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Re: Aucasaurus and the abelisaurs

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?
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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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