Giganotosaurus questions

[Joe Daniel <jdaniel@aristotle.net>]

First a big thanks for those of you who helped clear up my confusion on
the theropod classification.  Ya'll did such a good job I have some more
questions for you:)

I happened to stumble across the article in Nature (21 Sept 95)
announcing Giganotosaurus.  I may have been hallucinating but I thought
I remembered someone saying the forelimbs were more allasauroid in
proportion, from which I inferred they would be bigger than the
diminuitive arms on T. rex.  So I was a bit surprised to read that the
pectoral girdle was smaller proportionately on Giganotosaurus than for
T.rex and that the forelimbs themselves were not actually recovered. 
Was I hallucinating, or if not, anyone got any ideas on the bigger arms
on smaller pecs problem?

Also, the dentary seemed unusually massive in the picture.  I have
virtually no firsthand experience with giant theropod bones so I am may
be completely wrong about this.  How does it compare with tyrannosaurs?

Thanks,

Joe Daniel