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Re: Thoughts on the new Czerkas book (long)



> Second there's the measuring question. I'm still baffled
> as to how anyone can accurately get measurements on the Berlin
> Specimen of Archaeopteryx considering that the feathers overlap
> each other, with the leading edge of each vane overlapping
> the trailing edge of the next (as in modern birds). Other than
> perhaps the separated tips of a couple of primaries, these
> measurements just can't be done as far as I can tell.

And just the separated tips of a couple of primaries is what Speakman &
Thomson measured in 1994.

"Only three specimens of *A. lithographica* have the feathers sufficiently
preesrved to measure vane asymmetry: the Berlin and London specimens and the
single feather. The single feather has an asymmetry of 2.2 at the 25 %
point, but where this feather comes from in the wing, and indeed whether it
is from the same species, is unknown [...]. 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 [sic] 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. 2_d_). The asymmetry in the primary four
feathers of *Archaeopteryx* is not significantly diferent to that of modern
flightless birds [... and substantially lower than that of modern flying
birds [...]."

> So (not having the book myself) my question is-
> are these inner or outer feathers, and are they
> separated or are the vanes overlapping each other?

And do they have unusually thick or massive shafts?

J. R. Speakman & S. C. Thomson: Flight capabilities of *Archaeopteryx*,
Nature 370, 514 (18 August 1994)