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Re: Giant birds



In a message dated 11/8/99 5:32:05 AM EST, qilongia@yahoo.com writes:

<< Olshevsky has been calling them flightless
 birds in connection to the BCF hypothesis, and Paul in
 his SVP talk called them flightless, including
 therizinosaurs. But more than likely, troodontids and
 oviraptorosaurs are just outside the bird/dromie
 thing, or troodontids are closer to birds than
 dromies, or troodontids and dromies form a group
 exclusive of other taxa, such as birds, but then as
 deinonychosaurs are closer to birds than oviraptors,
 etc. I think there's overwhelming evidence for dromies
 as the sister taxa to birds, then, successively,
 oviraptors, troodontids, ornithomimids and
 tyrannosaurs, coelurids, and compsognathids, withing
 coelurosaurs. [By "coelurids", I include *Coelurus*,
 *Ornitholestes*, *Nedcolbertia* et al. within a
 monophyletic group, but could be wrong]. >>

However you care to arrange these taxa, the common ancestral forms of these 
taxa and birds were almost certainly capable of flying--and the closer the 
common ancestral form was to Archaeopteryx, the better flier it probably was. 
Archaeopteryx didn't acquire the power of flight overnight (the miracle that 
the "ground-up" theorists wish us to swallow) but evolved it much more 
gradually through a succession of those less flightworthy forms that were 
also the common ancestors of the various theropod groups and birds.