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RE: Tyrannosaurus was not a fat boy or girl



FYI for those following this dialogue, now that SVP 2011 is receding into
Deep Time we have submitted our reply to GS Paul's commentary on PLoS One,
viewable at:

http://bit.ly/tLq5Nv
(odd PLoS website formatting errors for italics are being corrected)

Cheers,
John


-----Original Message-----
From: John R. Hutchinson [mailto:jrhutch@rvc.ac.uk] 
Sent: 23 October 2011 08:27
To: dinosaur@usc.edu
Subject: RE: Tyrannosaurus was not a fat boy or girl

We'll be responding in due time of course. 

What is good for the goose is good for the gander/tyrannosaur- one should
wonder how accurate and reliable are scale model-based estimates, or how
accurate and reliable are classical anatomical methods for estimating speed?
How accurately can one make a scale physical model of a skeleton and how
accurately do they add flesh to it? How reproducible are those methods and
how much investigator bias is there? And what effort has been put into
testing those methods as applied to tyrannosaurs? Don't look behind the
curtain, folks. Don't read the literature and compare the effort put into
testing different methods. :)

Anyway, there is the scientific approach where one tries to test hypotheses
with available evidence (and addresses the unknown factors involved, if
doing good science), anti-scientific nihilism, or giving up and just not
trying (the latter two can be hard to tell apart). I prefer the former. We
should all give up on paleontology if we need time machines to do science...
or art.

The growth plot follows the published Erickson et al. DME methods (cited and
in refs), which one can read to understand. As others have already noted,
the approach is best at estimating growth during the period represented by
data, which is what we focused on in the paper, because we like using data
(but the curve makes estimates beyond those). Once we have <10yr old
Tyrannosaurus rex, we can address what happened at younger ages, although it
is almost certain not to be where the "growth spurt" happened, so I don't
know what the important question would be.

Tyrannosaurily yours,
John


-----Original Message-----
From: GSP1954@aol.com [mailto:GSP1954@aol.com] 
Sent: 22 October 2011 23:26
To: dinosaur@usc.edu
Subject: Tyrannosaurus was not a fat boy or girl

I've placed a comment with the Hutchinson et al. PLoS One paper on 
Tyrannosaurus masses. 

Enjoy. 

It is becoming apparent that the uncertainties is restoring the power 
dynamics of extinct animals are so extensive that it is not possible to
calculate 
whether or not adult Tyrannosaurus were slower or as fast than the 
obviously fast juveniles. If someone eventually comes up with power
calculations 
estimating that an adult Tyrannosaurus could run 30-35 mph I will be happy
but 
not sure how it is more reliable than those estimating only 20-25 mph. We 
are going to have to wait until time machines are available. I shall get to 
work on that. 

Also do not quite get the plot in Fig 6 in the Hutchinson et al. paper. It 
seems to show 10 yr old Tyrannosaurus not weighing anything. Odd. 

GSPaul</HTML>