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>From: firstname.lastname@example.org (Ronald Orenstein)
> A thought about this: the prosauropods (as sometimes restored) appear to
> have been somewhat bipedal (is this actually true?)
> If the primitive
> sauropod condition included bipedality (I mean early sauropods - I know that
> dinosaurs in general are suposed to have arisen from bipedal ancestors) a
> horizontal neck would be the expected condition, as adopting the bipedal
> posture would be all that was required to place the neck in a vertical
Almost nobody questions the upright feeding posture of prosauropods.
The *standard* reconstructions of Plateosaurus is a picture of it
standing on it hind legs feeding on a tree. Nobody complains about that.
Except for details of foot and vertebral structure, Cetiosaurus
is almost identical to prosauropds. And Diplodocus differs mainly
in features relating to its *extremely* long neck - at least at
the gross morphological level.
Yet, despite this basic similarity, many people balk at showing
Diplodocus rearing up.
> And just to show that I'm not convinced of this, it doesn't apply to the
> gerenuk, which can certainly hold its neck bolt upright when not standing on
> its hind legs. Of course that may help it spot predators, and a gerenuk is
> basically a quadruped, not a biped.
Part of what is going on here, however, is retention of ancestral
characters. The ancesters of the gerenuk were probably *grazers*.
The general structure of the gerenuk is retained from the ancestral
This is why I can believe that *some* sauropods, at least some of
the less extremely long-necked forms, may have secondarily switched
to fern grazing.
The peace of God be with you.