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Re: Vertebral spines on sauropods...




Brian Franczak wrote:

> I would expect near-perfect bilateral symmetry in the living animal, no?
> If the spines are not straight or parallel, that would indeed seem to
> indicate to me distortion after death and fossilization. Can anyone
> supply a reason to think otherwise?

Just another guess from the non-expert, here. The antlers of various deer, as
well as the horns of sheep, show a good deal of variation, and in addition to
the functional aspect of these structures, they also serve for sexual display
and possibly (?) for identification, both for species and for individuals. A
possible reason for asymmetrical spines in Amargasaurus could be individual
variation for the sake of identification. This would only make sense,
however, if the spines formed spikes instead of a sail. I realize that
mammalian horns are not analogous to neural spines on dinosaurs. Very few
structures in modern animals are analogous to the dinosaurian structures with
dubious functions.  Also, about spines forming spikes, I don't think any
other animal had spikes formed directly from vertebral bones, but several
stegosaurs had spikes/plates in varying combinations, and I haven't heard too
many people wanting to stretch a sail along their backs. Personally, I like
the sail look better, and it makes more sense to me; I'm just trying to play
devil's advocate here...

>
>
> Brian (franczak@ntplx.net)
> http://www.paleolife-art.com