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RE: Dinosaurs to birds




        -----Original Message-----
        From:   Dinogeorge@aol.com [SMTP:Dinogeorge@aol.com]
        Sent:   Thursday, January 21, 1999 5:48 PM
        To:     Dwight.Stewart@VLSI.com; Alien4240@aol.com; dinosaur@usc.edu
        Subject:        Re: Dinosaurs to birds

        In a message dated 1/21/99 6:36:24 PM EST, Dwight.Stewart@VLSI.com
writes:

        << Or (somewhat alternately): birds were sufficiently derived (in
some way) to
         survive the KT extinction.  This is whether a bolide was the cause
or just a
         contributor.  Some evolutionary adaptation that was present in
Cretaceous
         birds, but not present in Cretaceous non-avian dinosaurs gave birds
an edge
         (in this case). >>

        Could also have been sheer luck. We have no good handle on bird
diversity
        during the Cretaceous, but if it was (as I think) quite high, then
most of the
        birds were killed off, too, and the post-Cretaceous bird radiation
would have
        stemmed from just a few (say 40-50) survivor lineages (out of, say,
500-1000).
        @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

          Point taken.  But, since we don't know how great bird diversity
was, this remains an open
        question.  One wonders if birds might have been on a decline OR
incline in diversity
        during the late Cretaceous.  It has certainly been inferred that
dinosaurs were already
        in decline when the bolide hit the ole barn.  If birds were
experiencing an incline during the
        late Cretaceous, your scenario might still work. 
           This brought another question to mind: what do we know about
Phytosaur diversity before
        & after the KT Boundary?

        Cheers;
        Dwight