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Re: Aw: Re: Microraptor also ate fish

Rescued from truncation:

Scott Selberg <ssselberg@hotmail.com> wrote:

> Maybe I'm missing something. If there is one thing we know about
> Microraptor, it is that it had large, aerodynamic wings-- four of them.
> Don't we all agree that they evolved because it spent enough time in the
> air to have been of use? That this type of wing equals air travel? Since
> no one seems to think these creatures could launch themselves into
> powered flight from the ground, how the heck did they get into the air?
> Isn't that where trees come in?

The function of the wings in Microraptor is still quite contentious.  It
is generally agreed that they were probably aerodynamically active, but
this does not mean they were used for sustained flight.  In other words,
no, those four wings do not equal air travel.

Our group (Habib, Hall, Hone, Chiappe) argues that the hind wings
provided control authority, rather than weight support - this would be
applicable in a wide range of locomotion scenarios.  The forewings could
provide weight support for extended aerial phases, but there are plenty
of other things an animal can do with lift and drag than glide around.
Kevin Padian and Ken Dial have a slightly different model, but it also
supports more of a control authority role for the hind wings and even
less aerial locomotion than we suggest.

Powered flight capacity is also contentious for Microraptor; it isn't
entirely clear that powered flight is out of the question for it.
Furthermore, perch launching and ground launching turn out to be very
similar, so the arboreal hypotheses don't gain as much ground in that
respect as is often supposed (both are initiated by leaping - nothing
falls out of the tree to take off).  Basically, the idea that trees are
fundamental for a weak flyer to get into the air is based on intuitive
notions of flight, rather than the real data.  This was the subject of
my recently submitted SVP Abstract.  Here's hoping I get to present on
it come the Fall.


--Mike H.

Michael Habib
Assistant Professor of Cell and Neurobiology
Keck School of Medicine of USC
University of Southern California
Bishop Research Building; Room 403
1333 San Pablo Street, Los Angeles 90089-9112
(443) 280-0181