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PhyloCode was Re: Cladistic definitions of Dinosauria, Saurischia, Sauropodomorpha



----- Original Message -----
From: "Phil Bigelow" <bigelowp@juno.com>
Sent: Monday, September 19, 2005 5:25 PM

And to be clear:  I *loath* the idea of "redefining" a clade, and I hope
that Phylocode comes up with rules that roughly parallel the rules for
gen. sp. naming in the ICZN.

See below.

Once a clade has been defined in the
literature, it remains that way forever (unless it has broken some other
naming rule, such as priority, preoccupation, etc., etc.).

Example: If Padian and May's (1993) definition is ever formerly adopted,
and if birds are later found to be outside of Dinosauria, then I would
advocate just leaving Padian and May's clade name in place, and then
creating a new clade that excludes birds.  Call it Eudinosauria, or
Owendinosauria, or something similar.

You'd lose a lot of people in that case.

But I would only advocate such a thing provided that all of the following
criteria are rigorously met:

1) Artiodactyla is indeed monophyletic.

What degree of certainty would you like...?

3) The empirical evidence for cetaceans being members of Ariodactyla must
be *overwhelming* (such as is the case with birds being dinosaurs).

Where to draw the line?

The line-drawing problem is less difficult if we just leave Recommendation 11A as it is. (Though... IMHO several definitions proposed by famous supporters of the PhyloCode violate its first sentence...)

Just for the record, I suspect  that the final version of Phylocode will
require that a clade definition that uses a Linnaean name *must* use as
specifiers only traditional members of that Linnaean group (you appear to
believe this too).

Please, please, please! Don't "hope" or "suspect". Instead read -- and participate!


The Phylocode is here http://www.ohiou.edu/phylocode. When I say "read", I'm serious -- it's a _much_ shorter _and_ more legible document than the ICZN!

The bottom of the PhyloCode homepage gives the instructions for joining the (traffic-poor) mailing list, and for joining the INSP (which is almost the same as the mailing list). The International Society for Phylogenetic Nomenclature is neither the European Commission nor the US Supreme Court!!!