Re: Disarticulating Zygapophyses, Batman!

[DinoBoyGraphics@aol.com]

Mike Taylor wrote:

> But then when you look up the reference, it just says:
>    20. J. M. Parrish and K. Stevens, unpublished data.

I have written on this before, but I will repeat my concerns.  Parrish and 
Steven's work stands as a great dichotomy.  On the one hand, it is one of the 
first techniques that (should) allow repeatable quantification of biomechanical 
analyses.  On the other hand, none of their basic assumptions has been properly 
tested (at least they haven't been published), and their methodology is not 
currently open to peer review.

For example: What is the actual relationship in extant animals between 
zygomatic articulation and possible range of cervical movement?  Now-infamous 
pictures of resting camels suggest this relationship is more complex than 
Parrish and Steven's "unpublished data" suggests.

What is the relationship between the "neutral" position of zygomatic 
articulation and how often an animal adopts this pose (vs. whether it is merely 
near the middle of the range of possible movement)?  This question would be 
extremely relevent to their published paper in Science.  Where is the data, 
especially before making extreme (and biologically unlikely) claims about 
habitual sauropod neck posture (e.g. Diplodocus carrying its head a meter off 
the ground)??

Finally, why hasn't dinomorph been made available to researchers with disperate 
views on, for example, sauropod neck posture?  The value in repeatable and 
quantifiable techniques (like cladistics) isn't that everyone comes up with the 
same answer, but that we can pinpoint the differences in their assumptions that 
lead them to different conclusions.  We are denied this with dinomorph because 
it is only in the hands of a select few, with the answers coming down to us 
like the Oracle of Delphi (and the release of a watered-down commercial version 
is unlikely to improve the situation).

So as I see it, Parrish and Steven's work with dinomorph is: a)one of the most 
promising additions to biomechanical research in extinct animals, yet: b) At 
the moment bordering on pseudoscience.  As long as grandiose claims are made in 
the popular media while the supporting data is unpublished, and as long as 
researchers with differing viewpoints are denied access to the same tools, 
their work amounts to nothing more than a cool videogame.

I truly hope that dinomorph becomes the PAUP of biomechanics.  But at the 
moment it is voodoo science mascerading as paleontology.


Scott Hartman
Zoology & Physiology
University of Wyoming
Laramie, WY 82070

(307) 742-3799