Re: Dromornithids and size limits.

[Vorompatra@aol.com]

In a message dated 4/12/04 11:34:16 PM Eastern Daylight Time, 
qilongia@yahoo.com writes:

<< Birds are tetrapods, as a tetrapod is not defined by having four 
TERRESTRIAL limbs. >>

Jaime, I think Eric meant to use "quadruped" here, vice "tetrapod" since I 
don't think he was talking about it in the taxonomic sense. I'm guessing most 
of 
us know that birds are tetrapods too, except literally (i.e., "four-footed").

As I understand it, his argument is that birds have gone too far down an 
evolutionary path, with forelimbs that are probably too specialized to 
"devolve" 
into potentially-manipulative appendages (in the case of the Moa, the wing had 
disappeared completely, bone and all). Perhaps the same can be said of some 
mammals (e.g., cetaceans, sirenians), but I suspect even bats retain enough of 
the forelimb structure that they could, given the right conditions, evolve 
hands out of their wings.

Chip Howell
www.geocities.com/Vorompatra/index.html