[Taxacom] oldest species name priority

[Tony Rees]

Hi John,

I think you will find your question answered in the following extract from
"the Code online". Basically my understanding (hopefully correct) is that
unless the senior name qualifies as a nomen oblitum, priority is only
reversible by a ruling of the Commisison following an application setting
out sufficiently convincing grounds for doing so.... I append the relevant
wording from the Code below.

Regards - Tony
Tony Rees, New South Wales, Australia
https://about.me/TonyRees

23.9. *Reversal of precedence*

In accordance with the purpose of the Principle of Priority [Art. 23.2
<https://code.iczn.org/validity-of-names-and-nomenclatural-acts/article-23-principle-of-priority/#art-23-2>],
its application is moderated as follows:

23.9.1. prevailing usage must be maintained when the following conditions
are both met:

23.9.1.1. the senior synonym or homonym has not been used as a valid name
after 1899, and

23.9.1.2. the junior synonym or homonym has been used for a particular
taxon, as its presumed valid name, in at least 25 works, published by at
least 10 authors in the immediately preceding 50 years and encompassing a
span of not less than 10 years.

23.9.2. An author who discovers that both the conditions of 23.9.1 are met
should cite the two names together and state explicitly that the younger
name is valid, and that the action is taken in accordance with this
Article; at the same time the author must give evidence that the conditions
of Article 23.9.1.2
<https://code.iczn.org/validity-of-names-and-nomenclatural-acts/article-23-principle-of-priority/#art-23-9>
are
met, and also state that, to his or her knowledge, the condition in Article
23.9.1.1
<https://code.iczn.org/validity-of-names-and-nomenclatural-acts/article-23-principle-of-priority/#art-23-9>
applies.
>From the date of publication of that act the younger name has precedence
over the older name. When cited, the younger but valid name may be
qualified by the term *nomen protectum* and the invalid, but older, name by
the term *nomen oblitum* (see Glossary <https://code.iczn.org/glossary/>).
In the case of subjective synonymy, whenever the names are not regarded as
synonyms the older name may be used as valid.

*Example.* The valid name of a species formed by including the nominal
taxa *Aus
xus* Schmidt, 1940 and *Aus wus* Jones, 1800 in a single taxonomic species
is *Aus wus* Jones, 1800. But if the conditions in
Article 23.9.1.1 and 23.9.1.2 are met, then *Aus xus* Schmidt, 1940 becomes
(unless the Commission rules otherwise) the valid name of that species.
However, if the nominal taxa do refer to separate taxonomic species the
names of these are *Aus xus* Schmidt, 1940 and *Aus wus *Jones, 1800. If,
on the other hand, the two taxa are treated as subspecies of a single
species then the names of these are *Aus xus xus* Schmidt, 1940 and *Aus
xus wus* Jones, 1800 - not *Aus wus xus* Schmidt, 1940 and *Aus wus wus* Jones,
1800.

*Recommendation 23A.* *If suppression desired. *If in the opinion of an
author suppression of the older name, rather than a change in the relative
precedence of the two names involved, is desirable, in addition to taking
action under Article 23.9.2
<https://code.iczn.org/validity-of-names-and-nomenclatural-acts/article-23-principle-of-priority/#art-23-9>to
maintain prevailing usage, the author should refer the case to the
Commission with an appropriate recommendation for a ruling.

23.9.3. If the conditions of 23.9.1 are not met but nevertheless an author
considers that the use of the older synonym or homonym would threaten
stability or universality or cause confusion, and so wishes to maintain use
of the younger synonym or homonym, he or she must refer the matter to the
Commission for a ruling under the plenary power [Art. 81
<https://code.iczn.org/the-international-commission-on-zoological-nomenclature/article-81-use-of-the-plenary-power/>].
While the case is under consideration use of the junior name is to be
maintained [Art. 82
<https://code.iczn.org/the-international-commission-on-zoological-nomenclature/article-82-status-of-case-under-consideration/>
].


On Fri, 24 Apr 2020 at 05:15, John Grehan via Taxacom <
taxacom at mailman.nhm.ku.edu> wrote:

> Dear colleagues,
>
> I would be grateful for comment regarding use of names where normally the
> oldest validly published name takes priority. But do the rules of
> nomenclature allow for acceptance of a later name where it has been widely
> used over a long period of time if an application is made to that effect? I
> recall that this can be done, but would be grateful for clarification.
>
> john Grehan
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