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Re: Feduccia's Errors



 From: GSP1954@aol.com
 > 
 > The similarity of the pubes of Archaeopteryx and theropods are dismissed. In
 > fact the pubic shafts of the former and dromaeosaurs share a plate-like,
 > slightly angled transverse cross-section not found in any other archosaurs. 

Yeah - in fact if Dromaeosaur pelvises had been known back when
the dinosaur orders were named, they might have gotten the name
Ornithischia.
 > 
 > AF states that the "thecodont" Postosuchus is close to the origin of
 > carnosaurs. This view is held by few if any today. All crurotarsal
 > ankled archosaurs such as Postosuchus belong to the group that
 > includes crocodilians, so Postosuchus is a near crocodilian, not
 > a near dinosaur. 

Urk, I haven't gotten that far yet.  This is silly.  The only other
person who I have  seen recently espouse a similar view was Chatterjee,
when he suggested that tyrannosaurs were descended from poposaurids!

 > I happen to agree with AF that birds almost certainly evolved flight from
 > high places ... Where we diverge is
 > in his unsubstantiated insistence that small theropods - despite many having
 > long clawed fingers and bird-like toes - were not good climbers. 

Indeed, _Compsognathus_ could, with ver *minor* modifications,
be as good a climber as a squirrel.  (I think the specialized
two-fingered hand may preclude good climbing in that genus, but
it has enough close relatives with three-fingered hands to make
a form that differs mainly in retaining three fingers quite plausible).

 > Of course, I have been guilty of committing a "fantasy" by illustrating my
 > small theropods with feathers, for which "there is no evidence", and would
 > hinder the running of a biped by producing drag

Gack.  I am almost losing interest in finishing reading the book!
Feathers produce excess drag in cursorial forms!?!?!?!  I guess
flying birds don't have to worry about drag :-)

 > AF concludes that body insulating feathers are not necessarily correlated
 > with endothermy despite the absence of a single living insulated endotherm in
 > the modern world.

I assume a typo here - you mean no living insulated *ectotherm*, right?

As near as I can tell, insulation would actually be *detrimental*
to an ectotherm, as it would interfere with heat uptake from the
environment. (Insulation does work both ways, after all).  Imagine
how much longer a basking lizard would take to warm up if it had
feathers or fur.

A full body covering of insulation pretty much *requires* that
heating be almost entirely internal, and thus makes the animal,
by definition, an endotherm.

[If we can find a Sinosauropteryx specimen which shows insulation
off of the mid-saggital plane, then I would say endothermy in
small coelurosaurs is firmly and finally establshed].

swf@elsegundoca.ncr.com         sarima@ix.netcom.com

The peace of God be with you.