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Re: Aquatic Origin of birds (was Aquatic spinosaurs (was Size of *Neoceratodus africanus*))



> With all the discussion about WAIR, trees down/ground up flight, display, 
> etc....
>
> Has anyone suggested bird-like feathers + wings evolved first as flippers?


Horatio Hackett Newman proposed an aquatic origin for flight in the
1920 textbook Vertebrate Zoology
(http://books.google.com/books?dq=Horatio+Hackett+Newman+%2B+zoology&pg=PA276&id=iDUuAAAAYAAJ&as_brr=1#PPA275,M1)
. In the section on birds there is a subsection called "Diving Origin
of Flight" which reads;

"So far as the writer is aware, no one has proposed a theory of flight
involving the idea that flight may have originated in connection with
soaring over the water and diving after fish. Yet there are certain
considerations that strongly support such a conception. According to
this view the pro-aves used the fore limbs, together with their
membranes and elongated scales (possibly also the similar structures
of the legs), as planes to aid in diving. The value of such
accessories is obvious; the dive being more definitely directed, the
descent being made flatter so as to carry the diver farther out from
shore, and the force of the plunge being eased up sufficiently to
avoid shock. If the wings were flapped more or less a longer glide out
over the water could be made, and possible circling movements could be
made over the water while searching for fish. It would appear
therefore that the use of the pro-wings as planes in diving would
serve as useful a function as in running or leaping from bough to
bough.

We would then have to suppose that some of the archaic diving birds,
such as the penguins, underwent a specialization of the primitive
wings, using them for under-water "flying"; that others, such as the
grebes, never developed them into fully effective organs of flight;
while still others, such as the loons, became good flyers though still
retaining their diving propensities. According to Dr. Coues, the loon
practically flies under the water, using the wings as well as the feet
as propellers. The strong flying sea-birds would then be derived from
ancestral diving types that had gradually perfected their flight;
while land-birds of all sorts would be derivatives of the sea-birds.
There are, in fact, many evidences that the sea is the ancestral home
of the birds and that they have invaded the land in comparatively
recent times. If one turns to page 289, where the orders of carinate
birds are listed, he will note that Brigade I (largely archaic birds)
consist almost entirely of water birds, while Brigade II (largely
modern types) consists exclusively of land birds, with the arboreal
birds confined to the more highly specialized sub-orders. If this
classification represents an approximation to the phylogenetic order,
the arboreal birds, instead of being the most primitive (as the theory
of arboreal origin of flight maintains), are a modern product, and
life in the trees is a modern habit.

Archaeopteryx, of course, seems to militate against the diving origin
of flight, for it is assumed to be a climbing arboreal bird. But might
not climbing be equally appropriate as an aid in scaling cliffs after
diving and swimming in the water? Moreover, the teeth of Archaeopteryx
would be of great service in seizing fish. On the whole, then, the
existence of Archaeopteryx is no more a barrier to the acceptance of
the diving than to the cursorial origin of flight; while other
considerations appear to make the former more probable than the
latter."

Best regards,

Brian
http://scienceblogs.com/laelaps/
http://dinosaur.smithsonianmag.com/