[Taxacom] Use of geographic range data as diagnostic characters
stephen_thorpe at yahoo.co.nz
Sun Feb 17 19:58:23 CST 2013
Clearly, an original description or diagnosis based SOLELY on geographic location would not be allowed by the Code, and would not be a good idea anyway! But I'm not sure that the original question of this thread was meaning anything so extreme as that?
From: Doug Yanega <dyanega at ucr.edu>
To: TAXACOM at MAILMAN.NHM.KU.EDU
Sent: Monday, 18 February 2013 2:39 PM
Subject: Re: [Taxacom] Use of geographic range data as diagnostic characters
>It seems the code has some constraints on what constitutes a valid
>character, but is not exhaustive and I remain unconvinced that it
>explicitly forbids reliance on locality as a diagnostic trait to establish
>a new taxon. I do hope to be proven wrong on this point!
and Francisco responded:
>This discussion suggests that it would be useful to include a note in the
>Glossary's definition for "character" to exclude a locality to be
>interpreted as a character. Maybe also in Art. 13.1.1 an additional note
>in this sense could be helpful to have a clear guideline.
>There is a general rule in the Code that the younger the date, the
>stricter the rules. So from this point it is logical that if a locality is
>not allowed to be interpreted as a description for names before 1931, much
>less will it be for names after 1930.
In a way this is second-guessing what was already a correct response
(from my perspective). Specifically, the terminology used in Arts.
12.3 and 13.1.1 are *intended* to be taken together, and I believe
12.3 does constitute an explicit prohibition of locality data.
Since it was cited ealier in the thread, I'll re-cite it:
> >> Art. 13 talks about names established later and is even more explicit in
>>> its Art. 13.1.1 where is said "a description or definition that states
>>> words characters that are purported to differentiate the taxon".
>>> > ICZN:
>>> > 12.3. Exclusions. The mention of any of the following does not in
> >> > constitute a description, definition, or indication: a vernacular
> >> > locality, geological horizon, host, label, or specimen.
It is not as important to focus on what the Code means by
"characters" as it is to focus on what it means by "description or
definition". In other words, the key clause in 13.1.1 is that there
must be a "description or definition" and 12.3 gives a list of things
which are explicitly NOT, in and of themselves, to be interpreted as
"a description, definition, or indication". None of the items listed
in 12.3 can be used to satisfy 13.1.1 (and, giving the same exact
list under Article 13 would be entirely redundant). Accordingly, my
interpretation is that even though some of the items in 12.3 could be
used as diagnostic aids (namely locality, host, and geological
horizon), they cannot satisfy 13.1.1, because something *else* must
be used to create a "description".
For those who insist on rewording the glossary for clarification (and
if this is being forwarded to Gary for the wiki), I would offer the
following as an appropriate and objective definition of "character":
"Any property of a taxon that can be objectively derived and
evaluated via direct examination of individual specimens belonging to
that taxon; i.e., without recourse to external sources of
information, such as labels, photos or illustrations, maps or field
notes, isotope dating, statistical analyses, or phylogenetic trees."
Note that this definition would also exclude all of the items
excluded under 12.3, while including gene sequences. Perhaps the one
contentious item - and I would strongly defend it - is the exclusion
of anything that is statistical in nature. Lest this be
misinterpreted, something like (e.g.) "wing length 12.2-15.7 mm"
would be a character, because it is descriptive, and an individual
specimen could (during a diagnostic process) be evaluated as to
whether it does or does not comply with the specifications for that
feature. However, something like "mean wing length 13.6 mm" would NOT
be a character, because it is not a property that can be evaluated
for an individual specimen, but only for a *group* of specimens.
Doug Yanega Dept. of Entomology Entomology Research Museum
Univ. of California, Riverside, CA 92521-0314 skype: dyanega
phone: (951) 827-4315 (standard disclaimer: opinions are mine, not UCR's)
"There are some enterprises in which a careful disorderliness
is the true method" - Herman Melville, Moby Dick, Chap. 82
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