Overall, as David said a very interesting and enlightening rant. Guess
we can scrap DinoMorph's conclusions for the most part.
who's "we"? And why couple the two methodologies (2D digital photo-
compositing and 3D modeling)? And why "scrap conclusions" regarding
the scientific utility of reconstructing osteological neutral poses
(see specifics below)?
1) Some published silhouette drawings, while dimensionally accurate
as far as major dimensions such has overall bone lengths, are
morphologically inaccurate, simplified, or idealized. This is a
matter that can be verified, and should not be caught up in endless
arguments and rants.
2) We have just learned that, for one artist at least, the lateral
view depictions of the body plan are NOT necessarily intended to show
osteological neutral pose (ONP) along the axial skeleton. Instead,
they are constrained only to showing some osteologically-achievable
posture. I have only created 2D digital photo-composites of the
axial skeleton in the osteological neutral pose (ONP). That I
believe, and I expect most others believe, is unbiased starting point
for attempting to reconstruct an overall bauplan and to subsequently
explore the range of motion of an extinct vertebrate. If someone
chooses to depict (by silhouette art) a pose other than the ONP, then
it would be important to make that clear (visually by taking the
effort to indicate the concomitant displacement at the intervertebral
joints, and perhaps by an accompanying annotation in the text or
title of the artwork). I mentioned the _Apatosaurus_ mount at the
Yale Peabody to attempt to deflect some readers from dismissing my
words merely as a rant about a few silhouette drawings, or about a
particular artist. The issue is one of maximizing the scientific
utility of a reconstruction (be it 3D, as in a physical mount that
requires lots of plaster, or 2D as in a pen-and-ink illustration).
3) I agree that the utility of a 2D digital photo-reconstruction (as
opposed to a 2D pen-and-ink illustration) ultimately depends on the
original artwork. Again, I caution to first get the scale correct,
as one can otherwise naively end up with pretty silly reconstructions
of gopher-hunters and, on that basis, advocate giving up on ONP as a
scientifically useful concept. Regarding what to do with any
obvious distortion I suggest interpolating the geometric mean of the
curvatures (i.e. pairwise tangents defined by the long axis
dimensions) of the vertebrae adjacent to the distorted vertebra. For
an isolated vertebra that doesn't fit with its neighbors, that fact
should be visually obvious for what it is: the given vertebra is
distorted, and that I thought goes without saying. If there are
multiple, subtly distorted vertebrae in a region, then this approach
will not yield useful results, hence my explicitly annotating the
reconstruction of _Diplodocus carnegii_ (CM 84) where that occurs,
plus discussion to that effect in the text.
4) Regarding the relationship between osteological neutral pose
(ONP) and the habitual (whatever that means) pose, the field will be
assisted by more workers attending to this issue. Regarding
hartebeest and wildebeest, it would be scientifically of value to
start from the osteology, and reconstruct the ONP of each, and see if
it reflects any difference in the habitual poses. Someone has got to
do that before jumping conclusions. ONP will remain a useful
starting point regardless, as it then would be a standard on which to
quantify differences among related taxa in habitual pose. Think
about it a moment, please: how otherwise can one describe neck
posture in a useful manner than to base it on some osteological
neutral point? Think freezing point of water: a useful neutral
point for anchoring temperature scales. We likewise need a means for
describing degrees of dorsiflexion or ventriflexion, and the zero
point would be the ONP. It's not meant to be an inflammatory or
radical notion. Just scientifically useful.
5) Regarding whether pleurodiran turtles really disarticulate their
zygapophyses, I'll contact someone who did a Ph.D. dissertation on
those very necks. Based on his personal communication to Mike
Parrish and myself when we visited him (soon after a DML comment to
this effect), this is a myth. But let's look at it dispassionately
and carefully. It is of significant importance to find cases where
vertebrates voluntarily (and repeatably) disarticulate their
zygapophyses. If there are indeed any such vertebrates. It is not
the case regarding camels; they seem to bend so far back that the
zygapophyses must disarticulate, but they remain in articulation, and
are prevented from doing so by an osteological adaptation.