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Re: Sauropod Reference
On Sun, 22 Oct 1995 Dinogeorge@aol.com wrote:
> >Upchurch, P. 1995. The evolutionary history of sauropod dinosaurs. Phil.
> >Trans. R. Soc. Lond. (B) 349, 365-390.
> I've been looking forward to this one for a while. I can't imagine
> _Opisthocoelicaudia_ as being closely related to titanosaurids at
> all--opisthocoelous caudals versus procoelous caudals, bifid neural spines
> versus single neural spines, et al. I'll have to see a very powerful case
> against these basic features.
You won't like it. It's largely cladistic. However you will have to agree
that the opisthocoelous caudals of Opisthocoelocaudia is an unusual
autapomorphy for this genus and tells us nothing about what it is related
to. As for bifid nueral spines they seem to pop up time and again in
sauropod evolution (Euhelopodids, Camarasaurids, Diplodicoids and
Opisthocoelocaudia). This is one of those characters I was reffering to when
I talked about rampant convergence within the Sauropoda, in an earlier
posting. I don't know what it would be but it would seem that having bifid
nueral spines was a structural advantage to a gigantic long necked creature.