Re: Sauropods

[Stan Friesen <swf@ElSegundoCA.ATTGIS.COM>]

>From: Stang1996@aol.com
 > Why?  If one now accepts that smaller Diplodocoideans could
 > rear, what stops the larger ones from doing the same since they were
 > functionally nearly identicle?

Oh, most species probably could, when necessary, they just had less
reason to do so.

As to functionally identical, I think Brachiosaurus was rather
different.  Its heavy *fore*quarters and short tail would have made
rearing up *much* more difficult than in other types of saurpopds.

 >   Back to the beginning.  If all those dinosaurs really do form a group as I
 > believe, it would seem that having an upwardly arched neck is in fact
 > primative for that group, not derived; and that the evolution of the
 > "horizontal" neck of the Diplodocoideans is in fact derived: therefore
 > showing that Diplodocoideans went through a lot of trouble to gain that type
 > of neck so it had to be advantageous to some extent

I see what you are getting at. However, the ancestral condition
in the *Sauropodomorpha* is a "horizontal" neck, as it is seen is
the prosauropods, cetiosaurids and diplodocids.  This may be an
apomorphy of the sauropodomorpha versus other dinosaurs.

swf@elsegundoca.attgis.com              sarima@netcom.com

The peace of God be with you.