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New Rigby Giant



Brian Franczak wrote:
> 
> For those who might not have seen it, the latest issue of EARTHWATCH
> magazine (November/December 1997) has a small article on Keith Rigby's
> Montana dig. The site contains remains of hadrosaurs (possibly
> _Edmontosaurus_ and _Parasaurolophus_), a large theropod
> (?_Albertosaurus_), small theropods (?_Dromaeosaurus_ and an even smaller
> "sickle-claw"), and that really honkin' big tyrannosaur (which they seem
> reluctant to identify as _T. rex_; to which I have to ask, what else WOULD
> it be? Could there BE another theropod in the Late Cretaceous THAT BIG that
> we've never found any evidence for yet?). The pubis of the tyrannosaur
> (there's a really cool photo of Rigby with a tape measure to the thing)
> measures 133 cm. According to Rigby, the longest measured _T. rex_ pubis is
> 123 cm. The article states that the skull of the animal "measures fully two
> meters long." Rigby says, "I knew we had something big when we found... the
> pubis. It is *huge*. If the scaling works, this animal may be 15 percent
> larger than the largest _T. rex_ on record."
> 
> Yowzah!
> 
> Brian (franczak@ntplx.net)
Brian, and all, do you know how reliable this figure ( skull fully two
meters) is? If it is this is truly one gigantic tyrannosaur.The largest
skulls of any land animals (_Triceratops_ and _Torosaurus_) attain
lengths of 7.5 feet if I remember right. In comparison, imagining a rex
skull even close in overall length is awe inspiring.The ceratopids
benefit from an elongate "frill' which in _Torosaurus_ accounts for much
of the size.The rex, with it's deep blunt snout and proportions would
certainly be a competitor in the "largest land animal skull" department
if judged by sheer volume.Also....I'll second Brian's question on
Rigby's reluctance at indentifying the genus/species as _Tyrannosaurus
rex_.To my knowledge, there is a large diversity of size and shape in
individual skeletal elements among rex. The result of changing gene
pools within a species, that we are veiwing in a few individuals from
different areas across a wide spectrum of that species' time on Earth?
What bones is he seeing a difference so drastic that it would cast doubt
on the species falling within rex? And what do the resident tyrannosaur
specialists (Holtz?,Paul,etc.) say about the variation of skeletal
features within _Tyrannosaurus rex_? How large a variation ( in your
opinions), and in what skeletal features, should we see before we
construct a new species within Tyrannosaurus or a new genus
altogether?----Just thinking again, Sean C. :-D