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Re: Re: Egg-types and Taxonomy?



>In a message dated 95-10-23 18:02:23 EDT, Stang1996@aol.com writes:
>
>>The D.-P. eggs are only found a few ornithopods though, most of 
>>them have D.-S. eggs.  My point was though, that in the 
>>monophyletic saurischia arrangement one would expect more 
>>similarities (some similarities) between sauropods and theropods' 
>>eggs; rather than between sauropods and ornithischians' eggs.  In 
>>other words: why would a group have more in common with its 
>>outgroup rather than its sister taxon?
>
>Much hinges on whether the eggs have been properly identified as sauropod,
>ornithischian, theropod, etc. But it is nice to see sauropods grouping with
>ornithischians anyway (as Phytodinosauria). That's the way I would expect it.
>
Unless the D.S. eggs are shown to be a derived feature, they do not support
a monophyletic Phytodinosauria anymore than the support a monophyletic
Saurischia.  After all, crocodilians share more features with lizards than
with birds.  However, the features they share with lizards are primtive
characters, while the few they share with birds are derived characters.

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