With the preliminary reports that Aucasaurus is a more regular abelisaurs
> with a longer skull and arms, is it true that only Carnotaurus appears to
> have those highly aberrant features: The degradation of the Fore arms and
> the facial contraction. Would you all have any explanation for the 
> teleology
> of these apparently maladaptive traits for a carnivorous theropod. Sexual
> selection is a straight forward excuse but is there anything else that
> appears suggestive?
> thanks
> EA
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______________________________
Dr. Oliver Rauhut
Museo Paleontólogico Egidio Feruglio
Fontana y Lewis Jones
9100 Trelew
Chubut, Argentina
Tel: 0054 / 2965 / 420012
Fax: 0054 / 2965 / 432100
email: owmrauhut@hotmail.com

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