Note 9 - Validity and availability of Maylandia - The technical details Validity and availability of Maylandia — The technical details
This note provides further information supporting my discussion of the reasons why the genus Metriaclima, proposed by Stauffer et al. (1997), is a junior synonym of the earlier Pseudotropheus subgenus Maylandia of Meyer & Foerster (1984). (Maylandia was proposed for a subgenus of the genus Pseudotropheus, and therefore is also usable as a genus apart from Pseudotropheus for P. zebra, P. greshakei, and their presumed relatives.) Although Condé & Géry (1999) also conclude that Maylandia is an available name and Metriaclima therefore its junior synonym, the following reasoning is entirely my own.

The International Code of Zoological Nomenclature (ICZN or Code) spells out the requirements for a new scientific species-, genus-, or family-group name of an animal to be considered published for the purposes of zoological nomenclature, and available in a manner that allows it to "compete" with any other names that are also published and available for the same animal. The Code also specifies how to determine, in most situations, which one of multiple available names is the one valid name.

That Maylandia was properly published in the meaning of the ICZN has not, to my knowledge, ever been disputed. This name was clearly published in a manner that fulfills the criteria of the Code. These requirements include being issued for the purpose of permanent, public, scientific record; being obtainable either by purchase or free of charge when first issued; and being produced in an edition of numerous identical, durable copies that are simultaneously available (Article 8.1). Because Meyer & Foerster's paper was published before 1986, it is subject to an additional requirement that it must have been produced on paper, either by a printing method that was conventional at the time, such as letterpress or offset printing, or else by hectographing or mimeographing (Article 8.4). The publication fulfilled this criterion. Further, even having passed all the hurdles in Article 8, a work also must not fall into any of nine categories specifically excluded from constituting publication (Article 9), such as microfilms, specimen labels, and sound recordings. Again, Meyer & Foerster's article passes all tests.

What has been controversial, rather, is whether Maylandia fulfills the Code's criteria of availability.

Availability has numerous preconditions and requirements. Article 10 sets out general conditions and possible special situations; Maylandia encounters no problems in this section. Article 11 contains the basic requirements for availability. Once more, there are general provisions which Maylandia satisfies, such as publication (again), required use of the Latin alphabet, and permissible derivation. Article 12 applies only to names published before 1931.

Article 13 of the Code is where those who would deny the availability of Maylandia hope to get their ammunition. Stauffer and colleagues (1997), as I already noted in the main discussion, asserted that "...although Maylandia was proposed as a subgenus no description or diagnosis accompanied this suggestion. Therefore, Maylandia, in effect, is a nomen nudum and thus an invalid name." If it is true that Meyer & Foerster's description contains no description or diagnosis of their subgenus Maylandia, then Stauffer et al. would be correct, the name is not available, and Metriaclima would carry the day. What, exactly, are a description and a diagnosis, in the meaning of the ICZN?

The Code's glossary defines "description" as "A statement in words of taxonomic characters of a specimen or a taxon." [A "taxon" (plural "taxa") is "A taxonomic unit, whether named or not: i.e. a population or group of populations of organisms which are usually inferred to be phylogenetically related and which have characters in common which differentiate... the unit (e.g. a geographic population, a genus, a family, an order) from other such units...."] A "diagnosis" is defined as "A statement in words that purports to give those characters which differentiate the taxon from other taxa with which it is likely to be confused." (Notice that key word "purports"; the characters need not actually permit recognition of the creature — it need only be asserted that they do so.)

Returning to Article 13, we find a definite "Requirement" for a description; all new names published after 1930 have to " accompanied by a description or definition that states in words characters that are purported to differentiate the taxon..." (once again, notice that word "purported").

Article 13 also addresses the diagnosis: "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." But, this diagnosis is not a requirement; the language just quoted is from Recommendation 13A. (The Code's glossary explains that a Recommendation is an "...advisory statement in an Article of the Code," and specifically states that Recommendations "...are not mandatory....") A diagnosis is a good idea, but it is not the law.

NOTE: SVEN KULLANDER ADDRESSED THE SAME MATTER AND SHOULD BE CITED, IN HIS cichlid-l POST: The entire subject was brought to a definite conclusion in the Feb 1999 archive (threads variously titled "," "Maylandia," and "Maylandia and Metricalima." Nails in the coffin: here
The latter post also cites other publications by ichthyologists concluding Maylandia it is.


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