Re: large Argentine specimens

[rowe@lepomis.psych.upenn.edu (Mickey Rowe)]

Stan responds to me:

>Rather, implications about *sauropod* metabolism.  There is no real
>reason to presume that all dinosaurs had the same style of metabolism.

I hope I didn't leave people with the impression that I presumed as
much.  Certainly Peter (Dodson) doesn't make that mistake.  However,
as I understand Peter, he thinks his calculations show that there's a
pretty strong cutoff -- a mass above which a tachykinetic metabolism
is completely untenable.  I don't remember the exact number, but I
think it's somewhere around the size range of a large hadrosaur.

Another argument (attributed to Jim Farlow in the _Science_ paper that
started this discussion) is that if a Sue-sized theropod had to
maintain a high metabolism, its population density would have to be so
small as to make the species a strong candidate for extinction via
random events.  To put it in the terms used by David Raup in
_Extinction Bad Genes or Bad Luck_, they would have existed close to
the absorbing boundary at zero population size.

In any case, the large sizes attained by these animals can lead to
strong arguments about the metabolism of these particular creatures.
Nothing more, nothing less.

-- 
Mickey Rowe     (rowe@lepomis.psych.upenn.edu)