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Re: Looking for patterns in extinctions.
What is really pretty interesting is New Zealand. I believe
there's been discussion on this list that it bore fauna similar to those
of late Cretaceous Australia/Antarctica, which it broke away from during
the late Cretaceous. Note, however, that not only did nonavian dinos die
out there, but mammals did as well. Perhaps, of course, they made it
through and perished sometime in the Cenozoic, but that seems unlikely,
seeing how well they've done recently- the introduction of rats, etc.
What NZ does have are tuataras and primitive frogs (geckos, too- did
those raft in or were geckos around in the Late Cretaceous?) which did
survive the K/T boundary in New Zealand. As for ratites, does anybody
have any ideas about whether they became flightless before or after
breaking away? Were they even around 70 million yrs. ago?
At any rate, NZ appears to have had an extinction pattern in many
ways similar to what we seem to see elsewhere- dinosaurs die, lepidosaurs
and amphibians survive, or at least scrape through (again, does anybody
have any ideas about whether ratites are part of NZ's original animal cargo
that broke off of Australia/Antarctica?) - BUT it would seem
that the mammals would NOT have made it through in this case (or again,
they could have bought it in the Cenozoic, but that seems less likely).
This might tend to support the idea that mammals did take quite a
beating coming across the K/T, and that at least in one place on the
globe, were completely wiped out. Blatant speculation: Other areas may have
been depleted by an extinction event as well, but unlike New Zealand, were
open for recolonization.