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Re: Sue's head, cartilage, and whatnot...(kinda long)



Amendment:  "or, more likely that once the
> cartilage dehydrates post-mortem, the intervertebral gaps will 'shrink' -
it . . . "

SHOULD read:  or, more likely that once the cartilage dehydrates post-mortem
[and then decays entirely, prior to the fossilisation process], the
intervertebral gaps will 'shrink' - it . . .

Makes the statement a little more intelligible

Muttley


----- Original Message -----
From: "Muttley" <drinker@alphalink.com.au>
To: <DinoBoyGraphics@aol.com>; <dinosaur@usc.edu>
Sent: Monday, November 03, 2003 6:57 PM
Subject: Re: Sue's head, cartilage, and whatnot...(kinda long)


> Just a small observation from one who once taught anatomy and physiology
for
> a living; be aware in your discussions that cartilage dries out to a very
> dramatic degree post-mortem. Thus, any cartilaginous "tissue" which
> fossilises is going to appear much thinner than it would in life - (ie the
> so-called "mummified" fossil material) or, more likely that once the
> cartilage dehydrates post-mortem, the intervertebral gaps will 'shrink' -
it
> is this shrinking (or stenotic response) between vertebra and at articular
> interfaces along with the post-mortem tightening through rigormortis and
> dehydration of tendonal tissue which causes the arched neck position of
many
> finds which once led to the theory that the dinosaurs died from toxic
> influence and died in convulsive agony.
>
> I think the 10% figure is getting closer to the true figure and will
> ultimately rnder a more complete and 'truer' rendition of a diagrammatic
> reconstruction.
>
> Muttley
>
>
> ----- Original Message -----
> From: <DinoBoyGraphics@aol.com>
> To: <dinosaur@usc.edu>
> Sent: Monday, November 03, 2003 9:24 AM
> Subject: Sue's head, cartilage, and whatnot...(kinda long)
>
>
> > Just to respond to a few good points brought up:
> >
> > Jon, aka Trouble Stirrer:  You maybe right about the room for the
> cartilage between the vertebrae:  10% is a value commonly given, but the
> amount is variable.  I got to play witha  cast of "Stan" this summer, and
I
> suspect something closer to 5% is accurate, which may be consistent with
the
> stiff-ish backs fo coleurosaurs (or at least tyrannosaurs).  As for the
> limbs, I don't believe in the dogmatic "dinosaurs had thick
cartilageouness
> joints" bit.  I don't think they would have had substantially thicker
joint
> cartilage than mammals (e.g. a thin veneer of hyline cartilage).  On the
> other hand, if "Sue" really is a subadult (what would be up with that?!),
> then I am wrong and there probably should be more limb-joiint cartilage.
> Pick your favorite excuse ;)
> >
> > David brought up the cartilaginous episternum which is drawn but may not
> have been present.  Although I think there are good phylogenetic reasons
to
> infer such a structure, you will kindly notice that I did not draw it on
the
> rigerous detail of Sue and what is known of "her."  So the viewer is left
to
> decide whether to believe me or not in my assumption.
> >
> > And finally, Mr. Varner (thanks for the frequent art-related notices, by
> the way Dan!) asked about restoring squashed skulls.  Actually, I think he
> was asking Jon, but since I'm the culprite in this case, I thought I'd
chime
> in anyhow.  In the case of FMNH PR2081 the situation isn't quite as bad as
> it appears.  The jugal, squamosal, quadratojugal, and postorbital are more
> disarticulated than deformed, so it isn't too difficult.  The nasals are
> squashed all to heck, but the premax isnt, so with a little tlc inr
estoring
> he lacrimal (which isn't too squished, anyhow), ant the premax/lacrimal
> positions nicely constrain the nasals and the dosral extent of the
maxilla.
> >
> > I'm not sure that the "differences" warant generic seperation yet,
because
> I'm not convinced that the AMNH skull isn't different in large part due to
> it's own distortion.  But then again, maybe there are two species of
> tyrannosaur running around the maastrichtian of N.A.
> >
> > All the best,
> >
> > Scott
> >
> >
> > Scott Hartman
> > Zoology & Physiology
> > University of Wyoming
> > Laramie, WY 82070
> >
> > (307) 742-3799
> >
>