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Re: Scaly tyrannosaurs; fact or fiction?



On Mon, 1 Jan 2001 20:32:08   
 T. Mike Keesey wrote:
>On Mon, 1 Jan 2001, Steve  Brusatte wrote:
>
>> If there were, indeed, Tyrannosaur skin impressions found, then I
>> would be curious to see if they show any evidence of feathers.  Most
>> cladograms show Tyrannosaurus well within the range of feathers
>
>Not necessarily. Some cladograms do place them outside of
>Clade (_Sinosauropteryx_ + _Passeres_) (the known scope for feathery
>integument), and I think all place them outside of
>Clade (_Protarchaeopteryx_ + _Caudipteryx_ + _Beipiaosaurus_ + _Passeres_)
>(the known scope for feathers, probably). Phylogenetic bracketing
>is ambiguous on the case of tyrannosauroid integument, unless you follow a
>phylogeny where Tyrannosauroidea share more recent ancestry with Aves than
>_Sinosauropteryx_ does.

Actually, I should have said integument.  I, like many, have no real concrete 
idea where (exactly) on the phylogenetic tree actual feathers evolved, although 
we are getting a much clearer picture of that with all of these new 
discoveries/papers.

Regardless, many cladograms (although not all as Mike pointed out) do put 
Tyrannosaurus in the clade where feathery integument is present.  At least 
until a really good specimen is preserved (not too likely in the Montana-South 
Dakota-Alberta region) we will probably not know for sure if such integument 
was present on Tyrannosaurus.

Steve

Steve Brusatte
Dino Land Paleontology
http://www.geocities.com/stegob


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