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Re: Dilophosaurus



On Tue, Aug 30, 2011 at 11:24 AM, Augusto Haro <augustoharo@gmail.com> wrote:
> What I like of the definitions of Avepoda and some other Paulian names
> in "Dinosaurs of the Air" (2002) is the use of of
> apomorphy+clade-based taxon names. As long as the problem of
> apomorphy-based names was the possibility of convergence (and to what
> clade acquiring the feature the name goes), this was explicitly
> prevented in apomorphy+clade-based names. These seem to have great
> use, overall if the clade used is a LITU (is it right to call "clade"
> to a leaf?).

Clades can be terminal, yes. A clade is just an ancestor and all of
its descendants. If a taxonomic unit has no descendants, then it is
itself a clade.

> I would like to know from those among you with better
> knowledge of the Phylocode what does it say about this practice.

The PhyloCode places no restriction on types of phylogenetic
definition. Apomorphy-based definitions have always been one of the
prescribed types of phylogenetic definition. See Note 9.3.1:
http://www.ohio.edu/phylocode/art9.html#note9.3.1

The PhyloCode *does* place restrictions on what may be used as a
specifier (see Art. 11: http://www.ohio.edu/phylocode/art11.html ).
Specifiers must be apomorphies, specimens, or species, and at least
one specifier in a definition must be a specimen or species. Per Note
11.1.1, use of a species as a specifier implicitly indicates the type
specimen (if there is one).

So, IIRC, the definitions in Dinosaurs of the Air are very close to
PhyloCode-ready; they'd just need species or specimens to be used
instead of clades.
-- 
T. Michael Keesey
http://tmkeesey.net/