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RE: Modelling large theropod movement



While it is true that this ground has been covered numerous times and
many reconstructions of walking T rex have been done, all of them suffer
serious problems. I question how much understanding about anatomy and
locomotion these "artists" have. For example, legs don't move in a
single parasagital (back and forth) plane (as seen in the Train
model/video), rather he body shifts over the supporting leg (the body
appears to rock from side to side during locomotion). Too many
illustrations show the leg straight down so that only half the body
(left or right side) is supported by the leg. Guess there must be an
antigravity pack on the other side. Watch an ostrich or emu walking for
example. 

Furthermore, the knees (a good landmark), don't move back and forth
parallel to the vertebral column either because the knee would hit the
belly. Rather, the knees move forwards and out. This can be seen quite
well in animals running away from you. In T rex and many dinosaurs, the
acetabulum (hip socket) is actually angled slightly backwards so that
the femur head rotating will move the knee at an angle away from being
parallel to the vertebral column.

Ken

Kenneth Carpenter, Ph.D.
Curator of Lower Vertebrate Paleontology & Chief Preparator
Department of Earth Sciences
Denver Museum of Nature & Science
2001 Colorado Blvd.
Denver, CO 80205 USA

Office phone: 303-370-6392
Museum fax: 303-331-6492
---------------------------------------------------------------
For PDFs of some of my publications, as well as information of the Cedar
Mountain Project:
https://scientists.dmns.org/sites/kencarpenter/default.aspx
(if you have problems with the link, cut and paste it into the browser
address bar)
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The scientific method is a myth:
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-----Original Message-----
From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf
Of Danvarner@aol.com
Sent: Wednesday, January 09, 2008 3:14 PM
To: dinosaur@usc.edu
Cc: paleo@ncf.ca
Subject: Re: Modelling large theropod movement

In a message dated 1/9/2008 4:40:05 PM Eastern Standard Time,
paleo@ncf.ca  
writes:

<< If you could comment on:
- head position in walking,  running and standing - should it be as high
as 
is normally depicted?
-  how far the head can be moved to the side without unbalancing the
animal
-  likely postures for the forelimbs
- leg width and movement, tail rigidity,  jaw gape, anything really
wierd we 
should know about etc. >>

This is ground that has been covered numerous times.  To answer your 
questions I suggest that you watch the film of Hall Train's  mechanical
Tyrannosaurus 
skeleton at:

_http://www.amnh.org/exhibitions/dinosaurs/theropod/walk.php_ 
(http://www.amnh.org/exhibitions/dinosaurs/theropod/walk.php) 

Note the more correct position of the front limbs.

For  added detail, see Kent Stevens' DinoMorph website section on  
Tyrannosaurus:

http://www.cs.uoregon.edu/~kent/paleontology/Tyrannosaurus/index.html


DV
 



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