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Sauropod neck positions: "High" is a relative term.



Dino-playmates,

Yesterday, I attended a talk by Dr. Michael Parish,
of the University of Northern Illinois, on the topic
of cyber-paleontology (computer reconstruction
of skeletal life positions).  He studied
the neck posture of Apatasaurus, Diplodocus, and
Barosaurus. Parish and his co-worker from
the U. Oregon meticulously measured the orientations
of all zygopophyses and all centrum facets on the
cervicals and put it all into a Silicon Graphics
Workstation.  To analyze the data, Parish's co-worker
(name escapes me; sorry to whoever you are) created a
3D-morphological dynamics analysis program that he has dubbed
"DinoMorph", written in C++.
Their results were surprising (at least to me; G. Paul
may yawn at the results!).

First, a term: "Neutral position" of the neck articulation
means the position where the zygopophyses are fully
overlapping each other.  All other positions are when
the zyg's are slid slightly off full contact.

Apatasaurus:  Couldn't get it's head up as high as previously
thought.
The neutral position for ALL the cervicals puts the
neck pointing toward the ground!  Because the occipital
condyle is sort of set at a 90 degree angle to the head
length, the head is tucked down relative to the neck
axis in the neutral position.
The neck/head was quite flexible in the ventral direction,
and the animal also had extremely good flexion side to side
(Parish showed an illustration of 180 degrees flexion side
to side).
The maximum vertical reach of the head above the ground
was only 5 meters (15 or so feet).

Diplodocus: Neutral position of entire complex: head also
points down almost to ground similar to Apatsaurus.
Very little side to side motion (compare to Apatasaurus above).
But even more ventral flexion that Apatasaurus.
Not so much flexion in the dorsal direction.

Barosaurus (work in progress): Quite stiff-necked animal.
BOTH vertical and lateral movements are limited.

Brachiosaurus: head was indeed held higher than other
sauropod families, but not as high as previously thought.
Neck was, compared to the above animals, more stiff,
and probably more straightly-held.


There was more, but as I am slow at scribbling notes,
this was all I was able to transcribe for you.
Any thoughts, comments, rebuttles?

That is all,

                <pb>

p.s. Oh, by the way, "Dinomorph" currently runs only
on the Silicon Graphics Workstation, but Parish's
co-worker is presently porting it over to the PC!


--
                 Phil Bigelow
                 bh162@scn.org