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Re: Rex jaws
At 01:26 PM 6/4/99 -0400, Patrick Norton wrote:
>_T. rex_ (and most toothed theropods, for that matter) had a "wrap-around
>overbite": the whole upper surface of the lower jaw fits within the
>of the lower jaw. <
>That arrangement may have allowed the animal to simply break long bones
>by chomping on them rather than cutting or gnawing them as do mammalian
>carnivores with occlusal teeth.
Although it may have *allowed* robust-toothed tyrannosaurs like _T. rex_ to
do some long bone chomping, the wrap-around overbite of theropods is a very
primitive feature, going way back to early archosauriforms.
In these animals, and indeed in the majority of toothed theropods, the teeth
are narrow and ziphodont (blade-like), the skull is hatchet-shaped, and
there is no ossified secondary palate. In these forms bone-crunching is
unlikely to have been a major aspect of their feeding: their skulls and
teeth would not be well able to absorb the non-vertical forces exerted by
Most of these animals probably didn't do much in the way of bone munching,
but stuck with the flesh, viscera, etc.
Thomas R. Holtz, Jr.
Vertebrate Paleontologist Webpage: http://www.geol.umd.edu
Dept. of Geology Email:firstname.lastname@example.org
University of Maryland Phone:301-405-4084
College Park, MD 20742 Fax: 301-314-9661