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Re: Apsaravis ukhaana, new Mongolian fossil bird



In a message dated 1/11/01 4:52:18 PM EST, kinman@hotmail.com writes:

<< I wish it had been one of your dinobirds, but if BCF is correct, I 
 would think most dinobirds would have occurred in the Jurassic, and perhaps 
 even driven to extinction by Early Cretaceous times.  Even if some of them 
 made it to the Upper Cretaceous, wouldn't competition probably restrict 
 their populations in distribution, numbers of species, and/or numbers of 
 individuals (making discovery very improbable)? >>

Right. Most flying dinobirds would have occurred in the Jurassic; surviving 
dinobirds in the Cretaceous surely include secondarily flightless forms, 
which would appear in the fossil record as maniraptoran theropods. Some 
flying dinobirds may have survived as relicts (e.g. Rahonavis), but most 
would have been displaced by their more capable flying descendants. Situation 
is similar to displacement of tailed rhamphorhynchoid pterosaurs by tailless, 
more aerially efficient pterodactyloid pterosaurs.