Re: STEGOSAUR TAILS (WAS DUCKBILL NECKS)

["Jaime A. Headden" <qilongia@yahoo.com>]

Brian Franczak wrote:

<Then, of course, there is the evidence of such ligamental contraction
in the tails of sauropods (the juvenile _Camarasaurus_ comes to mind),
_Struthiomimus_, _Compsognathus_, _Archaeopteryx_, and
_Sinosauropteryx_ (just to name a handful). In all these instances,
the tail does *not* articulate straight out from the pelvis, but is
pulled up in the same (if not quite as extreme) distorted manner as
the neck and skull. Looking at these examples, why would stegosaur
tails be straight and not similarly bent if that was what was
happening to them?>

  It's possible this is because of the neutral articulation of the
caudals, and the processes that lock them together (the pre- and
postzygapophyses, for instance). If these prevent the rigor mortis
from abbrogating the neutral position, then the tail is not going to
disarticulate to correllate to other dino's tails.

  Take *Caudipteryx* and *Archaeopteryx*, for examples. These have
only the mobile proximal vertebrae (the first 8-10 in Caudi) as being
anything but ram-rod strait. Dromaeosaur tails represent an extreme
case, but here I show you the example of a highly processed tail being
flexible along its length (best example, the "Fighting Dinosaur"'s"
*Velociraptor*).

  Question is, how close to the processes come to their alternates on
the preceeding or following vertebra. In Caudi and Archie, for
instance, these are so close to each other as to prevent _any_
flexion. Same for *Sinosauropteryx*, whose tail is inflexible for
nearly 3/4 its length.

  But I agree that post-mortem posing is not to be taken as the living
state.

==
Jaime A. Headden

Qilong, the website, at:
http://members.tripod.com/~Qilong/qilong.html
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All comments and criticisms are welcome!

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