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Re: Re: A few more...



>In a message dated 95-09-28 13:58:31 EDT, Thomas_R_HOLTZ@umail.umd.edu (th81)
>writes:
>
>>Actually, Gauthier already defined "Saurischia" as birds and all dinos
>>closer to birds than to Ornithischia, and "Theropoda" as birds and all dinos
>>closer to birds than to Sauropodomorpha.  Padian & May defined
>>"Ornithischia" as Triceratops and all dinos closer to Trike than to birds.
>
>I love these ad hoc definitions. Suppose there were no dinos closer to birds
>than to Ornithischia, which would be the case if brontosaurs were basal to
>Ornithschia instead of Theropoda, a possibility certainly not excluded by any
>known cladistic analysis. And defining Theropoda as birds and all dinos

Actually, it is is excluded in Gauthier 1986.

>closer to birds than to Sauropodomorpha could well place lagosuchians and
>herrerasaurians within Theropoda (doesn't bother me, by the way), since
>there's no way any known lagosuchian or herrerasaurian was ancestral to any
>brontosaur unless they magically regained pedal digit V. Likewise, the

Much in the way that the hoatzin "magically regained" functional unguals?

Reversals happen.

>definition of Ornithischia as all dinos closer to _Triceratops_ than to birds
>does not exclude brontosaurs from Ornithischia.

Yep.  If Sauropodamorpha or some component thereof does turn out to be
closer to Trike than to birds, than those critters would be Ornithischians.
If this were the case, "Predentata" might be a good name for the
Lesothosaurus+Trike node.

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