[Taxacom] Phylocode vs Linnean nomenclature, again.

[Curtis Clark]

> FYI, a debate at Yale this very afternoon!(The newspaper article below was brought to my attention by a sharp-eyed Commissioner, but strangely it wasn't advertised on Taxacom or the ICZN listservers ;-)  It might be fun to have a first-hand report, if any Taxacomers happen to be attending.
>
People will use the names that are useful in the work they do, and if 
those names don't exist, they will create them.

Linnaean naming, as practiced in the latter part of the 20th C, had two 
issues that made it difficult for phylogeneticists to use. First, 
paraphyletic taxa cannot coexist with monphyletic taxa that cross grade 
boundaries: there will never be a Linnaean taxon name for the clade 
Dinosauria in any system that includes Reptilia (Ken Kinman 
notwithstanding, because his system has never caught on).

Second, ranking has both enomous advantages and enormous disadvantages: 
the former by estabishing the topology of a hierarchy without requiring 
a detailed knowledge of its members, and the latter from the difficulty 
of making changes to a hierarchy that change ranks, because in Linnaean 
nomenclature, that almost always means a change of name.

In an alternate universe, biologists and texbook authors would have 
rapidly adopted clade-based taxa, there would have been a spurt of 
renaming, and the Linnaean system would have been intact. But that 
didn't happen, for two reasons. First, phylogenetics didn't catch on as 
fast as its proponents would have liked, and there are a number of 
people (perhaps all on this list) who still reject it. Second, molecular 
studies helped solve some known taxonomic conundrums (e.g., the 
heterogeneous nature of the Scrophulariaceae in the flowering plants) 
and exposed other unknown issues, all of which led to the need for 
multiple name changes.

Phylocode arose from that. Some Phylocoders I've talked to felt that 
named clades would always be second-class citizens in Linnaean 
nomenclature, so they saw the only solution to be a new code. If there's 
any "blame" for Phylocode, it can be found in the attitudes of 
taxonomists who want to preserve grade-based, heterogeneous taxa.

The use of unranked clade names in Linnaean taxonomies is an alternative 
(and one that I support over Phylocode), but *clades will be named*.

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Curtis Clark
Cal Poly Pomona