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Re: cursorial flapping -Reply



>       One preadapation towards flight that arboreality may cause is 
>developing the arms and putting them in the right position. I don't know 
>how constrained the movement of theropod arms are, but whenever I see 
>squirrels, I notice how sprawled out the legs are when they run over the 
>ground. When they get up in the trees, the arms spread wide to grip the 
>trunk. 

As I have suggested, squirrels, or at least flying squirrels, may be a very
poor or incorrect model for the origin of flapping flight in a largely
bipedal protobird.  That may be why they have produced highly specialised
gliders, not flyers (as have such ecologically-similar groups as possums and
anomalurids).

>       Various other points- for "predator free" evolution of ratites, 
>after the dinosaurs went exinct, things were pretty "predator free" for a 
>while. And flightless Cretaceous forms may have evolved opportunistically 
>after the end of the Jurassic, it may be that predators were not doing 
>especially well for a few million years.

Except that we have no really strong evidence that ratites evolved at that
time - the early fossil record of ratite groups is actually pretty lousy.

> I'm guessing that the 
>flying groups far surpass the nonflying groups in diversity among the 
>insects. Well, actually, I don't think weevils can fly, can they? Change 
>that to "flying and secondarily flightless insects".

Weevils can certainly fly, though I believe there are some secondarily
flightless species somewhere.  Certainly flying insects far outnumber
flightless ones in both numbers and diversity, especially if you include
things like ants which are only flightless at certain times and for certain
castes.

>       I live on an archipelago, and at home, I see the crows flying 
>over the water quite frequently, sometimes in large numbers, and they 
>enjoy foraging on the ground, in trees for berries, or in the tidepools 
>for whatever the heck it is they eat down there- fish, isopods, snails, I 
>don't know. This seems like a lifestyle that Archaeopteryx might have
> enjoyed.

As I suggested, perhaps Archaeopteryx flew over water to reach predator-free
nesting islands.  From a casual inspection I would find it hard to believe
that it was anything but a generalist forager (like a crow).
--
Ronald I. Orenstein                           Phone: (905) 820-7886 (home)
International Wildlife Coalition              Fax/Modem: (905) 569-0116 (home)
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