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Re: Limbs and niche partitioning



>>As for dinosaurs well maybe they had an aquatic phase that emphasised
hind-leg development over front. Perhaps the Ornithosuchids were more croc
like than we suspect, living up to the name. One flaw in my biological
analogy maybe the fact that sitting on a tree branch makes one semi-erect,
when you're a primate. I can't quite imagine what the archosaur ancestor of
dinos was doing that could be equivalent.<<

I think the 'aquatic ape theory' makes some logical sense and I have no bones
about that, but I doubt it applies to dinosaurs.
If one were to put an ape into the water where they could touch bottom, they
would naturally walk upright so they could ge their heads above the water.  With
less weight to hold up their legs would support them in that position.
Dinosaurs, however, do not walk like this, with their spine vertical.  If I were
to put a quadripedal archosaurs into the water, it would not stand up like an
ape, its spine wouldn't allow it.  Instead, it would probably kick off the
bottom and swim either with its tail (or if it had feathers on its arms and
certain other theories are true) by flapping its arms.

Dan