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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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