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Re: Biggest predators
In a message dated 3/18/99 2:35:34 AM EST, firstname.lastname@example.org
<< I never saw them together to compare - but I agree - they must be different
genus - especially their skulls look quite different .
The eyes of Tyrannosaurs are more forward directed - obviously it had
better stereoscopic vision than Tarbosaurus.
Absolutely correct. Also, relatively longer, slenderer skull in Tarbosaurus,
with more maxillary and dentary teeth (e.g., dentary count 16 versus 13 in T.
rex) that are somewhat smaller and slenderer than the "rail spike" teeth of T.
rex, and skull much narrower behind, with occipital condyle visible in dorsal
view (so skull is held more horizontally than in T. rex; forwardly declined
skull is part of the stereo suite of characters of T. rex skull). In addition
to generally larger size (est total length 14 meters vs. 8-10 for
Tarbosaurus), Jenghizkhan has relatively taller dorsal vertebrae with the
tallest neural spines (though still pretty short when compared with something
like Acrocanthosaurus) in Tyrannosaurinae. All tarbosaurini (Tarbosaurus and
Maleevosaurus; unknown in Jenghizkhan) had relatively the smallest forelimbs
of all tyrannosaurines, probably a synapomorphy for the tribe.