Andya,
You miss the point, I understand fully that flying fish aren't true flyers, yet gliding is a plausible, I think you will agree, precursor of flight. Flying fish have managed a surface up transition.
Given that we know that they have, then we also know it's not impossible.
And yes, Microraptor gui with four wings makes a plausible link in the arboreal archosaur>bird scenario.
But in the grand scheme, they are unlikely to be anything like the ancestral bird. Why? Bird legs, like
Archaeopterix' articulate for running in a particular way, very similar to therapodan/dinosaurs.
Microraptors legs don't, & it is found more recently than
Archaeopterix fossils. This means that therapod hind limbs evolved into
Microraptor like legs, & then back again. Or archaeosaurs evolved
Microraptor legs, then bird/therapod like legs. I therefore put it to you that
Microraptor gui is actually more derived than
Archaeopterix, rather than possesses ancestral characters of all birds.
That said, the number of synapomorphies that birds & therapods share is amazing, & simply cannot be just written off to convergent evolution. I therefore put it to you that the large majority of evidence points to a therapod ancestor of birds. I'm happy to consider an arboreal therapod, of course. But haven't been convinced that the ground up hypothesis is sufficiently flawed enough to be considered inferior to the arboreal hypothesis.
I don't understand why the describers shoehorned it into Dromaeosauridae.
Presumably because it possessed dromaeosauridae/dinosaur characters & not archosaur?
Mark
[This message has been edited by mark24, 09-28-2003]
[This message has been edited by mark24, 09-28-2003]