Re: Ornithischia/Saurischia Ilium Mass Distribution Hypothesis

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

Mike Milbocker (mmilbocker@psdllc.com) wrote:

<Formal Hypothesis: For any ilium of the Dinosauria, find the line L for
which the moment of inertia is a minimum; find the point H on the line L
which is the most cephalo for which a plane perpendicular to L and
containing H intersects a point on the ilium; find the point T on line L
which is the most caudal for which a plane perpendicular to L and
containing T intersects a point on the ilium. Now, find the point M
equidistant from H and T on L. A plane drawn through M and perpendicular
to L divides the ilium into 2 regions. If the mass of the cephalo region
is greater than the mass of the caudal region, the ilium is Saurischian,
otherwise it is Ornithischian.>

  While acknowledging that this is a very neat theory, that one can
determine ornithischian from saurischian pelves under such criteria,
and/or that one can determine that such mass distribution is indicative of
which group an ilium falls under, one should have a few test ilia that
provide such a sound statement. As in, one can determine that the ilium of
*Alxasaurus* is saurischian (it is) despite it's arrangement of elements
resembles that of several ornithischians as well as advanced sauropods.

  Where precisely on these primitive theropod ilia is the moment of
minimum inertia? And pardon me for my dunce-itude for asking such a
question, but I am curious as to the method by which one arrives at this
point with only ilia.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


        
                
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