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Re: Tyrannosaurid neck muscles and feeding style

*Leaps onto bandwagon*

I'd love to nab a copy as well.



--- Guy Leahy <xrciseguy@sbcglobal.net> wrote:

> Anat Rec (Hoboken). 2007 Aug;290(8):934-57. Links
> Functional variation of neck muscles and their
> relation to feeding style in Tyrannosauridae and
> other
> large theropod dinosaurs.Snively E, Russell AP.
> Department of Biological Sciences, University of
> Calgary, Calgary, Alberta, Canada.
> Reconstructed neck muscles of large theropod
> dinosaurs
> suggest influences on feeding style that paralleled
> variation in skull mechanics. In all examined
> theropods, the head dorsiflexor m.
> transversospinalis
> capitis probably filled in the posterior dorsal
> concavity of the neck, for a more crocodilian- than
> avian-like profile in this region. The
> tyrannosaurine
> tyrannosaurids Daspletosaurus and Tyrannosaurus had
> relatively larger moment arms for lateroflexion by
> m.
> longissimus capitis superficialis and m. complexus
> than albertosaurine tyrannosaurids, and longer
> dorsiflexive moment arms for m. complexus. Areas of
> dorsiflexor origination are significantly larger
> relative to neck length in adult Tyrannosaurus rex
> than in other tyrannosaurids, suggesting relatively
> large muscle cross-sections and forces.
> Tyrannosaurids
> were not particularly specialized for neck
> ventroflexion. In contrast, the hypothesis that
> Allosaurus co-opted m. longissimus capitis
> superficialis for ventroflexion is strongly
> corroborated. Ceratosaurus had robust insertions for
> the ventroflexors m. longissimus capitis profundus
> and
> m. rectus capitis ventralis. Neck muscle morphology
> is
> consistent with puncture-and-pull and powerful shake
> feeding in tyrannosaurids, relatively rapid strikes
> in
> Allosaurus and Ceratosaurus, and ventroflexive
> augmentation of weaker jaw muscle forces in the
> nontyrannosaurids.

"I am impressed by the fact that we know less about many modern [reptile] types 
than we do of many fossil groups." - Alfred S. Romer

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