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Re: More Bird origins: ignore if you wish...
>"bipedality" itself is a cursorial adaptation--but it is a cursorial
>adaptation for lineages in which the forelimbs have become too modified to
>serve as portal locomotor organs.
Which could have occurred as the forearms became more adapted to grasp prey
- not necessarily for climbing, though this is certainly possible and
>Reduced forelimb size is also just such an adaptation, compensating for
>forelimbs that would have been much too big and too much in the way had they
>maintained their arboreal relative size in the cursorial forms (the forelimbs
>were reduced even in _Deinocheirus_; either that, or it was one odd-looking
I thought Tom Holtz strated that forelimb size was NOT reduced in many
>The trouble is, it is very difficult to separate cursorial adaptations of the
>kind described above from cursorial adaptations that would have arisen
>without an intervening arboreal stage.
there would have
>been no retro-hallux.
Unless the retro-hallux evolved for prey capture.
>But this isn't even speculation anymore; it's speculation squared.
So is BCF as an ecological hypothesis. BADD as I understand it is a
phylogenetic hypothesis - a quite different thing.
The point is that we have no way to prove arboreality - we can only suggest
it. And as I said earlier this has nothing to do with phylogeny in the
Ronald I. Orenstein Phone: (905) 820-7886 (home)
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