Landmark paper is finally published

[Ken Kinman]

Dear All,
     A much anticipated paper (on the origins of avian flight) by Ken Dial
was published in the latest issue of Science.  Wing-assisted Incline Running
(WAIR) as early transitional stages has enormous evolutionary implications.
This part of the process would have been "ground up", which would have
eventually been followed by one or more clades developing "trees down"
aerial flight powered ONLY by the wings.  Since WAIR could be considered an
early form of powered flight (sensu lato) in which the legs also contribute
to that "power", the evolution of "powered flight" would have been a much
longer process than predicted by a "trees down" hypothesis alone.
      But it is the cladistic and TAXONOMIC implications that I am even more
excited about.  I would heartily agree with Thomas Holtz that WAIR was
probably practiced by most maniraptoran coelurosaurs (or at least the young
of larger forms), but not practiced by basal coelurosaurs, tyrannosaurs, or
ornithomimosaurs.  If this is confirmed, those forms (capable of WAIR) are
EXACTLY equivalent to my expanded classification of Class Aves (which also
excludes basal coelurosaurs, tyrannosaurs, and ornithomimosaurs).  Do I
detect some hint of consensus building?
     The best synapomorphy of a broadened Class Aves (for which I have been
searching) still seems to lie in the morphology of the shoulder joint
(perhaps in conjunction with aspects of the sternal morphology as well).
Gregory Paul's 2002 book, Dinosaurs of the Air, leans in the same direction,
although some of his secondarily flightless forms could actually turn out to
be primary WAIR forms.  If so, this could end up being one of greatest
challenges (tests) for cladistic analysis and eventually lead to more
sophisticated cladistic analytical techniques.  This process will be messy
and probably heatedly debated, but the WAIR hypothesis could accelerate it
so we will be able to get through that process much more quickly (rather
than being drawn out).
     Whether the WAIR hypothesis is confirmed or not, I still believe Class
AVES should be expanded to include maniraptors, which were well-feathered
"dino-birds" whether they had attained true powered flight (however it is
defined) or not.  Archaeopteryx is just too cladistically labile to provide
a stable anchor, and I certainly don't think most biologists (much less the
public) want Aves restricted to the crown group (which already has a
well-known and suitable name---Neornithes).
           ------ Cheers,
                       Ken Kinman

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