FUCHSIA and the Ostrom Symposium Volume (long...)

["David Marjanovic" <david.marjanovic@gmx.at>]

I think that the, as I hope, logical sequence below supports FUCHSIA over
all proposed alternatives. It is probably biased, in that my main thought in
writing this was "is that stuff in any way compatible with FUCHSIA", but
judge yourselves:

Phillip Burgers & Kevin Padian: Why thrust and ground effect are more
important than lift in the evolution of sustained flight, 351 -- 361 in
Jacques Gauthier & Lawrence F. Gall (eds): New Perspectives on the Origin
and Early Evolution of Birds. Proceedings of the International Symposium in
Honor of John H. Ostrom, Yale Peabody Museum 2001

+ Shows that once wings and musculature sufficient for powered flight are
present, takeoff from the ground is feasible, so if these features were
present before flight, as FUCHSIA incl. HOBHY assumes, an arboreal phase is
not needed.
(+ Explains what well-curved claws are good for in a terrestrial runner that
doesn't climb -- to retain a grip on the ground when that unwanted byproduct
called lift becomes too strong.)
+ Shows that sustained flight (cursorial, FUCHSIA) and nonsustained flight
(parachuting, gliding) can't have both been used while powered flight
originated.
- Fails to show (actually doesn't even attempt) why a sane winged runner
would suddenly begin to flap its wings at maximum speed. Why would anyone do
that, without knowing a priori that doing so increases speed and/or leads to
takeoff? Roadrunners don't do it when they just run. Chickens are, if I
don't misinterpret it, mentioned as doing so, but I think they're just
trying to take off.

=> Fits FUCHSIA because thrust is a good idea underwater while lift usually
isn't, especially at low body densities. The ability to take off from
running would then evolve in an animal that can already fly, and the first
takeoffs into the air would have been simply flying out of the water.

Jeremy M. V. Rayner: On the origin and evolution of flapping flight
aerodynamics in birds, 363 -- 385

(- Uses great confidence in an outdated phylogeny to show that bats must
have begun as gliders.)

+ Interesting quote (p. 380):

"_Alternative paradigms for flight evolution_
Debate about avian flight evolution has rarely extricated itself from the
polarized cursorial or arboreal models, or from compromises of the type
raised here. An alternative biomechanical model for the origin of flight has
been put forward recently by Eberl[*] (1996); this is similar to a
hypothesis I advanced -- in part in jest -- some while before (Rayner
1985d). This idea, that flight evolved underwater, is consistent with the
taphonomy of *Archaeopteryx* in the shallow lagoonal environment of
Solnhofen, and also with speculation of a piscivorous diet. It is also an
attractive idea for mechanical reasons, since the density of water is
sufficently high to support most of an animal's weight by buoyancy. Several
other lineages of tetrapods that have secondarily become obligate swimmers
have evolved similar swimming mechanisms using the forelimbs as wings, and
effectively flying underwater (ichthyosaurs [what?], plesiosaurs [hindlimbs,
too], marine turtles, sea lions[, rays]). This adaptation is a particularly
effective form of locootion, and all of these groups are particularly
efficient swimmers [really?]. It has also evolved independently in several
avian groups; some have become secondarily flightless (penguins, some ducks
and some alcids), while others can fly in both water and air (some ducks,
diving petrels, morid gannets, some alcids, and dippers). Evidently this
swimming mode presents rather few mechanical or morphological obstacles.
        Unfortunately, this model cannot explain avian evolution [?], and
the evidence against it comes from the morphology of *Archaeopteryx*. All
wing-propelled underwater fliers among birds have unusually large
supracoracoideus muscles to elevate the wing during the upstroke (Rayner
1988b). Yet *Archaeopteryx* had no supracoracoideus (Ostrom 1976b; see
above), and there is no evodence of another wing elevator muscle."

Why shouldn't Archie have had a deltoideus? And when nonavian underwater
fliers don't have a supracoracoideus, why should *Archie*, more basal than
any bird with a well-developed supracoracoideus, have had one?

"Although insubstantial [a quick dismissal...], this brief digression is
informative. The origin of flight may have followed a pathway appreciably
distant from those normally envisaged, or discussed here. Both cursorial and
arboreal models, as normally formulated, raise significant difficulties that
have yet to be resolved. A combination of unusual, or possibly rapidly
changing, environmental conditions [coupled with the inability to flee!] may
be responsible, and this may make such hypotheses resistant to physical
modeling of the kinds reviewed here."

:-)

* Sic. While that paper itself spells him Ebel on all occasions, I don't
know if that name exists, while with r it does. On the other hand, I can't
imagine such a series of typos (either way). I'll ask Rayner whose e-mail
address is kindly supplied in the book.

James A. Hopson: Ecomorphology of avian and nonavian theropod phalangeal
proportions: Implications for the arboreal versus terrestrial origin of bird
flight, 211 -- 235

+ This study was needed. It shows that pedal phalangeal proportions have
more to do with ecology than with phylogeny. It includes dippers...
terrestrial, and about as much, maybe slightly more so, than
*Archaeopteryx*, which itself is just on the terrestrial side of the
boundary and borders *Confuciusornis* which occupies almost the entire
narrow overlap between terrestrial and arboreal birds. An interesting
result, considering that dippers don't only fly underwater but also walk
around there, firmly gripping stones, to save energy in the fight against
their ludicrously low (passerine) density. -- Therefore their phalangeal
proportions don't exclude a similar lifestyle for *Archaeopteryx*. Hoatzins
plot more arboreal than *Confuciusornis*.

Alan D. Gishlick: The function of the manus and forelimb of *Deinonychus
antirrhopus* and its importance for the origin of avian flight, 301 -- 318

+ Shows that the predatory stroke would not be hindered by the presence of
wing feathers,
+ is _very_ similar to the flight stroke,
- except for its direction... forward instead of downward. I don't know how
correct the glenoid orientation that Gishlick assumes is, and he doesn't
write much about it. A runner that, in the style of Burgers & Padian above,
tried to flap wings in the predatory stroke while running would have a very
effective brake. :-)

=> Leaves me room to speculate that the predatory stroke was modified for
moving underwater where almost every movement moves the body so that
locomotion can evolve slowly toward the threshold needed for flight in air.

Kevin Padian: Stages in the origin of flight: Beyond the arboreal-cursorial
dichotomy, 255 -- 272

Pronounces this on p. 266: "but this is a somewhat different motion than the
flight stroke". :-)

Okay. Finished for now. Now take out your *Allosaurus* jaws and hacksaw it
apart. :-)