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Re: Ah ha! That's where therizinosaurs came from
On 8/14/2011 2:53 PM, Jason Brougham wrote:
Do you feel that simply not needing them explains the pattern? That 19 out
of 67 genera of parrots simply no longer need furculae, while the
remaining genera and all other flying bird families still need them? That
doesn't sound like a very compelling adaptationist argument to me.
I think what the pattern 'means' is this (as the null, barring further
info, especially relative to respective lifestyles w/in parrots
generally) -- NO parrot really needs a furcula, nor do furcula
disadvantage those parrots that have them.
In the case where -- 1) the 'afurculid' condition is distributed
entirely by genera (i.e., no species w/in a 'furculid' genera has lost
the furcula, and no species w/in an afurcilid genera still has them),
but 2) the genera have NOT been constructed using the furcula as a trait
-- then things become more uh, interesting -- and possibly informative
relative to parrot phylogeny -- at least in the (continued) absence of
something in environment that is systematically knocking off those birds
that have furculae.