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Re: A few more...



In a message dated 95-09-29 13:03:00 EDT, Thomas_R_HOLTZ@umail.umd.edu (th81)
writes:

>No, it isn't.  Neotheropoda is a node-based name (the most recent common
>ancestor of Ceratosauria & Tetanurae, and all descendants of that ancestor).
>
>Theropoda is a stem-based name (all taxa sharing a more recent common
>ancestor with birds than with Triceratops).
>
>The dates for the phylogenetic definitions (with regards to priority) are
>1994 for Neotheropoda and 1986 for Theropoda.

Node-based names and stem-based names yield identical clades, because any
node can be the base of only one clade. So, for example, your Neotheropoda as
a stem-based name may be defined as "all taxa sharing a more recent common
ancestor with birds than with herrerasaurians." Which type of definition you
employ is strictly a matter of convenience, perhaps depending on whether you
know just where the root node is or not.