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On 9/24/06, Robert J. Schenck <email@example.com> wrote:
Per Mr. Cowen
"Meanwhile, we should go with as uniformitarian
an interpretation as possible: and that says that
Archaeopteryx was NOT four-winged."
Why is that more uniformitarian, if there are
primitive bird-ancestors with 4 wings, then the 4
winged condition would be the standard no?
Microraptorians (assuming that's what you're referring to) are not
"primitive bird ancestors", since they postdate _Archaeopteryx_ and
are contemporaneous with many types of pygostylian bird. This
perception is an unfortunate side-effect of the "modern bird-centric"
view of theropodan evolution, where "modern bird-like" = "derived".
The null hypothesis should be that microraptorians are *more* derived
(i.e., more different from the final common ancestor) than
_Archaeopteryx_, since they existed 20-odd million years later.
Perhaps _Archaeopteryx_ represents the basal condition and
microraptorians emphasized the hindlimbs' role while pygostylians
And then there was the case of the 4-legged
Wow. I think I used to have an action figure that looked like a
grown-up version of that.
T. Michael Keesey
The Dinosauricon: http://dino.lm.com
Parry & Carney: http://parryandcarney.com