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



IIRC, there was the FUCHSIA hypothesis
Jean-Michel

----- Original Message ----- From: "Erik Boehm" <erikboehm07@yahoo.com>
To: <dinosaur@usc.edu>; <dannj@alphalink.com.au>
Sent: Monday, May 04, 2009 1:53 AM
Subject: RE: Aquatic Origin of birds (was Aquatic spinosaurs (was Size of *Neoceratodus africanus*))





Hmm.... Webbed theropod feet...

That gave me an idea

Many bird feet are webbed today.
Many birds use their wings as flippers...
Pterosaur wings were initially thought to be flippers...
Many birds use their wings to both fly and swim...

With all the discussion about WAIR, trees down/ground up flight, display, etc....

Has anyone suggested bird-like feathers + wings evolved first as flippers?

I'm imagining some little pre-maniraptor Coelosaur swimming around with feathered arm-flippers?
Possibly evolving flight capacity in a way vaguely reminiscent of a flying fish?
Maybe very early takeoffs weren't done by running/leaping from the ground, but rather from the water's surface like a loon?


Could the early long tails with feathers in a horizontal plane conceivably function like a beaver's tail? (Would extensive modification be needed to get a therepod tail to flex up and down with enough force to propel it through the water?) -I'd think it more likely to have a side-side motion if it were for aquatic propulsion, but that doesn't rule out a semi-aquatic origin of birds - they may have only used their flipper wings, and the broad feathering of the tail evolves later for flight?

Could small swimming/aquatic dinosaurs have lead to small flying/volant dinosaurs?

I think small aquatic dino-birds might not fossilize too well, and wouldn't leave much evidence..

Has this been suggested before?


--- On Sun, 5/3/09, Dann Pigdon <dannj@alphalink.com.au> wrote:

From: Dann Pigdon <dannj@alphalink.com.au>
Subject: RE: Aquatic spinosaurs (was Size of *Neoceratodus africanus*)
To: dinosaur@usc.edu
Date: Sunday, May 3, 2009, 3:57 PM
Quoting Christophe Hendrickx <nekarius@hotmail.com>:

> We now have the certainty there were semi-aquatic
dinosaurs, spending mostly their time into
> water, as crocodiles and turtles do
> (http://spinosauridae.fr.gd/Actualit-e2--des-Spinosauridae.htm,
see the abstract "Were some
> dinosaurs aquatic?").
> I know it won't be surprising for some of you but we
have to admit spinosaurids are usually seen
> as terrestrial animals and this was a matter of debate
recently
> 
(http://scienceblogs.com/tetrapodzoology/2009/02/month_in_dinosaurs_part_i.php).

I recall a story many years ago of a webbed theropod track
having been found somewhere along
the coast of Western Australia. I'm sure I've got something
at home about it.

Given the presence of spinosaurs in Africa and South
America, I wouldn't be surprised if they were
present in Australia as well.

--
___________________________________________________________________

Dann Pigdon
GIS / Archaeologist
http://dannsdinosaurs.dyn-o-saur.com
Melbourne, Australia
http://heretichides.game-host.org
___________________________________________________________________










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