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Age of Early Birds
>>Evolution thrives on diversity. We have seven or eight specimens of
>>_Archaeopteryx_ as the _entire_ fossil record of volant aviforms for the
>>_entire_ Jurassic period. I suspect we're missing a few!
>Ignorant question: I thought that Confuciusornis (and Sinornis and a few
>others) were late Jurassic. Am I wrong?
Sinornis has always been correctly assinged to the Early Cretaceous.
If the radiometric dates that Martin and co. used for Confuciusornis are
correct, then (despite their text) it is Early Cretaceous. The use the 135
Ma date for the J-K boundary (taken off of a poster!), but most recent
chronologies have that boundary at 145. In fact, this suggests that
Confuciusornis is more than 10, and closer to 15 million years younger than
Archaeopteryx. And, as the evolution of whales has shown, a LOT can happen
in 10-15 million years...
Thomas R. Holtz, Jr.
Dept. of Geology
University of Maryland
College Park, MD 20742