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----- Original Message -----
From: "Tim Williams" <firstname.lastname@example.org>
To: <Dinogeorge@aol.com>; <email@example.com>
Sent: Thursday, March 15, 2001 11:31 PM
Subject: Re: ABSRD BAND on Sinornithosaurus feathers
> (_Sinornithosaurus_'s ancestors, if semi-arboreal, may have
> used their feathers for drag as well. But I like the idea that
> _Sinornithosaurus_ may have been partly arboreal too - those long arms,
> a trailing edge of feathers, may have been excellent for co-ordinated
> branch-to-ground leaping).
In this case, not "Mantra: Give me more fossils", but I always wonder why
Liáoníng fossils are so incompletely prepared. At present, it is really
possible (though improbable IMHO) that *Sinornithosaurus* had substantial
> Unlike _Archaeopteryx_, the early evolution of modern birds focussed on
> increased locomotive efficiency in the air. The tail got shorter. The
> manus lost its prehensile and raptorial function - manipulation of prey
> might sully the wings, and protecting the integrity of the wing became of
> paramount importance to metornithines.
> The teeth were lost (to reduce weight?).
This came late, and 3 times independently (Confuciusornithidae,
Enantiornithiformes or so, Neornithes). All other pygostylians had teeth.
BTW, mammal teeth are really heavy, but bird teeth... hm...
> [...] Archie's mosaic morphology is best
> explained by the fact that it was adaptively advantageous to retain the
> predatory and cursorial abilities of its maniraptoran ancestors.
> Maniraptorans were the consummate predators of the Mesozoic. Why mess
Never change a running system!!! "Stabilising selection" in action.
> Keep the enhanced predatory capabilities of maniraptorans, and
> evolve flight to increase the animal's versatility as a predator (e.g. to
> swoop down from the trees onto prey below; increase the theropod's hunting
> range; escape from larger predators by flying away.)
Sounds like a good idea on the ecological niche of *Rahonavis*.
BTW, I have copied the Nature article "An Early Cretaceous pellet" which was
mentioned onlist some weeks ago. "Bird 1" has a very large claw on its 2nd
toes (larger than those of confuciusornithids); it is only seen in dorsal
view, so I can't say whether it was curved or straight, but it looks a lot
like a sickle claw. (The foot _is_ avian, as the long, retroverted hallux
> The success of the _Archaeopteryx_ "grade" of evolution is shown by the
> record of very similar birds in the Cretaceous - _Proornis_ and
> (which lived close to the end of the Mesozoic). Basal avialans didn't go
> kaput at the end of the Jurassic; in the Cretaceous they lived alongside
> metornithine (non-basal) avians that sacrificed certain features (retained
> in Archie and kin) for improved aerodynamic efficiency. Metornithines
> a punt that clawed hands, a long tail and long legs could all be dispensed
> with for the sake of improved flight performance - and it paid off.
> _Archaeopteryx_ / _Proornis_ / _Rahonavis_ took a different route.
Does this mean you know what *Proornis* looks like? How... when... where...
Anyway, this is a case of "give me more fossils"...