[Taxacom] PhyloCode & ICZN to "duke it out"?

Richard Pyle deepreef at bishopmuseum.org
Thu Oct 4 15:35:48 CDT 2007

> I can understand the point that the two systems were devised 
> to deal with two different issues, and may have their own 
> merits when dealing with these respective issues. What I 
> can't understand however is the suggestion that the two 
> systems could ever coexist. If we have to live with two 
> systems acting on the same single set of names, each with a 
> different set of rules, we will be in the worst possible 
> situation in terms of communicating anything.

Yes, this is often cited as a reason why Phylocode is a terrible thing (or,
conversely, why the Linnaean system will be a terrible thing once Phylocode
names start catching on).  I'm just not too worried about it.

First of all, I suspect that only professional taxonomists will even be
aware there are two systems, and they will (in most cases) be smart enough
to read the "Methods" section of any given article to see which system the
included names are governed by.

Second, the overwhelming emphasis of Linnaean nomenclature is focused at the
species level, and Phylocode explicitly excludes species names (Art 21.1 --
http://www.ohiou.edu/phylocode/art21.html). I suspect most usage of
phylocode names will be for taxa traditionally treated at ranks above the
Family level, which means that for Zoology at least, there will be no
overlap in terms of historical usages of names.

Third, even in cases where there is overlap, the Phylocode name-usages can
be thought of just like any other taxon-concept usage of a Linnaean-based
name, because when the Phylocode adopts pre-existing names for
genera/families/etc. under existing Codes, there is a requirement that the
type species/specimen be included among the specifiers of the Phylocode
version of the name (Art 11.7 -- http://www.ohiou.edu/phylocode/art11.html).
(Note to Phylocode authors: this should be extended to include type genus of
pre-existing family-rank names -- and perhaps higher for
botanical/bacteriological names). Thus, the only difference between a
Phylocode usage of a name and a traditional usage of the corresponding name
is that the Phylocode usage will have a more explicit definition of the
intended taxonomic concept in that usage, compared to most traditional
usages of Linnaean names.  In other words, it should be (and probably
eventually will be, if the Phylocode survives) the Phylocoders who will have
a legitimate complaint against the traditional users of shared names for
being so damn ambiguous (in many cases) about the intended scope of the
taxon concept associated with the name.

Fourth, we already have multiple name systems in effect (i.e., vernacular
names), and somehow we manage to survive.  Granted, vernacular names are
usually very easy to spot as such (not italicized, not Latinized, etc.), and
I have long recommended that the Phylocoders do something to inherently
disambiguate their names (something that will be increasingly easy to do as
more and more literature is published electronically, allowing names to be
internally marked-up and tagged with embedded metadata and hyperlinks.  I
haven't' re-read the entire v.4 of Phylocode, so maybe there are provisions
in there already.

There are other reasons I'm not worried about it, but I'm a little foggy
after a short night of sleep, so I'll leave it there for now.

> Currently, more and more Linnean names are being "converted" 
> to clades by giving them a phylogenetic definition - 
> typically a definition that attempts to make the content of 
> the clade the same as the most widely accepted content of the 
> Linnean taxon. The basic problem is, this equivalence of 
> contents will in many cases not survive the phylogenetic 
> hypotheses under which these definitions were proposed.

There is NO content definition for Linnaean names under the existing Codes.
In fact, this is probably the main reason why the authors of the Phylocode
felt a need for a new system in the first place (that, plus the ranks
problem when mapping nomenclatural hierarchy to clades).  Linnaean names are
anchored to a single "type", and thus have no defined scope of content.  As
I alluded to above, one way of looking at Phylocode names that are re-used
pre-existing Linnaean names is that they are exactly the same thing except
more-precisely defined in terms of the intended taxon concept.  If only 250
years of Linnaean name usage history had done a much!  Note that "taxon
concept" is not the same thing as "clade".  It's just that Phylocoders will
choose to use clades as a way of scoping taxon concepts (as most traditional
taxonomist generally do anyway, whether or not they are themselves
cladists); whereas as some (but evidently not all) traditional taxonomists
will allow their taxon concepts a little more latitude for scoping in some

> Imagine, e.g., that an internal specifier of a "converted" 
> family name is found to belong to a rather distant family. 
> Everybody agrees on this, and there are no particular 
> lumper/splitter problems. However :
> - As per PhyloCode rules, the "converted" name then makes a 
> big jump upwards, and ends up covering a larger clade 
> equivalent to, say, a suborder; we now need to devise a new 
> name if we still want to refer to the clade made of the 
> former family minus this specifier.

I'm not sure I understand how this is different from subjective synonymy for
Linnaean nomenclature (other than the rank thing, which is not relevant in
the context of Phylocode nomenclature anyway).  Maybe my tired brain is
missing something fundamental here. Perhaps you're worried about reversal of
hierarchy of pre-existing names?  I haven't thought this through entirely,
so there may well be a concern that I'm missing here.  But I guess it would
depend on how often the problem came up.

> - As per IC*N rules, unless that specifier is the type of the 
> family, it is simply transferred to the family where it 
> belongs; 

See my recommendation above for Phylocode to extend Art 11.7 to at least the
realm of pre-existing family names, if not higher for Codes that govern the
higher names.

> the same name continues to apply to the family minus 
> this specifier - a new, more recent name can in no case 
> become its valid name. (With a bit of bad luck, it's the name 
> of the family to which the specifier is transferred, that could end up
> changed.)

Fair enough -- but Linnaean nomenclature is not without its own fair share
of "bad luck" already.

> These two systems are fundamentally incompatible. Either one 
> must be chosen and the other abandoned altogether; or at the 
> very least it would have to be decided that they regulate two 
> entirely distinct sets of names. Any other option would 
> unavoidably produce nomenclatural chaos.

You may be right, and I may be overly relaxed about it. But as I sit here in
my chair...err...seat, typing on the keyboard of my
laptop...err...notebook...err...personal computer, and I contemplate the
existing problems of "homography" (homonymy across different Linnaean Codes)
and such...I am reminded that the human brain seems to manage reasonably
well in the face of homonymy & synonymy.  Sure, it would be a lot easier if
there was only one universal language spoken by all the peoples of the word
-- but the fact that there is an existing diversity of language has not
caused chaos (well -- at least not enough that governments are trying to
establish a universal language for all humankind).  Yes, it would be less
confusing if pharmaceutical companies did not define both a brand name and a
generic name for their drugs (Motrin/Ibuprofen), but they have very specific
reasons for doing so -- just as I 

The ultimate answer to this issue boils down what will lead to more
effective communication in the long run.  There is a legitimate argument
that Linnaean nomenclature is poorly designed as a tool to communicate
phylogeny, and hence there is a need for a new communication tool.  There is
also a legitimate argument that having two systems of nomenclature will lead
to confusion and chaos, causing a larger problem of communication than the
problem that the second system was intended to solve.  None of us can know
for sure where the path towards improved communication lies.  The scary part
is the damage that might be done if the new system proves to cause more
problems than it solves.

By the way, I've said this many times before, and I will say it again:  I am
*NOT* a cheerleader for the Phylocode (my pom-poms lie dormant).  I am
almost certain that I would never make use of Phylocode names myself,
because I find the current practice of phylogenetic speculation
intellectually unsatisfying (ouch -- that might trigger more response than I
probably want right now...)  As a staunch defender of the Linnaean system of
nomenclature I do see some benefit in stopping the attempt to re-define the
purpose and function of Linnaean nomenclature (i.e., excessive "monophilia",
as I like to call it). And if Phylocode (or some other system of
nomenclature optimized to represent phylogenies) provides a needed sandbox
(and gets the bullies out of *my* sandbox), then the world is a better
place, in my opinion.  But this optimism is still tempered by concerns as
raised by Laurent and others (my mostly devil's-advocate ramblings above

O.K., enough for now...


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