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Re: Turtles and Diverity




Eric,
To what Ronald said, I would add this. If turtles turn out to be Archosauromorphs, it would be a superb example of how a powerful tool (like cladistic analysis) can be a double-edged sword, and must be handled with care (but has enormous potential).
I am a great believer in the overwhelming benefits of cladistic analysis (and it will improve as we refine computer algorithms, etc.). Detractors like Feduccia and Martin tend to exaggerate the occasional failures of cladistic analysis and ignore the many successes.
If turtles are archosauromorphs and anapsids are therefore extinct, that's the way it is (and I would enjoy both the novelty and instructiveness of it). But I will continue to classify them as Order Testudiniformes no matter where they end up, not as an insignicant twig or "offshoot". It is a stable taxonomic module, that I would simply removed from the anapsid clade and plug into the appropriate place in the diapsid clade. Simple as that.
----Cheers, Ken
*******************************************************
From: Ronald Orenstein <ornstn@home.com>
Reply-To: ornstn@home.com
To: ELurio@aol.com, kinman@hotmail.com, dinosaur@usc.edu
Subject: Re: Turtles and Diverity was Re: Classification of Plesiosaurs and Ichthyosaurs?
Date: Fri, 18 May 2001 11:55:49 -0400


At 08:47 AM 18/05/01 -0400, ELurio@aol.com wrote:
WHY?!?!?!?!?! Shouldn't a greater diversity of life living today be far
cooler than greater extinction of forms? Assuming that turtles are anapsids,
isn't that better for the study of life than having them being just a tiny,
insignificant offshoot of the Archosauromorpha like many here are trying to
make birds?

That's "assuming". Some recent studies (which are far from universally accepted) suggest that the anapsid condition in turtles is secondarily derived and their closest relatives may be within Diapsida - I suggest that is what is being referred to here, not a suggestion that all anapsids (eg pareiasaurs) be moved into Archosauromorpha.


-- Ronald I. Orenstein Phone: (905) 820-7886 International Wildlife Coalition Fax/Modem: (905) 569-0116 1825 Shady Creek Court Mississauga, Ontario, Canada L5L 3W2 mailto:ornstn@home.com


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