Re: Science feather strength debate

[Dann Pigdon <dannj@alphalink.com.au>]

On Mon, Nov 8th, 2010 at 10:51 PM, David Marjanovic <david.marjanovic@gmx.at> 
wrote:

> > > I'll only add that in several papers published in the 1970's, John
> > > Ostrom proposed that _Archaeopteryx_ could not fly. He even
> > > stated that the position of the glenoid prevented the humerus from
> > > being raised above the shoulder.
> >
> >  I wonder whether Archie had enough flexibility in the elbow and wrist
> >  to compensate for this? Could it not have utilised a flight stroke
> >  more like that of modern bats, with a lot of flexibility in the
> >  various wing joints, rather than having the more stiffened wing
> >  structure seen in modern birds?
> 
> I'm not sure what you mean. In what way do bats have "a lot of 
> flexibility in the various wing joints"?

I was refering to the work of Kenneth Breuer and Sharon Swartz on bat flight 
kinematics over the 
years, most recently:
http://www.nytimes.com/2010/10/12/science/12obbat.html

I doubt Archie had the wing flexibility of a modern bat, but perhaps the wings 
weren't as rigid as in 
modern birds? In which case we really shouldn't be comparing any individual 
wing feature (like the 
glenoid structure) to modern birds, and concluding that powered flight was 
unlikely, but rather be 
looking at the wing structure as a whole and as an independant system to that 
seen in modern 
birds.

You often hear of Archie being a 'poor flyer', but that's only in comparison to 
modern birds. I think 
that's an unfair comparison though - a bit like criticising Isaac Newton for 
not mentioning relativity 
or quantum physics. For its time, and as compared to other dinosaurs, Archie 
was probably quite 
good at aerial locomotion (relatively speaking). I also suspect it was doing so 
in a manner quite 
differently to that of modern birds.

-- 
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Dann Pigdon
Spatial Data Analyst               Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj
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