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Rahul Daryanani writes:
 >> What calculations have you done?
 > 
 > Actually, Mickey Mortimer did these.
 > 
 > http://dml.cmnh.org/2001Sep/msg00402.html
 > http://dml.cmnh.org/2001Jun/msg00665.html.

I'm familiar with Mickey's length-and-mass calculations.  My question
was, assuming that Mickey's very tentative figures are correct, what
calculations make you think that animals this big are impossible?  Or
is it just a feeling you have?

 >> The _only_ published work on this think remains the original
 >> atrocious description.
 > 
 > I've heard rumors that the original description and illustrations
 > were bad, but I didn't realize it was that pathetic.

Well, you can see the figure from the paper here:
http://www.miketaylor.org.uk/tmp/bruhathkayosaurus/Bruhathkayosaurus.jpg
(courtesy of Mickey).  I think you'll agree that to describe this as
"pathetic" is being kind.

 > If it was really that bad, how did Mortimer get such precise
 > estimates.

He didn't!  Mickey's estimates (A) explicitly encompass a range of
25%, and (B) are very very uncertain anyway, being based on the length
of ONE BONE -- a none that has NEVER been described in print as being
part of a sauropod, and that may be a tree-trunk.  Really, you're
trying to find precision where none exists.  You just have to accept
it.

 > When I did similar calculations with comparisons with Brachiosaurus
 > and other, more well known dinosaurs, I got very rough estimates.

And so you should!  Remember that _published_ estimates of
_Brachiosaurus_ mass include 78 tonnes (Colbert 1962), 15 tonnes
(Russell et al. 1980), 47 tonnes (Alexander 1989), 29 tonnes (Anderson
et al. 1985), 180 tonnes (for "Ultrasauros") (Norman 1988), 32 tonnes
(Paul 1988), 74 tonnes (Gunga et al. 1995), 37 tonnes (Christiansen
1997) and 26 tonnes (Henderson 2003).  Since that encompasses a factor
of twelve, we really do need to be circumspect when it comes to trying
to give precise masses.

(Now to be fair, some of those estimates, including the highest and
lowest are complete nonsense.  But, still: reasonable, modern and
rigorous estimates for the mass of the very same _B. brancai_ specimen
still range between 26 and 37 tonnes (Henderson 2003 and Christiansen
1997 respectively), estimates which differ by a factor of 42%.  And
remember, this is for one of the best-represented of all sauropods!

The moral: beware!  Beware!

 _/|_    ___________________________________________________________________
/o ) \/  Mike Taylor    <mike@indexdata.com>    http://www.miketaylor.org.uk
)_v__/\  "Any fool can write code that a computer can understand.
         Good programmers write code that humans can understand" --
         Martin Fowler, _Refactoring_.