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Re: Of course nonavian dinosaurs could fly - duh

On Sat, Sep 26, 2009 at 1:54 PM,  <quailspg@frii.com> wrote:
> Denver Fowler wrote:
>> Elongate feathers on the metatarsus would be
>> equally awkward in an arboreal bird as in a
>> ground-dwelling bird.
> So... what scenarios for lifestyle are we left with?

Here's a hypothesis I'll throw out, although I'm not sure I buy it.
What if leg feathers just simply are not advantageous at all in these
early paravians, but the advantage conferred by arm feathers outweighs
that disadvantage? What if developmental constraints at first only
made it possible to develop long feathers on all limbs. Then, later,
in a clade a bit more inclusive than Pygostylia, additional inhibitors
were developed which prevented long feathers from forming on the
hindlimbs. These paravians outcompeted the others (at least, in that
size range) in part because of the advantage of not having long leg

A few predictions this hypothesis makes: 1) there are probably basal
oviraptorosaurs with leg feathers, and genes for inhibiting leg
feathers evolved independently in that group; 2) aviremigian outgroups
to Clade(Oviraptor + Vultur), currently unknown or unrecognized, are
likely to have leg feathers; 3) the development of feathers in extant
avians involves genes for long feathers being inhibited in the legs by
a unique mechanism.

T. Michael Keesey
Technical Consultant and Developer, Internet Technologies
Glendale, California