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RE: Prehistoric Times (Tanystropheus, rigor mortis)




-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
Silvio Renesto
Sent: Thursday, October 17, 2002 3:17 AM
To: dinosaur@usc.edu
Subject: Re: Prehistoric Times (Tanystropheus, rigor mortis)



Please be so patient and let me add my last (at least for today) toughts on
this:

Without dismissing other possibilities I would recall that surely ligament
contraction in dead animals  occurs mainly in drier areas, but rigor mortis
(RM), i. e. contraction of *muscles* after death, may take place in water
as well as on land. RM happens (recalling to memory good old teachings of
anatomy)  because death stops production of ATP which is (VERY ROUGHLY
SPEAKING) responsable of muscle de-contraction by pushing off Calcium ions
from muscle protein (? tropomyosine ?) receptors.
When there is no more ATP, nothing pushes off the Calcium and muscles stay
contracted. RM normally does not produce odd,  too contorted postures if
the antagonist muscles are balanced, because all become contracted .
However if  epaxial muscles were more developed,  bigger etc. than hypaxial
ones, it is feasible that they may induce some deformation in posture with
their contraction.
If the epaxial muscles in the neck of Tanystropheus were more developed
than hypaxial ones, since these latter may have been in part replaced by
the  rib "bundles"- that can't contract-, this may explain why we found all
these advanced prolacertiforms  (i. e. Tany., Macrocnemus,
Langobardisaurus, Cosesaurus and, correct me if I'm wrong,
Tanytrachelos)  with the neck sharply bent or even curled backwards.
Does it sound feasible to you?

Cheers
                                                 Silvio Renesto<<

Ok, I'll buy that. Sounds good to me.




Tracy L. Ford
P. O. Box 1171
Poway Ca  92074