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Re: Archeopteryx: bird/not Aves



>>Where do Troodontids fit into Paul's proposed scheme?<<
I think (but I'm not sure) that Troodon and its kin are related to the
ornithomimes and tyrannosaurs and evolved their sickle-claws convergently with
the dromaeosaurs

>>This proposal does
make sense to some degree (vestigial semi-lunate carpal and sternal carina,
and it takes care of that whole temporal problem).  What does he say about
the opisthopubic condition (pubic "boot" not pointing backwards as far as in
Archaeopteryx),<<
I don't know.  Perhaps it is a trait from the achaeopteryx-like ancestor of the
domaeosaurs?

>>and the elongate tail of Dromaeosauridae?<<
When back on the ground, the dromaeosaurs needed a longer tail to balance
themselves so they could move around with greater agility as they became
larger.  Of course, that wouldn't work if Achaeopteryx has fewer caudal
vertebrae than the dromaeosaurs, because it is hard to evolve new vertebrae, but
it would be possible if it were only a lengthening of the vertebrae already
there.

Dan