Source: http://iczn.ansp.org/wiki/Article13
Timestamp: 2019-04-20 02:11:25+00:00

Document:
Article 13. Names published after 1930.
13.1.3. be proposed expressly as a new replacement name (nomen novum) for an available name, whether required by any provision of the Code or not.
Recommendation 13A. Intent to differentiate. When describing a new nominal taxon, an author should make clear his or her purpose to differentiate the taxon by including with it a diagnosis, that is to say, a summary of the characters that differentiate the new nominal taxon from related or similar taxa.
Recommendation 13B. Language. Authors should publish diagnoses of new taxa in languages widely used internationally in zoology. The diagnoses should also be given in languages used in the regions relevant to the taxa diagnosed.
13.2. Family-group names. To be available, every new family-group name published after 1930 must satisfy the provisions of Article 13.1 and must be formed from an available genus-group name then used as valid by the author in the family-group taxon [Arts. 11.7.1.1, 29].
13.2.1. A family-group name first published after 1930 and before 1961 which does not satisfy the provisions of Article 13.1 is available from its original publication only if it was used as valid before 2000, and also was not rejected by an author who, after 1960 and before 2000, expressly applied Article 13 of the then current editions of the Code.
13.3. Genus-group names. To be available, every new genus-group name published after 1930 (except those proposed for collective groups or ichnotaxa) must, in addition to satisfying the provisions of Article 13.1, be accompanied by the fixation of a type species in the original publication [Art. 68] or be expressly proposed as a new replacement name (nomen novum) [Art. 67.8].
13.3.1. If the name of a genus-group taxon established before 1931 is replaced by a new replacement name (nomen novum) after 1930, the type species of the nominal taxon must then be designated, if one has not already been fixed.
13.3.2. A name published at any time for a collective group [Art. 66] need not be accompanied by a type species fixation, since collective groups have no type species [Art. 42.3.1].
13.3.3. A name published for an ichnotaxon at the genus-group level before 2000 need not be accompanied by a type species fixation; but if such a name is replaced after 1999 by a new replacement name (nomen novum) a type species must then be designated, if one has not already been fixed [Art. 66.1].
13.4. Combined description of new genus-group taxon and new species. The combined description or definition of a new nominal genus or subgenus and a single included new nominal species, if marked by "gen. nov., sp. nov." or an equivalent expression, is deemed to confer availability on each name under Article 13.1.1 (a species-group taxon so described after 1999 must also satisfy the conditions of Article 16.4).
13.5. Combined description of new family-group taxon and new genus. The combined description or definition of a new nominal family-group taxon and a single new nominal genus of which the name provides the basis for the new family-group name [Art. 11.5] is deemed to confer availability on each name under Article 13.1.1, but for such names published after 1930 availability is not conferred on either name unless a type species is fixed for the new nominal genus [Arts. 13.2 and 13.3].
Recommendation 13C. Individual descriptions and definitions. Authors are urged to avoid publishing combined descriptions and definitions. Each new nominal taxon should be differentiated from other taxa at the same rank.
13.6.1. A name proposed after 1930 cannot be made available by the methods of "indication" listed in Article 12.2.2, 12.2.4 (but see Article 13.2.1), 12.2.5 and 12.2.7.
13.6.2. A name proposed after 1930 which is based on the work of an extant animal is excluded from zoological nomenclature [Art. 1.3.6].
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"Vernacular names, localities, geological horizons or hosts are not characters in the sense of this definition."
This sentence could also be added here.
It has repeatedly been argued in discussions that a locality could represent a valid description (example: [Taxacom] listserver, Feb 2013). To avoid confusion it would be useful to clarify this point directly in the legal text of the Code, so that unexperienced users of the Code will find more quickly the answer to this frequent question.
For the experienced user it is logical that if localities are not allowed to count as descriptions before 1931, much less will the Code allow this for names established after 1930.
I saw also genera established without explicit description but with one (previously established) nominal species included for which a description was given (an example is Pseudogracilinenia Loosjes & Loosjes-van Bemmel, 1984, Zoologische Verhandelingen, 212: 10). It seems to be generally accepted that such a description covers also the requirement of Art. 13.1.1. But to avoid disputes and divergent Code interpretations it is desirable to have this expressed explicitly in the Article.
We'd need an exception or specification of the rule for simultaneously established species and genera. If a new monotypic genus was established and a description was given for the species, it is not necessary to give a description for the genus. Literally ("every new name") the missing description for the genus could render it unavailable.
Examples: gastropod names Portugala Gittenberger, 1980 and Gasulliella Gittenberger, 1980, both established as monotypic genera without description for the genus as such.
I am asking myself what is the difference between description and diagnosis. If there is none (a diagnosis is a description), then delete diagnosis. It only leads to confusion.
This article is a crucial point in the Code (for many zoologists this might be the only article of the Code they'd ever consult), and its interpretation should not remain too arbitrary. Especially for unexperienced readers some specifications could help to rule out some interpretations.
I currently do not see why we have such a help in Art. 12.3 where the term "description" is specified for names established before 1930, but not an equivalent article in Art. 13 for names established after 1930.
Art. 13.6.3. The mention of any of the following does not in itself constitute a description: a vernacular name, locality, geological horizon, host, label, GenBank accession number, or specimen. For the purpose to differentiate the taxon the following statements are not sufficient: "can be seen in autumn; beautiful; resembles very much species B and C; size like in species B of the same genus; can be distinguished very easily from species B by its very well recognisable morphological characters; colour differs from species B; DNA differs from species B; molecular distance so large from taxon B that it must be considered a different taxon".
There has been another case in one of the mailing lists in 2009, where "size ranges at the lower margin of species B" was addressed as problematic. It might be good to add that statement also to the above list.
Regarding Sven's proposal to allow localities: this is excluded for names established before 1930 in Art. 12.3. I would not change this.
A new Article would be helpful.
"13.3.4. If a genus-group name was expressly established as a new replacement name and a type species was originally designated at this occasion, and the replaced genus-group name already had another type species fixed, then the name is to be regarded as a simple new name with its type species fixed at this occasion."
This is necessary to rule out the conflict between two ways to interprete such a situation (new name with new type species, or new replacement name with old type species against the intention of the author?).
GaryRosenberg Regarding the comment that subspecies are distinguished only by geography: that is one particular definition of subspecies, so it is in the realm of taxonomy. The Code must support other uses of subspecies as well.
SvenKullander I do not think it is necessary to distinguish between purported and definite differences. We just have to assume that "purported" means "as good as can possibly be". But I agree, this again is an English word that falls outside of the realm of precise terminology.
"accompanied" also is a very obscure expression. "Description" and "definition" are possibly in the Glossary, I did not check. They are abstractions, that do not serve a purpose of precision.
Recommendation 13A does not look like it has much other function than redundancy. It should be deleted.
FranciscoWelterSchultes I propose to add also a cross-reference to Art. 12.3.
This should exclude a possible interpretation in that a locality or host could represent a character. Alternatively, a reference could also be given to the Glossary, where the contents of Art. 12.3 should be repeated (see my comment under Glossary).
Just stating the characters doesn't help. 'It can be differentiated by DNA, distribution and size' states in words the characters, but doesn't give the differentiation. We need the species diagnostic sequences, measurements and the range, e.g.
It doesn't matter whether the character states pretend or really are differentiating a new taxon from another, because this is a question of science and ever changing scientific knowledge, but it should not only be stated what is different but how it is different.
Wulf Schleip >I believe that "that differentiate" cannot be used in such a sense because science is not definite, nobody can be required to know the eternal truth, we can only say "that are believed to differentiate", "thought to differentiate", assumed, meant, intended, or use likewise expressions.
Francisco, well science may not be definite in the long-run (we don't know the future), but as a snapshot (our current knowledge and understanding) it should be definite; means that science does not only rely on speculation or gut feelings, rather than on evidence (e.g., presented data) provided. The acceptance of hypotheses by the scientific community depends very much on how convincing the presented evidence is. So why do taxonomists of all disciplines accept almost every validly (in accordance with the most basic rules of the code) published gut feeling then without evidence? Science must not be definite, but characters used to differentiate taxa should, they should be real (One could simply describe/diagnose a new species by stating that the population left of the bridge is darker in color than the one on the right side. This must not even be true, and one has created a senior synonym.
At the end of the day, we are not talking about science or taxonomy, we are talking about formalism in nomenclature, that's not science, it's a tool for naming something. Even the basic rules of the code are subject to interpretation, with contrary opinions even within professionals.
FranciscoWelterSchultes 13.1.3 needs some examples and cross-references to 67.8 and 72.2.
It seems to be necessary to explain more explicitely (1) that an expressly established replacement name for an unavailable name is not to be regarded as a replacement name, (2) that such a name might then be a normally established new name if the other conditions are met (and a nomen nudum if not), and (3) that "sensu" names are no available names in the sense of this article.
The cross references would be helpful because there is no chapter on replacement names in the Code and looking for rules concerning replacement names in the Code is a hard job.
1. Hartmann 1841 used the name Sphyradium Charpentier, 1837 for a species Charpentier did not know. Westerlund 1887 established Coryna for 7 species and mentioned that Hartmann 1841 had used the name Sphyradium for the same group, not in the sense of Charpentier 1837 (Sphyradium Charpentier, 1837 contained other species in 1887). Coryna was not established as a new replacement name (1) because it did not contain an expressed statement, (2) because Hartmann 1841 had used Charpentier's name and had not established an available name. Coryna is available as a regular new name from Westerlund 1887, its type is to be selected among Westerlund's 7 species.
2. Helix bielzi "Schmidt" was mentioned by Bielz 1859 without description and with a statement that a local species previously called Helix leucozona Pfeiffer, 1828 differed from Pfeiffer's taxon and should carry the name Helix bielzi "Schmidt". Helix bielzi was not established as a new replacement name for Helix leucozona sensu Bielz 1853 non Pfeiffer, 1828 here, because there was no available name to be replaced, since Helix leucozona had previously been used in Pfeiffer's sense, and Bielz did not intend to replace Pfeiffer's original name. Bielz 1859 did not give a bibliographical reference to Bielz 1853 (where the local species was described), so Helix bielzi Bielz, 1859 is a nomen nudum. Bielz 1860 mentioned Helix bielzi "Schmidt" again, with a short diagnosis given by Bielz. This made the name Helix bielzi Bielz, 1860 available.
I believe that "that differentiate" cannot be used in such a sense because science is not definite, nobody can be required to know the eternal truth, we can only say "that are believed to differentiate", "thought to differentiate", assumed, meant, intended, or use likewise expressions.
13.1.1 should be more precise and explicit in that it requires characters that not only pretend (purport) to differentiate the taxon, but really do (in the light of the evidence provided by the author).
FranciscoWelterSchultes 13.3 should be more explicite and less confusing.
"To be available, every new genus-group name published after 1930 (...) must, in addition to satisfying the provisions of Article 13.1, be accompanied by the fixation of a type species in the original publication [Art. 68.1-4 - by original designation, monotypy or absolute tautonymy] or be expressly proposed as a new replacement name (nomen novum) [Art. 67.8]."
This is necessary because many believe that after 1930 the type must be originally designated, and that monotypy would not be allowed. Only very skilled specialists know the difference between the terms fixation and designation.

References: Art. 13
 Art. 12
 Art. 13

Art. 13
 Art. 12
 Art. 12
 Art. 12