Re: Archaeopteryx flight

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

> In a message dated 9/2/01 3:17:56 AM EST, david.marjanovic@gmx.at writes:
>
> << (and maths relies largely on definitions and circular logics, not to
> mention it has some gaping holes, as shown by Gödel's incompleteness
theorem
> and the number Omega.) >>
>
> These are not "gaping holes"; they're simply properties of various sets of
> axioms and of the real-number line. And circular logic is just as
forbidden
> in math as it is in science. You've been reading too many pop-math books.

I haven't read one such book. What I mean is that a mathematical proof
involves showing that 2 things are the same, that is, that 1 thing is the
same as itself -- counterintuitive sometimes, but IMHO nonetheless circular.
The circles are just hanging from definitions instead of floating around in
vacuum.

To return to the subject, I have PDW lying in front of me and remember that
the evidence for "protobeaks" is described somewhere in it, but I can't find
that... :-(
What I have found so far is (p.213):

"Protobirds the size of *Archaeopteryx* were too large for full-time
insectivory anyway; most insect-eating mammals and birds are a good deal
smaller. So what were protobirds eating? Here we need to look more closely
at *Archaeopteryx*. We have already seen how the conical teeth of some small
theropods were suitable for fishing. In fact, the very conical, unserrated,
and big-rooted teeth of *Archaeopteryx* are most like those of marine
crocodilians, whales, and the toothed diving bird *Hesperornis*. Not only
that, but the hooked and laterally flattened claws, especially those of the
hands, are strikingly like the toe claws of fish-eating bats (Figure 9-4)
[which shows that the claw curvatures are very similar indeed, a bit more so
with Archie's hand claws than with its foot claws]. So *Archaeopteryx* does
seem well-adapted for going after small aquatic organisms.* It may have swum
well too. With wings half folded, and the tail feathers slipped together
like the long tails of the strange swimming anhinga birds, the powerfully
muscled wings could have propelled it along like baby hoatzin of the little
water ouzal[**] of mountain streams. *Archaeopteryx* even lived on an island
chain, and its remains are found only in lagoons---small animal fossils have
yet to turn up archaeopterygian remains on land.[***]"

* Bakker 1986, Paul 1987, Thulborn & Hamley 1984
** Is this a species of *Cinclus*? :-9
*** Any evidence of water near *Rahonavis*? That said, it has a joint
between the scapula and the coracoid, so it was a much better flier and
surely not bound to swimming.