Re: New Article in Experimental Zoology

[Dinogeorge@aol.com]

In a message dated 8/23/02 7:28:07 PM EST, bruce_mortensen@Affymax.com writes:

<< Dr Feduccia and George Olshevsky would appear to be supported in the "Birds
 Are not Derived Dinosaurs /Birds Came First" theories by the following
 reference that showed up in my weekly literature search.   (George - when
 are you going to publish BCF?) >>

BCF published in popular-science form in June 1994 OMNI and in Dino Press 
#4-6 (not enuff space in either article for me to really explain how 
everything hangs together in BCF but that's the way the venues go).

Feduccia is not correct in maintaining that birds bypassed dinosaurs in 
evolving from small arboreal archosaurs. Rather, birds and dinosaurs both 
evolved from small feathered arboreal archosaurs, with different kinds of 
dinosaurs (= giant, flightless dino-birds) evolving repeatedly from different 
kinds of arboreal archosaurs throughout the Mesozoic (only a small--but 
better preserved--fraction of the total number of lineages that must have 
appeared: note intense mosaic evolution among Liaoning forms, for example). 
Liaoning finds are very significant not just in showing feathered dinosaurs 
but also in showing something approaching the true diversity of small 
Mesozoic dinosaurs, which are not usually preserved in the fossil record. 
Surely nobody believes that Liaoning area was the only place and time on the 
planet where and when such forms existed! Mesozoic world was filled with all 
kinds of mini-archosaurs (=dino-birds), just as the world today is filled 
with birds, as I noted as long ago as first printing of Mesozoic Meanderings 
#2. There were probably several different kinds of wings among the flying 
forms at first, and eventually those with the most efficient wingform (= 
maniraptorans) dominated. Good luck to cladists trying to disentangle mosaic 
relationships among the diverse array of tachytelic dino-birds, vast majority 
of which will remain hidden from the fossil record into the foreseeable 
future.

My guess is that mammal competition during the later Cretaceous made strong 
inroads into terrestrial/arboreal dino-bird diversity, so that when the 
asteroid impact destroyed the big dinosaurs, mammals beat them to the 
comeback in the aftermath. You still got occasional groups of giant, 
flightless birds (= theropods) that evolved in isolation during the Cenozoic, 
but there was nothing like theropod dominance during the Mesozoic.