Re: paleonet Origin of birds

[Dinogeorge@xxxxxxx]

In a message dated 4/11/2005 12:48:57 P.M. Pacific Standard Time,  
tdemko@d.umn.edu writes:

>>Dr. Frances James, an ornithologist/ecologist from Florida  State 
University, gave a talk here last week where she supposed that the  
Maniraptora, including oviraptors and dromeosaurs, were large 
flightless  birds. It seems that flightlessness has evolved in birds 
numerous times, and  its adaptations completely swamp the characters 
used in typical cladistic  analysis of bird-dinosaur relationships. She 
also was able to point out  several bird-specific (i.e. vestigial flight 
characters) features present in  some maniraptors.

It was almost convincing...I'd like to hear  more!<<
 
Well, I've been pushing this view for some 15 years now. There is indeed  
rampant convergence in dinosaur and theropod lineages as a result of secondary  
flightlessness, making cladistic analysis very problematic. Think of moas,  
giganornithids, phorusrachids, etc., etc. Forelimb reduction and hindlimb  
enlargement, as adjuncts of secondary flightlessness, occurred repeatedly  in 
Cenozoic birds, why not also in Mesozoic birds?