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Re: Egg-types and Taxonomy?
>I've been looking through "Dinosaur Eggs and Babies," and hev come across
>Figure 10.2. This shows the basic types of dinosaur eggs and what groups
>that they've been atributed to. There are basically three types of Dinosaur
>eggs: Dinosauroid-spherulitic, Dinosauroid- prismatic, and Ornithoid. The
>D.-S. eggs have been atributed to Sauropods and Ornithischians, the D.-P.
>eggs to some ornithopods and marginocephalans, and the ornithoid eggs to
>theropods and birds (duh). Anyways... I was thinking, if saurischia really
>was monophyletic, shouldn't sauropod eggs be in a group be themselves,
>different from the theropods' and ornithischians' eggs? But on the other
>hand... if phytodinosauria was monophyletic shouldn't sauropod and
>ornithischians be more similar to eachother than they are to theropod's
>(which they are)?
If the D.S. egg was the primitive dinosaur condition, the ornithoid a
derived theropod condition, and the D.P. a derived cerapod (ornithopod +
marginocephalian) condition, you would get the patter seen above. After
all, for every character, there is a primitive state. Anyone know what is the
condition in dinosaur outgroups?
Thomas R. Holtz, Jr.
Dept. of Geology
University of Maryland
College Park, MD 20742