Re: Giganotosaurus Arms Vs. T-Rex Arms

["Scott Hartman" <scott_hartman@hotmail.com>]

> > > Giganotosaurus does have smaller arms , bulk wise.
T. rex arms were around the same LENGTH as an adult human .There the size 
similarity ends.The bulk makes the difference . I've not seen any
references that would indicate that Giganotosaurus had "beefy" arms . T.rex, 
on the other hand (no pun intended) ,supposedly could heft about 400 lbs 
with one arm .<<<

   You know, I can't tell you how often I run into this misperception.  
Yes, T.rex could probably curl around 400 lbs.  I'm hardly a trained 
athlete, and I can curl at least 40 lbs.  That's 1/4 my body weight.  By the 
same token an animal the size of a T. rex should be able to curl at least a 
ton.  "Oh, but the arms are incredibly massive for their size!" could be the 
response, but I'm not sure what use that is without taking body mass into 
account.  After all, Mononykus' forearms are far more robust (and apparently 
better muscled, looking at the biceps tubercle, not to mentionthe olecranon 
from which it derives its species name) for "their size" than a 
tyrannosaur's, but there is little popular mention of it.
    The reason I mention all this is because some of the muscles associated 
with the forearm, especially the latisimus dorsi and the pectoralis, also 
make importqant contributions to the structural integrity of the rib cage.  
So T. rex didn't neccessarily have strong arms because they were used for 
anything, but rather some of the muscle attachments appear large becaue 
those muscles are still important to a 6 ton animal.
   As for Giganotosaurus, according to Nate Murphy, who worked on the 
excavations with Phil Currie has mentioned that they are more robust than a 
tyrannosaurs.  I can't confirm or deny that statement.  Sorry.

Scott
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