Re: Archaeopteryx flight

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

Just found an error -- the thumbs of hoatzin hatchlings, as well as those of
*Archaeopteryx*, all extend to the end of phalanx II-1 (illustration on p.
313 of Bakker's The Dinosaur Heresies). The same figure shows anisodactyl
(rather than, say, zygodactyl) feet on a hoatzin. But I still claim that the
hands of hoatzin hatchlings are better suited to climbing than Archie's
because they are composed of considerably thicker, more robust-looking bones
(including the unguals) -- Archie has very thin fingers actually. In
*Confuciusornis* finger III is similarly thin IIRC, but I is very robust.

----- Original Message -----
From: "Tim Williams" <twilliams_alpha@hotmail.com>
Sent: Tuesday, September 04, 2001 8:37 PM

> David Marjanovic wrote:
>
> [...]
> >- apparent lack of high trees (is it possible that the few ginkgo trunks
> >that are sometimes mentioned are driftwood?);
>
> Even if these bits of ginkgo were driftwood (and I'm not saying that they
> were), then this implies the ginkgoes came from somewhere in the vicinity
of
> _Archaeopteryx_'s watery graveyard - perhaps from a neighbouring island.
At
> any rate, there were trees of some sort within a radius capable of being
> reached by _Archaeopteryx_, even considering its weak flying abilities.
>
> >- probable lack of sufficient flight abilities.
>
> Explain to me why "probable lack of sufficient flight abilities" (whatever
> that means) implies that _Archaeopteryx_ couldn't climb trees?

The only flightless AND (partly) arboreal birds (today at least), as well as
the only ones that ever start on the ground and climb up a tree trunk into
the crown, are hoatzin hatchlings. These are very small, and they have
anisodactyl feet (so the hallux can work as a prop in trunk-climbing). Most
arboreal birds never or rarely come down to the ground, and those that do
cover the vertical distance by flying, not climbing (or, usually, even
specialised trunk-walking like woodpeckers do).