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Re: Spinosaur Variation (with new question)



>  Speaking of theropod bite actions, and about
>spinosaurs snapping their heads sidewise like crocs
>(who have laterally broad jaws)

Ummm...  Not all crocs have laterally broad jaws.  Sure, _Crocodylus_ has
relatively broad jaws, and _Alligator_ and the caimans very broad jaws, but
_Tomistoma_ and _Gavialis_ have exceedingly narrow jaws.

>and spinosaurs being
>relatively weak in that department: Is it more likely
>then that the jaws were equated with backward ripping
>devices,

Since their teeth are cones, they would make very poor ripping devices
(relatively to typical theropod ziphodont teeth).

>due to the angle of the premaxillary teeth,
>the fit of the lower jaw to the upper in front, and
>the radial arrangement of the anterior lower teeth?
>This goes out to all, by the way.

Most people who've looked at the tooth rossette of the end of the snout have
likened it to a pincher: pierce & hold.

Furthermore, I've always envisioned spinosaurs as more of vertical strikers,
like fish-eating wading birds.  The resistance to torsion would aid not so
much in the spinosaur thrasing its own head about, but in absorbing the
forces generated by struggling prey.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:tholtz@geol.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661