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Re: Giant birds



>In a message dated 11/8/99 10:35:13 PM EST, bettyc@flyinggoat.com writes:
>
><< what about quadrepedal flightless birds like sauropods and ceratopsians?
> ;]
> 
> -Betty >>
>
>Probably evolved from tree-climbing birds that couldn't fly yet.

Wait a minute.  Do you include all dinosaur groups, including ornithischians, 
under BCF (or are we really talking about BCF here)?  I thought that BCF 
referred to theropod evolution solely.  Or are we talking about something 
different.  Now, I understand that the first ornithischians are bipedal, and 
that a case could be made for a tree dwelling ancestor, but I'm not sure that 
makes them birds.

I have thought that the radical difference in hip designs implied *two 
separate* instances of bipedal evolution (I envision several protodinosaur 
groups existing, where only the ornithischians and saurischians survived).  
Personally, I can't see a saurischian evolving an ornithischian hip, even with 
a truckload of generations.  There doesn't seem to be any advantage to the 
"new" hip design.


Rob Meyerson

***
Politicians and diapers have one thing in common. They should both be changed 
regularly and for the same reason.