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RE: Tyrannosaurs with leathery skin, etc.

On Sunday, November 28, 1999 11:26 AM, TomHopp@aol.com [SMTP:TomHopp@aol.com] 

> Good questions. As I recall, there are some birds which have feathery-tipped
> scales on their legs, and these either get more or less feathery as they
> mature, I forget which. That might be a starting place to try gaining some
> data on the subject. Regarding more primitive theropods, I like the idea that
> bipedalism itself requires warm-bloodedness (was this a Bakkerism?), as a
> biped would otherwise tend to slow down and fall over when cold. You can draw
> your own conclusions, all the way back to Herrerasaurus, from there.
> - Tom Hopp

Some degree of bipedalism goes back as far as Euparkeria, a pretty basal 
archosaur (outside the crown group).  There are even some reasonable candidates 
for *obligate* bipedalism on the croc side of the family, assuming 
Ornithosuchus is on that side.  See, for example, 
 http://rainbow.ldeo.columbia.edu/courses/v1001/10.html. None of this 
absolutely precludes endothermy, but it isn't particularly encouraging.

  --Toby White

Vertebrate Notes @
http://www.dinodata.net and