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Re: Unnamed groups



>Hello,
>        I asked this a few days ago and have recieved no answers so am
>re-asking. What is an "unnamed group". There are many on the cladograms in
>The Dinosauria with descriptions of them but no reason as to why they are
>unnamed. Are they just suposition, unpublished or disputed? Thanks in advance.

Unnamed groups are, in a way, a reaction to the standard practice of the
early-to-mid 1980s, when every node was named (for examples, Sereno's
Ornithischia cladogram or McKenna's various Mammalia cladograms).

Since then, names are recommended for monophyletic groups joining, for
example, two major subclades, or for very well corroborated clades, or for
major stems.  Other nodes which are the formed by the joining of one genus or
so to the stem, or those which are only weakly  corroborated, are often left
unnamed.

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