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Re: Re: All those apsids



>>Within Reptilia are two major divisions
>>Thomas R. Holtz, Jr.
>
>Are the euryapsids no longer classified as a monphyletic group?  I see you
>include ichthyosaurs and plesiosaurs among diapsids (placodonts, mesosaurs
>and nothosaurs too, I suppose?).


Mesosaurs may be anapsids, or may be nonreptilian sauropsids (i.e., outside
of the turtle + diapsid clade).  Placodonts, nothosaurs, pachypleurosaurs
(once included in the nothosaurs) and plesiosaurs are a monophyletic group,
to which both Euryapsida and Sauropterygia have been applied.  Ichthyosaurs
are problematic, but show no strong affinity for the sauropterygians.

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