Re: ceratopsian front limb stance

["David Marjanovic" <david.marjanovic@gmx.at>]

> >  The running _T. rex_ on the homepage (as well as the background) is
> > admirable, but why does the _Triceratops_ sprawl its forelimbs?
> >
> > Dear Mr. Marjanovic and list members,
> >
> >     Because that's how it really walked.

Hm. I've had another look at HP Jordan Mallon's homepage and have found that
although the elbows are quite splayed outwards, the hands do fit the
*Ceratopsipes goldenensis* tracks, so "sprawling" really is an exaggeration.

> >     I have just completed six different ceratopsian sculptures for The
> > Discovery Channel's new "When Dinosaurs Roamed America" CGI documentary
> > program that is coming out next summer. I have worked extensively with
Dr.
> > Jim Kirkland and Scott Samson with a chaser of the Paleo Artist Bob
> Walters,
> who has and is working with the Smithsonian on  computer scanned
ceratopsian
> frount limb orientation and locomotion, with specific study of
> Triceratops.
>     Here's what was found. According to The Smithsonian's research, based
> on
> computer analysis, Ceratopsians cannot fit their frount legs under their
> bodys, and do indeed have an elbows out appearance.This is of coarse
> something that paleontologists had written on their Post It notes on the
> fridge well over a century ago.
>     All three of my technical advisors agree strongly with elbows out.

This is also dependent on the anatomy of the rib cage. Someone (HPs GSP or
George Olshevsky) has written a couple of years ago that restoration of
dinosaur skeletons often have the ribs too far apart so that the rib cage is
too wide, which causes slight misalignment of the hindlimbs and great
misalignment of the pectoral girdle and therefore the forelimbs. The sterna
[if present?] and coracoids most certainly touched at the symphysis, and the
position of the scapulae on the ribs looked like in other dinosaurs in
lateral view. There is general agreement, AFAIK, that ceratopsian elbows
could not be fully extended (more precisely, they were extended already when
upper and lower arm formed an angle < 180°, just like e. g. rhino elbows and
theropod knees), but not whether the elbows pointed laterally or caudally,
MHO favoring the latter.

> Hugs,
>
> Cliff Green

Nice of you. :-) :-)