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RE: _Giganoto_ is no speedster (was RE: T rex brooding)
From: Thomas R. Holtz, Jr. [SMTP:firstname.lastname@example.org]
Sent: Friday, August 21, 1998 7:38 AM
Subject: _Giganoto_ is no speedster (was RE: T rex brooding)
At 08:49 PM 8/20/98 -0700, Jamie wrote:
><The estimates I have read and/or heard is that the Giganotosaurus
>longer & perhaps heavier than a Tyrannosaurus Rex, but not as tall
>muscular. Does that match the Mount in Philadelphia?>
> Longer, perhaps. Longer skull, definately. Taller, perhaps, but
>muscular? Perhaps not. *Tyrannosaurus* definatelty had a stronger,
>more bulky neck, even thighs and tail, while *Giganotosaurus* was a
>slender, speedier fellow.
Speedier? Not likely!!
_Gig._ has very robust, short, stocky legs whose proportions track
allometrically with other typical theropods (most ceratosaurs, basal
tetanurines, carnosaurs, and most coelurosaurs).
_Tyrannosaurus_ has long, slender legs whose proportions track with
ornithomimosaurs, troodontids, caenagnathids, etc. On top of that,
have a certain unusual adaptation of the metatarsus, which some
morphometric and biomechanical work (me, 1995, JVP 14:480-519) seems
indicate is related to enhanced cursorial ability.
Also, in _Tyrannosaurus_ (as in coelurosaurs in general), the
probably terminates closer to the pelvis than in more primitive
so the anterior portion of the tail might have been "bulkier" than
_Giganotosaurus_, but the posterior part of the tail would probably
slender (less muscled).
[As an aside for artists and others: PLEASE be VERY VERY cautious
restoring proportions of the limbs and tail in _Tyrannosaurus rex_.
AMNH mount and those derived from it (such as the ANSP mount) have
major errors: the legs are from a larger, more robust individual
rest of the skeleton, the foot is restored far to short and far to
(and lacking the true structure of tyrannosaurid feet), the tail of
mount still uses _Allosaurus_ based vertebral and chevron "falsies"
perfectly good examples of real tyrannosaurid caudals and chevron
are to be
found on the _Gorgosaurus_ models on the wall), etc.]
>A slash & run attacker, unlike the Super Rex
>(or at least, I presume not).
I seriously doubt running is much of an option for _Gig._, relative
On the matter of slashing, however, I agree most whole heartedly, as
discuss in a lot more detail at SVP this year (the title of my talk
"LARGE THEROPOD COMPARATIVE CRANIAL FUNCTION: A NEW "TWIST" FOR
Thomas R. Holtz, Jr.
Vertebrate Paleontologist Webpage: http://www.geol.umd.edu
Dept. of Geology Email:email@example.com
University of Maryland Phone:301-405-4084
College Park, MD 20742 Fax: 301-314-9661
That's pretty much the impression of Giganotosaurus I had from the
articles on this dinosaur. Just from the physics of the design,
Tyrannosaurus Rex seems been better adapted for running. Could
Giganotosaurus have been primarily an ambusher of prey? It also seems that
from the descriptions I have read that the Giganotosaurus skull (while
indeed LONGER than the Tyrannosaurus skull), may not have been as
biomechanically powerful. Is this correct?