Natural Science Forum / Biology / Paleontology / October 2006

"Recently my paper on this was published; I found that the feather
structure and arrangement indicated that they were used as
lift-generating winglets, and calculated that these structures could
have significantly decreased both the stall speed and turning radius of
the bird. (Longrich, N. 2006. Structure and function of hindlimb
feathers in Archaeopteryx lithographica. Paleobiology
32(3):417-431).The idea of a multi-winged Archaeopteryx has been around
for more than a century, but it hasn't recieved much attention, for
several reasons. First, the feather impressions on the main slab(see
left), which so impressed early workers, were prepared away. Second,
having the Berlin specimen behind the Iron Curtain for decades probably
made it difficult to study. Third, people tend to see what they want or
expect to see. Everybody "knows" that birds don't have four wings so it
became possible to overlook them even when they are in plain sight. I
first studied the Berlin specimen back in 2001 and, if I even noticed
them at all, it never would have occurred to me to examine the hind
limb feathers: I "knew" that the hindlimbs weren't relevant to the
aerodynamics of early birds. It wasn't until the 2003 discovery of the
four-winged dromaeosaurs from China (Microraptor gui and its relatives)
that I was prepared to see what had been right in front of my nose just
a few years before."

http://www.ucalgary.ca/~longrich/archaeopteryx.html

Did Feduccia explode before or after this paper was published?

Ken

I wonder if this indicates that Archaeopteryx wasn't a flapping flyer.
Would the hindlimbs interfere with air being pushed by the downstroke?
Also, a minor error in the paper has Oviraptors included in
Eumaniraptora, which is a node based definition including dromaeosaurs
and birds. But it's a very interesting paper.

The apparent fact that Archaeopteryx hadn't the toe adapted to perching
weakens a bit the trees-down, does not? Or at least ideas that its
ancestors were long-adapted to an primary arboreal lifestyle...

I think that it all makes the most plausible scenario something that is
in between the traditional "birds are modified maniraptorians" and what
I think is Gregory Paul's dromaeossaurs are secondary fligthless, in
which, I think, he supposes that archaeopteryx's ancestors were
arboreal for more time. Part of the connection between this hybrid may
be the WAIR hypothesis

Danniel Soares

In chickens there is a trait called vulture hocks where thigh feathers
resemble small flight feathers instead of normal body feathers at that
location.  This isn't just a rare developmental mess up, but is a breed
characteristic in breeds like Sultans.

Ron Okimoto

What about eagles? They seem to me to have feathers resembling pretty
much those of Archaeopteryx's hindlegs. Do these differ fundamentally
from those that Archaeopteryx? Well, of course I know that eagles do
not use them as apparently is being suggested that Archaeopteryx used,
more or less like those depictions of four winged Microraptor, only
with smaller hindwings; what I am asking is more if couldn't be that
Archae's hindleg wings are so "wings" as are those of eagles, which, as
far as I know (which isn't really far) are not wings at all...

Danniel Soares