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Re: New paper on pre-Archaeopteryx coelurosaurian dinosaurs



Actually, I'd refer you to Lawrence Witmer's excellent essay on this subject in 
Mesozoic birds: above the heads of dinosaurs. On page 6 and 7 he notes that 
Archaeopteryx shares several characters with definite avians, and lacks 
autapomorphies that would rule it out as being ancestral to later birds. On 
this subject he concludes by saying that Archaeopteryx "...in a strictly 
phylogenetic sense, may legitimately serve as a model for an avian ancestor".


On Oct 27, 2010, at 8:12 AM, vilandra@austin.rr.com wrote:

> Not sure what you're doing, but I thought archaeopteryx was an evolutionary 
> dead end, and birds split from the other therapods very early.   Of course, 
> an older version has maniraptors their ancestors.
> 
> Yours,
> Villandra Thorsdottir
> Austin, Texas
> 
> ----- Original Message ----- From: <vultur-10@neo.tamu.edu>
> To: "dinosaur" <dinosaur@usc.edu>
> Sent: Tuesday, October 26, 2010 8:59 PM
> Subject: Re: New paper on pre-Archaeopteryx coelurosaurian dinosaurs
> 
> 
>> I thought Gigantoraptor was ~2 tonnes, much smaller than e.g. Tyrannosaurus 
>> or Spinosaurus. Has its size been revised upwards?
>> 
>> ----- Original Message -----
>> From: "Tim Williams" <tijawi@gmail.com>
>> To: dinosaur@usc.edu
>> Sent: Tuesday, October 26, 2010 7:24:05 PM GMT -06:00 US/Canada Central
>> Subject: Re: New paper on pre-Archaeopteryx coelurosaurian dinosaurs
>> 
>> On Wed, Oct 27, 2010 at 5:40 AM, Jason Brougham <jaseb@amnh.org> wrote:
>> 
>>> I hope that no one goes overboard about the new Xu et al. paper. As the 
>>> authors state themselves:
>>> "such a phylogenetic hypothesis would have significant implications for the 
>>> reconstruction of the
>>> theropod - bird transition but it has yet to be tested by quantitative 
>>> analysis."
>> 
>> 
>> IF - and this is still a big IF - the topology showing
>> Oviraptorosauria inside Aves is supported, then it means that the
>> largest known theropod (_Gigantoraptor_) is a bird.
>> 
>> (I know that being a member of Aves does not necessarily mean that
>> something is a 'bird', the latter being a vernacular term.  But
>> still... _Archaeopteryx_ is almost always said to be a 'bird', and if
>> oviraptorosaurs are closer to modern birds than ol' Archie is, well
>> then there's no reason why they shouldn't also be called birds.
>> Sternberg was right after all when he thought _Caenagnathus_ was a
>> bird!)
>> 
>> But I'm getting way ahead of myself.  This phylogenetic hypothesis has
>> yet to be tested.
>> 
>> 
>> Cheers
>> 
>> Tim 
> 

Jason Brougham
Senior Principal Preparator
American Museum of Natural History
jaseb@amnh.org
(212) 496 3544