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Re: Phylogeny of Maniraptora



On Fri, Jun 06, 2003 at 03:31:26PM -0500, Tim Williams scripsit:
> Graydon <oak@uniserve.com> wrote:
[snip] 
> >If it's a maniraptoran, it can flap.  (maybe not *well*, but it can
> >flap.)
> 
> But, *why* would it flap?  You've explained the *how*, but not the
> *why* of the predatory stroke --> flight stroke pathway.

Why wouldn't it flap?  Ratites flap when running.

Balance and just plain old reflex reaction will do as reasons to flap;
it doesn't even have to happen consistently, just enough to get on the
bottom rung of the WAIR ladder, and you'll get a transition from a pure
predatory stroke to an aerodynamic stroke.

Once the aerodynamic stroke gets useful, you get selective tension
between the uses; some of those get you flyers, and then kinds of
flyers. I suspect some get you sharp turns and impressive leaping
behavior, handy things if you're too big to fly and have a predatory
strategy involving downward kicks with your hind feet.  Gods know how
you could test that from fossils, though.

-- 
oak@uniserve.com | Uton we hycgan    hwaer we ham agen,
                 | ond thonne gedhencan    he we thider cumen.
                 |   -- The Seafarer, ll. 117-118.