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Re: Vertebral spines on sauropods...



My original question regarding the "spike interpretation" of the neural
spines of _Amargasaurus_: "What animal -- living or dead -- has such a
structure?" was imprecise, and should, of course, have read: "What OTHER
animal -- living or dead -- has such a structure?" I'll blame my error
on the flu I've been suffering with for the past couple of weeks...

Thomas R. Holtz, Jr. wrote:

> That was the original assumption (although it was Salgado & Bonaparte:
> credit where credit is due, and all that...).

I've got the original '91 paper. Unfortunately it's in Spanish, a
language I am not conversant in. Does anyone know for certain: did
Salgado & Bonaparte advocate a "sail" in the paper? If so, it's odd then
that just a year later, when I was down in Buenos Aires, Bonaparte
strongly favored spikes.

> >If so, the spines must have been connected by a skin membrane (or were
> >there holes through the "sail"?
> 
> As I interpreted it, that was Brian (or Jaime's?) original question: was it
> a sail, or was it a bunch of individual isolated spikes.

It was me. And that was precisely why I asked the question. The general
consensus these days seems to favor spikes, but that idea always struck
me as odd for the very reason inherent in my original question: I know
of nothing analogous in nature. Impossible for _Amargasaurus_ then? No,
of course not. But as an illustrator, I can't sit on the fence; I have
to make a decision one way or the other -- based on research and my own
intuition -- on how to interpret the fossil as I restore the animal.
Since I'm in the process of (finally!) working on a painting of
_Amargasaurus_, I was trying to bolster my own interpretation based on
what I though made sense. Or conversely, have it shot down with
sufficient evidence to support the contrary idea. 

> I think what Brian (or Jaime?) was asking was whether the neural spines each
> emerged as a separate spike out of the fleshy part of the neck of
> _Amargasaurus_.  This is not known directly from the fossils, and is one of
> two commonly suggested model.  I can't think of any living animal in which
> we can demonstrate a neural spine forming an isolated spike.

Thank you, Dr. Holtz, for answering my question.

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