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RE: Defending grades (Was: Re: Archaeopteryx (rant))

To: grossber@grinnell.edu, Mailing List - Dinosaur <dinosaur@usc.edu>, mightyodinn@yahoo.com
Subject: RE: Defending grades (Was: Re: Archaeopteryx (rant))
From: Ronald Orenstein <ornstn@rogers.com>
Date: Fri, 20 Jun 2003 08:42:33 -0400
In-reply-to: <3EF15664@webmail.grinnell.edu>
Reply-to: ornstn@rogers.com
Sender: owner-dinosaur@usc.edu

At 11:19 PM 19/06/03 -0500, grossber wrote:

While ancestral reptiles are also ancestral to aves, we should maintain this distinction. Why? Because by placing them in the clade of reptiles, we would have to do the same for mammals

Actually, not so according to modern cladistic views which place the synapsid-mammal line as a sister-group to the reptile-bird line. Thus mammals are synapsids, amniotes and tetrapods, but not reptiles (Neither are "mammal-like reptiles").

-- 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@rogers.com

References:
- RE: Defending grades (Was: Re: Archaeopteryx (rant))
  - From: grossber <grossber@grinnell.edu>

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