Re: NO SECONDARILY FLIGHTLESS THEROPODS

[Ronald Orenstein <ornstn@inforamp.net>]

Matt Troutman writes:

>But, there is a possibilty that they _are_ obliged to. Now among 
>vertebrates that fly, as far as is known, only birds have become 
>flightless. What makes them special in this regard? The answer is rather 
>obvious : birds are an extremely adaptable group of vertebrates that are 
>able of equal locomotion on ground, sea, or air.

Actually, a better answer is that birds have not involved their hind limb
mechanism in the wing structure, and as a result have given up little or
nothing of their ability to get about on the ground.  This makes the loss of
flight comparatively simple in terms of morphological shifts, compared to,
say,
a bat (though the mystacinid bats of New Zealand may have been heading in that
direction).

Soon the animal would start to dive into 
>water and use its wings for underwater and submarine flight as shown by 
>diving petrels. Soon the animal would use its wings only for submarine 
>flight. Essentially the animal would be an underwater flier, not an 
>aerial flier, but essentially the same thing. ( The actual idea of the 
>pseudo-phylogeny was made by Storer but I haven't read that paper yet). 

The auks provide a good example of what such stages might have been like, and
of course they reached flightlessness at least twice (the Great Auk and the
mancallids). 
--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
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