Re: Sort Your Story Out! (Was: 2 refs that were once new...)

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: "Nick Longrich" <longrich@alumni.princeton.edu>


> Perhaps someone could answer this:
> How exactly did they (or would anyone) measure the vane
> asymmetry in the Berlin Specimen? The impression I had of the
> specimen is that all of the feathers are overlapping and so its
> difficult, if not downright impossible, to get a good idea of the
> width of the posterior vane. Until I see this specificially
> addressed, I'm very skeptical of conclusions that the feathers were
> symmetrical.

In order to avoid retyping the whole paper I just presented the results and
ignored the methods. Well:

"In the Berlin and London specimens the feathers are embedded in wings and
therefore overlap each other. The distal ends of some of the feathers are
sufficiently exposed to make measurements of vane asymmetry at the 25%
position from the feather tips. We measured primary feathers 4, 5 and 6 of
the left wing of the Berlin specimen and primary feathers 3 and 4 from the
left wing of the London specimen. Vane asymmetry averaged 1.44 for the
London specimen and 1.46 for the Berlin specimen (Fig. 2d)."

This figure shows that *Archaeopteryx* is outside the range of flying birds
and in the peak of the range of flightless ones (which is _something_ like
0.5 to 4.0). The single feather (2.2) is at the lower end of flying birds
(2.22) and far from *Archaeopteryx*.

Fig. 1: "[...] Both feather position in the wing and position on the feather
have significant effects on the extent of vane asymmetry. There is no
significant interaction of these effects."

This means that measurements of the same feathers in the wings of 17 flying
birds from 17 families, taken 5 %, 25 % or 50 % away from their tips,
cluster quite tightly around 3 curves, and that asymmetry generally
decreases from primary 1 (the outermost) inwards.