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Re: Phyl tax misunderstandings



At 01:02 PM 11/14/97 -0500, Norm King wrote:
>Tom Holtz said (11/14/97; 1:43p):
>
>(out of context)
>
>>Or, there will always be a clade (Maniraptora) comprised of birds 
>>and all taxa sharing a more recent ancestor with birds than with
>>Ornithomimidae.
>
>As I have ranted before, you cannot DEFINE this evolutionary path into 
>existence.

You have ranted this before.  This time, please read what the words actually
say, not what you seem to be thinking they say.

>I believe that is an hypothesis that has not yet been 
>"proved."  Just ask George Olshevsky or Alan Feduccia whether that clade 
>will always exist.

To my knowledge, neither George nor Alan are creationists.  Accepting that
evolution is real, George and Alan accept that there is a clade comprised on
(to be clearer here) all modern birds and all taxa closer to it than to
Ornithomimidae.  In George's cladogram, this would not be dramatically
different than (for example) a Gauthier- or Holtz-style composition of
"Maniraptora": where we differ is closer to the base of the tree.

In Alan's "cladogram" (never published as such) the clade of taxa containing
birds and all taxa closer to birds would exclude the typical non-avian
dinosaurs.  It would include things like Longisquama and Megalancosaurus.
It might even include crocodilians.  However, that clade would still be there.

Unless you accept either birds or ornithomimids as aliens or as specially
created, there will ALWAYS be a clade comprised of birds and closer and of
ornithomimids or close.

I hope that this is even clearer this time.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661