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Re: Sauropods Then and Now



> Date: Tue, 12 Jul 2005 19:09:51 -0400
> From: mjmurphy <4mjmu@rogers.com>
> 
> Older books on sauropod behavior treated them as slow moving
> swamp-dwellers whose diet was aquatic vegetation, but this changed
> about when?  I vaguely recall pictures of sauropods (brachiosaurs?)
> feeding from the tree-tops from about the mid-70s.  Is this the
> right time frame?  And I recall the motivation for this new view
> being the discovery of remains from upland environments.  Or not?

I can't help you much with timing, but one important paper is Coombes
1975, which made a compelling biomechanical argument for the
terrestriality of sauropods, based on the deep and (relatively) narrow
torso.  Is is certainly true that many sauropod specimens have been
found in geological settings not consistent with swampland: for
example, Dodson et al. (1980) concluded that the sauropod-rich
Morrison Formation was seasonally dry.  Alexander (1989) pointed out
that the feet of sauropods are the most compact of any terrestrial
animals, so that they would have become mired in swamps if they tried
to live there.  The taphonomy of the _Brachiosaurus brancai_ holotype
HMN SII confirms this, as it was found with the limbs mired in an
upright position (Russell et al. 1980).  Also the pneumatisation of
the skeleton (see e.g. Wedel 2003a, 2003b) is best interpreted as a
lightening adaptation for terrestrial life.

> More recently, however, there has been much talk on this list of
> certain sauropods (diplodocids? or others as well?) perhaps being
> designed for a semi-aquatic environment after all.

I've never heard of this.  Reference, please!

 _/|_    ___________________________________________________________________
/o ) \/  Mike Taylor  <mike@miketaylor.org.uk>  http://www.miketaylor.org.uk
)_v__/\  "What is this talk of 'release'?  Klingons do not make software
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         Programming Mantra


REFERENCES

Alexander, R. McNeill.  1989.  Dynamics of Dinosaurs and Other Extinct
Giants.  Columbia University Press, New York.  167 pp.

Coombs, W.  1975.  Sauropod Habits and Habitats.  Palaeogeography,
Palaeoclimatology, Palaeoecology 17: 1-33.

Dodson, Peter, A. K. Behrensmeyer, Robert T. Bakker and John
S. McIntosh.  1980.  Taphonomy and paleoecology of the dinosaur beds
of the Jurassic Morrison Formation.  Paleobiology 6 (2): 208-232.

Russell, D., P. Beland and J. S. McIntosh.  1980.  Paleoecology of the
dinosaurs of Tendaguru (Tanzania).  Memoirs Societe Geologie Francais
59 (139): 169-175.

Wedel, Mathew J.  2003.  The Evolution of Vertebral Pneumaticity in
Sauropod Dinosaurs.  Journal of Vertebrate Paleontology 23(2):344-357,
June 2003

Wedel, Mathew J.  2003.  Vertebral pneumaticity, air sacs, and the
physiology of sauropod dinosaurs.  Paleobiology, 29(2), 2003,
pp. 243-255