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Re: 'Bridging' the gap on sauropods
>From: Robert.J.Meyerson@uwrf.edu (Rob Meyerson)
> How then, do we explain Brachiosaurus which *had*=
> to hold it's head straight up, due to the arrangment of the spinal collumn?
Well, I am not quite prepared to go *that* far. I suspect they *could*
lower their heads to ground level to drink (or at least I am not yet
convinced they could not do so).
Still, the anatomy of their neck is clearly oriented towards a
nearly vertical neutral posture. It would be odd, to say the
least, to have neck articulation like that and NOT be able to
raise the neck up.
> =46urther, it seemed that Crichton's (sp?) explanation on the long necks of=
> sauropods was wierd. He claimed that the neck was so long because it acted=
> as a counterbalance for the tail, using the analogy of how bridge supports=
> work. It seems to me that this is putting the Thagomiser ahead of the=
> Stegosaurus, wouldn't the sauropod tail make more sense as a counterbalance=
> for the head???
I agree in large part. Actually, many dinosaurs have tails fully as
long proportionally as most sauropods (diplodocids excepted). Take
a look at Dromaeosaurus or Edmontosaurus or even Stegosaurus. Thus
it is clear that a long tail is quite possible without a particularly
long neck. Also, Brachiosaurus had a rather *short* tail!!
Now it is *remotely* posible that the long neck of sauropods is an
evolutionary relic, no longer directly adaptive. But this fails
to explain the specialized necks of Diplodocus, Mamenchisaurus and
Brachiosaurus. The necks of these three, at least, fall well outside
the range of anatomy found in known prosauropods, and thus do not
look like relics to me.
The peace of God be with you.