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Re: The birds vs. the pterosaurs

At 07:07 PM 05/02/01 +0000, Matthew Bonnan wrote:
Steve continues:
"Perhaps they went extinct later,long after the mass extinction occured, because they were aced out by the birds. Perhaps the birds made the old flying archosaurs obsolete.

While it may be true, in the end, that birds out-competed pterosaurs, we should remember that they existed side-by-side for tens of millions of years. Also, we have no idea (other than guesswork) of the extent to which they overlapped ecologically. Birds and bats coexist today, and some have suggested that this may be primarily because bats are, generally, nocturnal whereas relatively few birds are. Both birds and pterosaurs were quite diverse in the Mesozoic, probably more than we realize because of the scarcity of their fossils. Rather than birds eliminating pterosaurs across the board, it seems more likely that, in some situations, birds prevailed while in others they did not. It is, perhaps, instructive that the latest known pterosaurs were much larger than any known bird; possibly something about their internal architecture a them better adapted to large size, so that the role of the giant flyer became uniquely their own.

>Maybe birds had different reproductive strategies than pterosaurs which, by chance, allowed them to survive the K/T event.

Is it actually known whether any pterosaurs even made it as far as the K/T? Am I not correct that at least one line, the rhamphorhynchoids, did not even survive the Jurassic, and that the group's diversity diminished towards the end of the Cretaceous?

"Perhaps, like the corvids of today, the pterosaurs didn't change much physically over the years, but instead "chose evolutionarily" to "work on their brains", ie, they adapted mainly by getting smarter. ) By the mid cretaceous, I believe the pterosaurs were the smartest thing on the planet. You can correct me if I'm mistaken."

There is absolutely no way to determine this, of course, although I have never heard that their brains were particularly large (though I assume they have large optic lobes, and would certainly needed pretty good higher brain functions to control the mechanics of flight. That certainly isn't the same as intelligence, though.

Ronald I. Orenstein Phone: (905) 820-7886
International Wildlife Coalition Fax/Modem: (905) 569-0116
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