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Re: Again: origin of bird flight

At 06:37 PM 17/03/01 +0100, David Marjanovic wrote:
True, but I disagree with the "Pouncing Proavis" hypothesis:
1. It's mantra time: There Were No Trees At Solnhofen. (I don't think 3 m
high bushes are suitable for such pouncing.)

Further mantra: so what? Just because Archaeopteryx happened to live in the Solnhofen ecosystem does not mean that (a) it evolved there, (b) flight evolved in that type of ecosystem or (c) Archaeopteryx really is the First Bird so anything about how it lived apples directly to how flight evolved. There are plenty of closely-related living birds today that occupy quite different habitats (not to mention other groups of animals - if baboons were the only fossil primates would we be forced to conclude that primates did not evolve in trees?). Archie just happened to be the one that fossilized - it could have had very close relatives in tall forest elsewhere.

2. *Archaeopteryx* (and *Microraptor*, and even the larger
*Sinornithosaurus* whose skull is only 13 cm long) surely didn't hunt prey
that could be hunted this way. Insects, or, in the case of Archie, fish seem
more probable (and *small* tetrapods in the case of *Sinornithosaurus*).

Or small frogs, lizards etc - which (in forests) probably lived in trees too, just as they do today, and sat on leaves or thin limbs (I still think pouncing up, rather than down, followed by parachuting, makes more sense).

Or for steering underwater... just like pelicans do today with their stiff
tail feathers. (c) Ebel 1996

I'm afraid I can see not the slightest resemblance between Archaeopteryx and any swimming bird. The limb and body proportions are about as wrong as they can be - I would be utterly astonished if it could, or did, swim underwater.

Fits underwater flight, too.

Underwater flyers today are highly specialized in ways Archaeopteryx simply is not. For one thing, birds that do this today (alcids, penguins, scoters) have long bodies and short limbs - quite unlike Archaeopteryx.

Just a question here -- is there still anyone on this list who thinks that
the abovementioned groups are not secondarily flightless? :-)

Well, I for one think that the matter is far from proven, though suggestive.

Ronald I. Orenstein Phone: (905) 820-7886
International Wildlife Coalition Fax/Modem: (905) 569-0116
1825 Shady Creek Court
Mississauga, Ontario, Canada L5L 3W2 mailto:ornstn@home.com