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RE: Theropod origin of birds in The Auk (Jan. 2002)

Ben Creisler wrote:

>Can't recall that this item has been mentioned here:
>The January 2002 issue of the The Auk has the following 

Phew!  What an absolutely brilliant review - and by a card-carrying
ornithologist at that!  Prum has capped off his previous excellent work on
feathers and their evolution with this gem.  The article provides
chapter-and-verse support for why the evidence for the origin of birds from
theropods is so compelling.  Further,it is bursting with trenchant
criticisms on the mind-sets and methodologies behind the opposing views.
I'm certain Prum's article will send the Feducciaries into a collective
apoplectic fit.    

The paper features a number of memorable quotes; but this paragraph (from
the Conclusions) I especially liked:

"Until any credible alternative is proposed, it is time to abandon debate on
the theropod origin of birds, and to proceed to investigate all aspects of
the biology of birds in light of their theropod origin. This fertile
frontier of knowledge promises to be among the most exciting developments in
ornithology in the coming century, and ornithologists should be actively
interested in and participating in this field. The time has come for our
discipline to realize that ornithology is extant dinosaur biology.
Ornithology can only profit as a result."

The review is rounded off with this Note, which really got my heart racing
on a cold and dismal Friday afternoon:

"Note added in proof: Norell et al. (2002) describe a new specimen of a
basal dromaeosaur (possibly a _Sinornithosaurus_) from the 124 Ma old Yixian
formation of China that has preserved impressions of modern pennaceous
feathers including a rachis, barbs, and a planar vane. Occasional separation
of barbs in the feather vanes document presence of differentiated barbules
as in _Archaeopteryx_ and modern birds.  Feathers on the tip of the tail are
>19 cm long, and the beautifully preserved feathers on the upper hindlimbs
are 13.5 cm long.  This latest discovery conclusively demonstrates the
theropod origin of feathers and birds."

Did I read "barbules"?  Yep, I did.

(An "in press" _Nature_ paper is cited.  If this doesn't convert the
doubting Thomases, nothing will.)

(There's only one thing in Prum's paper I can see that might not be
absolutely correct.  AFAIK, Dodson (in his Am. Zool. article, 2000) did not
dispute the origin of birds from theropods, merely the philosophical
foundation for cladistic methodology.  But I'm picking nits.  Prum's review
is a wonderful summary of the topic.)



Timothy J. Williams 

USDA-ARS Researcher 
Agronomy Hall 
Iowa State University 
Ames IA 50014 

Phone: 515 294 9233 
Fax:   515 294 3163