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Re: Science feather strength debate



Mr. Hartman,

I am sure that your reasoning and evidence are solid, and I can certainly 
believe that Archaeopteryx had no tertiaries. Yet  I am curious why your 
excellent 2007 monograph on the tenth Archeopteryx mentions faint, fuzzy, 
impressions which "may stem from the tertiaries"? The outline drawn in figure 3 
also shows what may be tertiaries. That truly is a breathtaking paper, 
congratulations on it.

I am myself always very wary about making definitive statements about plumage 
based on negative evidence. I'm not even convinced that Scansoriopterygids 
didn't have wings.

The reason is the type specimen of Longipteryx, IVPP V 12325. (Chinese Science 
Bulletin vol. 46 no. 11 june 2001) It preserves body feathers and fuzzy 
secondary coverts, but apparently no primaries or secondaries at all. Certainly 
no large rachises are there. It has a  keeled sternum and is an obvious powered 
flier, but the primaries and secondaries just didn't preserve.

Again, I consider it risky to make conclusive statements based on reasoning 
like "if the tail feathers are preserved, why aren't the wing feathers? It must 
not have had any". Fossilization is too complex and contingent to be sure of 
such matters, and I feel like we're always one fossil away from being proven 
wrong.

-Jason

On Nov 15, 2010, at 10:36 AM, Scott Hartman wrote:

>> I'm not wholly convinced that _Archaeopteryx_ lacked humeral feathers
>> (= tertiaries or tertials).
> 
> As I presented at SVP in 2007 the tenth specimen actually demonstrates
> that Archaeopteryx lacked tertials...specifically because it shows an
> imprint by the humerus that clearly isn't a veined feather.  Whether
> it represents  an inprint from the body, or could represent some sort
> of extension of the soft "dinofuzz" material onto the arm it simply
> isn't even close to a flight feather.  And because there is an
> impression there, and moreover one made from a far more delicate sort
> of soft tissue then the relatively stiff flight feathers, it's no
> longer tenable to argue that it's some sort of trick of preservation.
> Archaeopteryx lacked tertials.
> 
> -Scott
> 
> 
> -- 
> Scott Hartman
> Scientific Advisor/Technical Illustrator
> (307) 921-9750
> www.skeletaldrawing.com

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