RE: Sue Photos Online (Good ones!)

["Jerry D. Harris" <dinogami@hotmail.com>]

> there's only so much you can do with a
> fossil or cast without adding to the restoration.  The quadrates were
> splayed quite a bit in the actual skull, and it would have taken
> considerable breakage to fix all of it...This is also why the ribs >aren't 
> swept all the way back, as an earlier
> commentator observed.  This was not an oversight on our part - the rib
> heads and vertebral transverse processes are all distorted.  Had we
> articulated the ribs perfectly, the trunk would have been twisted to >the 
> left...Remember, when mounting real bones, one has to deal with >postmortem 
> distortion.  We wanted to minimize restoration on the bones >- restoration 
> covers up what's actually there, and we wanted to keep the bones as 
> pristine as possible for future researchers.

  This, of course, brings up the old mutual exclusivity of mounting real 
vs. cast bones.  Casts, if made properly, can undergo a sort of 
"antidiagenesis," in which diagenetic distortions are undone via the plastic 
properties of the casting material.  Mounts certainly look much, much nicer 
when distortions are corrected for -- it's more of that "the animal just 
died yesterday" sort of mount, like one would expect in a mounted skeleton 
of an extant animal.  I personally prefer these mounts.  However, mounting 
real bones shows the public what kinds of ravages time and physics imposes 
on fossils and, although never pointed out directly, implies to them what 
paleontologists have to go through to mentally undistort bones to properly 
interpret them (as we've seen here with the discussions about the skull 
shape in "Sue").  The mounts aren't nearly as pretty, but are more "real" in 
that sense.  Although I've not seen it done, it would be nice with said 
mounts if signage were put with the mount explaining why it looks lopsided, 
why the ribs aren't quite right, etc., and then have pictures of what the 
proper, restored bones _would_ look like.

  Also, the public, in my experience, frequently just assumes -- and 
probably expects -- that _all_ mounts are 100% real bone, even when they're 
actually casts (undistorted or not).  Given this, I'm not much for mounting 
real bone, or, alternatively, mounting casts (which are easier to mount, 
anyway) and then putting the real bones beneath the mount so both can be 
viewed -- it's easier for scientists to study them this way, too.  I have, 
however, done it both ways.  I am somewhat curious as to how much it was 
debated at the FMNH to mount real vs. casts of "Sue," and what the deciding 
factors were....?

  Just my $0.02...

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                     Jerry D. Harris
                 Fossil Preparation Lab
          New Mexico Museum of Natural History
                   1801 Mountain Rd NW
               Albuquerque  NM  87104-1375
                 Phone:  (505) 841-2809
                  Fax: ; (505) 841-2808
           >>>>> dinogami@hotmail.com <<<<<

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