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Re: Comments on _Longisquama_ in _Science_.




<That's important, Ruben says, because he and most other scientists think
structures as specialized as feathers must have evolved only once, almost
certainly in some ancient member of a vast group of creatures called
archosaurs.>

Hmmm. But according to Ruben, Martin, Feduccia, et al. the skeleton of a theropod and a bird could evolve twice while looking so similar and sharing so many osteo characters? This statement about feathers evolving only once would seem inconsistent with their previous statements on convergence of body plans. Furthermore, one could argue (as has been done, although I forget the reference) that endothermy evolved only once since it is also very complicated and yet it appears that mammals and birds (and perhaps dinosaurs and pterosaurs) all developed it. So again, to be consistent, feathers or feather-like structures could have evolved more than once.


Matt Bonnan

"... Hey mighty Brontosaurus don't you have a lesson for us? / Thought your rule would always last / There were no lessons in your past / You were built three stories high / They say you would not hurt a fly / If we explode the atom bomb / Would they say that we were dumb? / We're walking in your footsteps ..."
-- The Police, "Walking in Your Footsteps"
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