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Re: Sauropod ONP

A couple of additional comments:  ;-)

One potential advantage of Kent's reconstructions is
that they
eliminate the need to postulate super-high blood
pressures in sauropods which may be physiologically
difficult to accept (though sauropods such as
Brachiosaurus would still have needed a fairly high
blood pressure because of its large heart-ground
distance.) Kent's reconstuctions still
allow for sauropod niche partioning of the basis of
neck/limb differences, just not the sort that has been
seen in some of the literature.  

One aspect of this discussion which has been, I think,
overlooked a bit is that the sauropod neck was
from much smaller prosauropods, and may have been
functionally exapted from whatever the original
purpose in prosauropods was. Some sauropods
(dicraeosaurs) appear to have secondarily shortened
necks. Brachytrachelopan, in particular, looks like a
sauropod trying to be an ornithopod... :-)

In addition, one might be tempted to speculate the
rise of angiosperms in the late Cretaceous had some
effect on sauropod feeding mechanisms.  I'm wondering
if titanosaurs were doing something anatomically which
provided them with a competitive feeding advantage
over other sauropods in an angiosperm-dominated world,
since practically all upper Cretaceous sauropods
appear to have been titanosaurs. 

Guy Leahy

--- MarkSabercat@aol.com wrote:

> Well, now it's time for me to stick MY neck out.
> Living â??next doorâ?? in  
> Salem, OR, I had the chance to see the first
> computer models Kent and Mike came  
> up with at U of O several years ago, as well as
> briefly participating in the  
> earliest discussions relating to the application of
> Dinomorph's computer  
> modeling to sauropod neck osteology. Having wrestled
> on paper (like so many  
> others) with the possibilities and limitations of
> neck articulation, I want to  say 
> that for me, as a paleoartist and student of
> functional anatomy, the  
> Dinomorph studies of cervicals in the known taxa go
> far beyond the 2-D  limitations of 
> tracing and drawing overlays and are the best tool I
> know of, in  the hands 
> of those I know to be unbiased researchers, in
> tackling the problems  of 
> articulation and movement in these dinosaurs.  
> K and M started their project without any 
> preconceived notions, based their 
> models on the most extensive and available  sources
> that were accessible (both 
> original osteological materials and  accurately
> drawn views of these), 
> carefully and systematically constructed  computer
> models and then rationally 
> interpreted what they saw.... this what  science is
> all about. Probably like most 
> others, I have lots of questions and  potential
> issues about how ONP potentially 
> relates to sauropod feeding and  ecology, but we now
> have a valid and 
> valuable new reference point that will help  us to
> discuss, model and evaluate the 
> tripodal/bipedal feeding hypothesis and  others. As
> some have pointed out there 
> are the problems with postaphonomic  geodistortion
> and lack of material (the 
> Brachiosaurus pre/post zygapophyses),  but as better
> stuff comes to light we 
> can make the necessary corrections.  
> These are honest and elegant studies, and for me 
> Dinomorph has made a real 
> breakthrough in interpreting sauropod (and other) 
> dinosaur osteology.  
> Mark Hallett