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Re: Basal Theropod Arm Position



You aren't going to get the arms out of the water, so I'd go with the
elbow at maximal flexion and the humerus tucked in and retracted to
the point where the forearm and hand are horizontal.  That's
speculation of course, but I'd think that's about the minimum drag
you're going to get out of it while also making it possible to employ
their forearms if needed.

Obviously swept back and tucked is another possibility, and perhaps
either could be used depending on the situation?

-Scott

On Sun, Sep 18, 2011 at 4:56 PM, Harris, Jerald <jharris@dixie.edu> wrote:
> A hypothetical question for y'all: in what position, d'you think, would a 
> basal theropod, such as a coelophysoid, hold its arms while swimming?  Given 
> the absence of the bird-like wing-folding ability at all joints, and given 
> the relatively limited flexibility at the shoulders and elbows described by 
> Carpenter (2002), what's the alternative in order to prevent the arms from 
> acting as baffles and maximize hydrodynamicity?  Would they be kept swept 
> backward, croc-like?  Even if Carpenter's limits are off, which I might 
> expect based on the more recent works that have shown that dinosaurs probably 
> had great, heaping gobs o' cartilage at the joints, which likely enhanced 
> mobility, I still don't see coelophysoids having anything close to a 
> wing-like folding ability...
>
> Carpenter, K. 2002. Forelimb biomechanics of nonavian theropod dinosaurs in 
> predation; pp. 59–76 in Gudo, M., Gutmann, M., and Scholz, J. (eds.), 
> Concepts of Functional, Engineering and Constructional Morphology. 
> Senckenbergiana Lethaea 82. E. Schweizerbart'sche Verlagsbuchhandlung, 
> Frankfurt.
>
> --
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Dr. Jerry D. Harris
> Director of Paleontology
> Dixie State College
> Science Building
> 225 South 700 East
> St. George, UT  84770   USA
> Phone: (435) 652-7758
> Fax: (435) 656-4022
> E-mail: jharris@dixie.edu
> and     dinogami@gmail.com
> http://cactus.dixie.edu/jharris/
>
>
> "Normal" is just a setting on the
> washing machine.
>
>                         -- Bernice Lewis
>



-- 
Scott Hartman
Scientific Advisor/Technical Illustrator
(307) 921-9750
website: www.skeletaldrawing.com
blog: http://skeletaldrawing.blogspot.com/