by Gary Rosenburg
In the June [1997] Conchatenations I discussed how to track down literature where mollusks were named. Once the publications are in hand, one must be able to determine if a name is available, that is properly published according to the rules of the International Commission on Zoological Nomenclature (ICZN), and if it is valid, the correct name for a taxon. First I'll consider availability of names.

For an ink-on-paper work to be considered published, it must be issued publicly for permanent scientific record; it must have been obtainable free of charge or for purchase at the time it was first issued; and it must have been produced in an edition of numerous, identical, simultaneously obtainable copies. Names that do not fulfill these criteria are manuscript names and are not available, for example, new species names proposed in an unpublished thesis. Also, names cannot be made available by electronic publication, such as World Wide Web pages on Internet, or CD-ROM.

The combination of a generic and a specific name is called a species name. Conus gloriamaris is a species name, Conus a generic name and gloriamaris a specific (or trivial) name. Specific and subspecific names together are called "species-group" names. For a species-group name to be available, it must be binominal and spelled in Latin letters. Binominal means having a two part name containing generic and specific names. Subgeneric names are allowed to intervene between the generic and specific names. Trinominal names are allowed in the case of subspecies. If a hyphenated or compound word is used as a species-group name, the hyphen or space is eliminated and the parts of the word fused (e.g., "gloria-maris" becomes "gloriamaris").

Names below the subspecies level (infrasubspecific names) are not available. All varietal and form names introduced after 1960 are infrasubspecific, by ICZN rule. Varietal and form names introduced before 1961 are interpreted as subspecies names unless the author's intent was clearly infrasubspecific. Sometimes intent is obvious, for example, this monster of a name: Littorina saxatilis rudis var. rudissima var. aurantia Dautzenberg & Fischer, 1912. Here "aurantia" and "rudissima" are obviously infrasubspecific. In other cases, infrasubspecific intent is inferred when an author ignores homonymy by applying the same form or varietal name to congeneric species in the same paper, e.g., Anachis costulata var. major Locard, 1897 and Anachis haliaeeti var. major Locard, 1897. A third type of infrasubspecific name is illustrated by the following pair: Voluta ancilla typica Lahille, 1895 and Voluta ancilla ponderosa Lahille, 1895. By the former name Lahille meant Voluta ancilla ancilla, but the convention of nominotypical subspecies name had not yet been established. This might also happen with names like "normalis" and "genuina." Also not available are names introduced explicitly for teratologies (monstrosities) and hybrids. If the author did not know that he was naming a teratological or hybrid specimen, then the name is available.

A name must also be accompanied by some means of identifying it, either a description or an illustration or a reference thereto for names published before 1931; or, after 1930, a description that states characters thought to differentiate the taxon, or a reference to such a statement. That is, before 1931, linkage to either a description or picture is sufficient to name a species; after 1930, a description must be present or referred to. A name that does not fulfill these criteria is a "nude name" (nomen nudum in Latin) and is not available. (Currently, the rules of zoological nomenclature recommend but do not require a picture to name a species!)

Why so much emphasis on determining whether names are available? Because names that are not available cannot be valid names and they cannot preoccupy other names. So, unless one is doing a complete nomenclatural review of a group, names that are unavailable can be disregarded as historical curiosities.

Next, from the set of available names, one must determine which names apply to which species. I will assume that one has a good grasp of the species itself, that is, one has identified the object in nature and is trying to determine its correct name. Sometimes careful study of original descriptions and illustrations is sufficient to determine what species a name refers to. In other cases one must track down type specimens in order to see what species an author meant. (Types are the original specimens on which a species or subspecies name was based.) A name that cannot be identified, usually because the type material is lost or in poor condition, is a dubious name (nomen dubium in Latin).

Once having determined which names apply to a particular species, one has identified a set of synonyms. Synonyms are names thought to apply to the same taxon. For species-group names, objective synonyms are based on the same type specimen, so the synonymy is a fact; subjective synonyms are based on different type specimens, so the synonymy is an opinion that the type specimens belong to the same species. For genus-group names, objective synonyms have the same type species, subjective synonyms have different type species.

From a set of synonyms, the correct name is usually the oldest name -- the senior synonym. This name is said to have priority. The other names are junior synonyms. Exceptions to the rule of priority are made when a junior synonym is so widely used that it would threaten the stability of nomenclature to resurrect an unused senior name, and in cases of homonymy.

Homonyms are identical names. For genus-group names to be homonyms, they must be identical, letter for letter. Species-group names that have the same derivation can have minor phonetic differences and still be homonyms, for example Helix sulfurea Hombron & Jacquinot, 1841 and Helix sulphurea C. B. Adams, 1849 are homonyms. Senior homonym refers to the name introduced first, junior homonym to the one named later; the later name is said to be preoccupied.

Primary homonyms are identical species-group names first introduced in the same genus. For example, Mitra gracilis Reeve, 1844 is a primary homonym of Mitra gracilis Lea, 1841. A junior primary homonym is permanently invalid, so Cernohorsky replaced Mitra gracilis Reeve with Cancilla gloriola Cernohorsky, 1970. Secondary homonyms were named in different genera, but later came to be classified in the same genus. If a junior secondary homonym was replaced before 1961 it is permanently invalid; if it was replaced after 1960 it is reinstated if the species are no longer considered congeneric. For example, Pustularia mariae Schilder, 1927 is usually classified as Cypraea mariae, which is a secondary homonym of Cypraea camelopardalis var. mariae Schilder, 1924. The name Cypraea mariae was replaced by Cypraea mantellum Walls & Burgess, 1980. Cypraea mantellum is the valid name for the species if it is placed in the genus Cypraea. Because the name was replaced after 1960, if it is placed elsewhere than Cypraea, however, the name reverts: thus Lorenz and Hubert (1993) correctly use the name Annepona mariae. The name Cypraea mariae must not be used.

The concepts of valid and available are often confused. A valid name is the correct name for a taxon. Many names that are available (i.e. properly published) are invalid because they are junior homonyms or junior synonyms. Usually one can decide objectively whether a name is available, but whether a name is valid is more subjective, because it can depend on the current state of knowledge, and whether one is a lumper or a splitter. Among available names, junior primary homonyms and junior objective synonyms are permanently invalid -- they will always be homonyms or synonyms. Junior secondary homonyms and junior subjective synonyms are invalid, but might become valid if ideas of classification change.

Note that the current name for a taxon is not necessarily valid. For example, Cochlespira elegans (Dall, 1881), a turrid from Florida, is a current name, but it is not a valid name. Dall named the species as Pleurotoma (Ancistrosyrinx) elegans. The name is preoccupied by Pleurotoma elegans Defrance, 1826 (and also de Blainville, 1829, Scacchi, 1835, Melleville, 1843 and Emmons, 1858). So why did I use Cochlespira elegans in my Encyclopedia of Seashells? Because no other name is available for the species, and my book wasn't the place to fix the problem.

Note that a species can have more than one valid name, because different authors can place it in different genera. Cypraea aurantium and Lyncina aurantium are both valid names for the Golden Cowrie, and Cypraea mantellum and Annepona mariae are both valid names for Marie's Cowrie. Only one name, however, can be valid for a species in a given system of classification. The rules of nomenclature allow one to determine the correct name for a particular species given the current state of knowledge and ones own beliefs about classification.

Because of the rule of priority for synonyms and homonyms, it is essential to know the correct date of publication for names. One often finds discrepancies of a year or two in the year cited for publication, particularly for names from the 19th century. Such discrepancies usually arise because the date on the title page of a journal or book is not the true date when a name was published. For example, in the 1850's the Proceedings of the Zoological Society of London ran as much as three years behind. The Proceedings for 1851 were published in three parts, one each in 1852, 1853, and 1854. In other cases, works were issued in parts, and the title page bears the date of issue of the last part. Often, external sources must be consulted to determine the true date of publication of particular pages on which species names appear. Evidence for dates of publication is most often found in the records of receipts in libraries.

Among the bibliographic sources cited in my previous column, Sherborn's Index Animalium is extremely reliable for dates of publication, as Sherborn intensively researched external sources of information and gives month of publication if known. Ruhoff's work is unreliable for dates, as she generally ignored external evidence. Goto & Poppe, being based on secondary sources, is not reliable for establishing true dates of publication. Knowing the true date of publication of a name is not merely an academic exercise: if two synonymous names were published in the same year, the one published first, even if by a single day, has priority.