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Re: Protopenguins and pterosaurs
Thanks for finding this for us!
The fossils of penguins were dated by the geologic layer they were found in.
The New Zealand Waipara Greensand, a Paleocene (early Tertiary) formation
just above a well known Cretaceous/ Tertiary boundary site.
They state that the fossils, a new genus (Waimanu) provide a lower estimate
of 61-62 Ma for teh divergence of penguins and other birds. They think
that that estabilshes a reliable calibration point for avian evolution, and
conclude after alot of mathematical juggling and DNA sequences that modern
crown group birds must have radiated in the late Cretaceous.
They provide an anatomatical analysis of their ancient penguin species and
their place in cladistics that I'll let y'all figure out - I'm not
Next they consider genetic relationships between the various clades of
modern birds, and estimate when they diverged. The correctness of that
analysis would depend on how clades of modern birds are really related to
each other; that is very controversial.
However, you do have to grant that it takes a certain amount of time for so
much genetic mutation to take place. The weakest part of their article as
far as I'm concerned is taht they really don't go into detail on how long it
took for the assorted species to diverge.
I would, however, be startled if, no matter when penguins evolved relative
to other birds, it didn't take more than three million years for them to
evolve from Basal Bird. After all, humans diverged from chimpanzees a
couple of million years ago!
Ancient DNA. LOL! Lately I 've caught even CNN making hysterical errors
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Subject: Protopenguins and pterosaurs
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