[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Parrish's neck work ...



Matthew Bonnan wrote:

<The assumption is that a large nuchal ligament ran
off the sacral region, across the back, and inserted
itself on the neck or back of the skull. If you're
unfamiliar with what a nuchal ligament is, it is a
rubber-band like tissue which in mammals runs from the
shoulder vertebrae to the back of the skull. It is a
passive tissue. That is, like a rubber band, it can
only store energy and release it, but it cannot
generate energy on its own.>

[snip]

<How a passive tissue could generate enough energy to
lift the entire front end of a sauropod off the ground
has never been investigated. There is a lot of
speculation on how or why it might work, but so far
there have been no quantitative models or studies of
this. Why else would you have tall neural spines over
the sacrum?>

  This would be easily explained if the muscles of the
neck were brought into question. Sauropods like the
"euhelopodids" and neosauropodans (brachios, titanos,
diplos, apatos) had enormously sized scapulae,
probably for the express purpose of supporting the
trapezoideus and related neck muscles, to support the
neck. Now, granted, the biggest scapulae to back
muscles belong to sauropods like *Brachiosaurus* and
*Euhelopus,* exceptional with upright or semi-upright
necks, but this accentuates my point.

[snip]

<The elongate heads with their pencil-like teeth are
very weird. These animals did not chew, but swallowed
whatever they ate whole, because unlike mammals, they
have no molars, no canines, etc. It's as if your mouth
were filled entirely with pencil-thin incisors. The
best you could manage would be to snip off things and
swallow them. These teeth don't instantly strike
someone as being able to handle tough, woody foods or
even some of the tougher piney plants. Again, even if
the sauropods get their heads up in those trees, how
they were used and what food was available for them to
break off and swallow is difficult to know.>

  *Antarctosaurus wichmanianus* had a very squared off
jaw, and perhaps perfectly exapted to graze with, as
is seen in grazing animals like the black rhinoceros
as opposed to the white rhinoceros, whose snout is
more pointed. *Diplodocus* has a more rounded front
end of the snout, and the tooth pattern looks like a
cookie cutter formed of an arc of a third of a circle,
with a single, flawless, corrugated edge; the lower
set occlude inside the upper set, perfect for chomping
with. *Apatosaurus* was more pointed, and narrower
relatively, but formed a semi-circle. Adaptations in
specific feeding styles, and food, probably, as Krause
et al. have proposed for the Mahajanga titanosaurs,
and as is seen in other titanosaurs, the later
compared to the earlier.

  End comments.

===
- Greek proverb: "Knowledge is Inherent;
  Stupidity is Learned." -

Jaime A. Headden

Qilong, the we---is temporarily out of service.
Please check back when the phone lines are not busy.
_________________________________________________________
Do You Yahoo!?
Get your free @yahoo.com address at http://mail.yahoo.com