Nomenclature codes or codes of nomenclature are the various rulebooks that govern the naming of living organisms. Standardizing the scientific names of biological organisms allows researchers to discuss findings (including the discovery of new species).
As the study of biology became increasingly specialized, specific codes were adopted for different types of organism.
To an end-user who only deals with names of species, with some awareness that species are assignable to Genus, families, and other taxa of higher ranks, it may not be noticeable that there is more than one code, but beyond this basic level these are rather different in the way they work.
Binomial Nomenclature
In taxonomy,
binomial nomenclature ("two-term naming system"), also called
binary nomenclature, is a formal system of naming
species of living things by giving each a name composed of two parts, both of which use
Latin grammar, although they can be based on words from other languages. Such a name is called a
binomial name (which may be shortened to just "binomial"), a
binomen,
name, or a
scientific name; more informally it is also historically called a
Latin name. In the ICZN, the system is also called
nomenclature,
[ ()] "binomi'N'al" with an "N" before the "al", which is a typographic error, meaning "two-name naming system".
[ ()]
The first part of the name – the generic name – identifies the genus to which the species belongs, whereas the second part – the specific name or specific epithet – distinguishes the species within the genus. For example, modern humans belong to the genus Homo and within this genus to the species Homo sapiens. Tyrannosaurus rex is likely the most widely known non-human binomial.
The formal introduction of this system of naming species is credited to Carl Linnaeus, effectively beginning with his work Species Plantarum in 1753.
Codification of Scientific Names
With all naturalists worldwide adopting binominal nomenclature, there arose several schools of thought about the details. It became ever more apparent that a detailed body of rules was necessary to govern
scientific names. From the mid-19th century onwards, there were several initiatives to arrive at worldwide-accepted sets of rules. Presently nomenclature codes govern the naming of:
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Algae, Fungus and – International Code of Nomenclature for algae, fungi, and plants ( ICN), which in July 2011 replaced the International Code of Botanical Nomenclature ( ICBN) and the earlier International Rules of Botanical Nomenclature.
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– International Code of Zoological Nomenclature ( ICZN).
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Bacterium and Archaea which are grown in cell culture – International Code of Nomenclature of Prokaryotes ( ICNP), which in 2008 replaced the International Code of Nomenclature of Bacteria ( ICNB).
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Bacterium and Archaea described from sequence data – Code of Nomenclature of Prokaryotes Described from Sequence Data ( SeqCode).
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Cultivar – International Code of Nomenclature for Cultivated Plants ( ICNCP).
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Plant associations – International Code of Phytosociological Nomenclature (ICPN).
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– The International Code of Virus Classification and Nomenclature (ICVCN); see also virus classification.
Differences between codes
Starting point
The starting point, that is the time from which these codes are in effect (usually retroactively), varies from group to group, and sometimes from rank to rank.
In
botany and
mycology, the starting point is often 1 May 1753 (
Carl Linnaeus,
Species plantarum). In
zoology, it is 1 January 1758 (Linnaeus,
Systema Naturae, 10th Edition). On the other hand,
bacteriology started anew, making a clean sweep in 1980 (Skerman et al., "Approved Lists of Bacterial Names"), although maintaining the original authors and dates of publication.
Exceptions in botany:
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Spermatophyta and Pteridophyta, suprageneric names: 4 August 1789 (Jussieu, Genera plantarum);
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Musci (except Sphagnaceae): 1 January 1801 (Johann Hedwig, Species muscorum);
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Sphagnaceae and Hepaticae (including Anthocerotae), suprageneric names: 4 August 1789 (Jussieu, Genera plantarum);
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(Fungi:) Microsporidia are governed by the ICZN (treated as animals), and see below for fossil fungi;
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(Algae:)
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Nostocaceae homocysteae: 1 January 1892 (Gomont, " Monographie des Oscillariées");
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Nostocaceae heterocysteae: 1 January 1886 (Bornet & Charles Flahault, " Révision des Nostocacées hétérocystées");
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Desmidiaceae: 1 January 1848 (John Ralfs, British Desmidieae);
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Oedogoniales: 1 January 1900 (Hirn, " Monographie und Iconographie der Oedogoniaceen");
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Fossil plant, algae ( excepted) and fungi: 31 December 1820 (Sternberg, Flora der Vorwelt).
Exceptions in zoology:[ICZN - International Commission on Zoological Nomenclature (1999). International Code of Zoological Nomenclature. Fourth Edition. The International Trust for Zoological Nomenclature, London, UK. 306 pp., [1].]
Workings
There are also differences in the way codes work. For example, the
ICN (the code for algae, fungi and plants) forbids
, while the
ICZN, (the animal code) allows them.
Terminology
These codes differ in terminology, and there is a long-term project to "harmonize" this. For instance, the
ICN uses "valid" in "valid publication of a name" (=the act of publishing a formal name), with "establishing a name" as the
ICZN equivalent. The
ICZN uses "valid" in "valid name" (="correct name"), with "correct name" as the
ICN equivalent. Harmonization is making very limited progress.
Types
There are differences in respect of what kinds of
Biological type are used. The bacteriological code prefers living type cultures, but allows other kinds. There has been ongoing debate regarding which kind of type is more useful in a case like
cyanobacteria.
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]
Other codes
BioCode
A more radical approach was made in 1997 when the IUBS/IUMS International Committee on Bionomenclature (ICB) presented the long debated
Draft BioCode, proposed to replace all existing
Codes with a harmonization of them.
The originally planned implementation date for the BioCode draft was January 1, 2000, but agreement to replace the existing
Codes was not reached.
In 2011, a revised BioCode was proposed that, instead of replacing the existing Codes, would provide a unified context for them, referring to them when necessary.[Werner Greuter (2011) BioCode 2011. Explanatory prologue. http://www.bionomenclature.net/biocode2011.html] However, participants of the last serious discussion of the draft BioCode concluded that it would probably not be implemented in their lifetimes.
PhyloCode
Many authors encountered problems in using the Linnean system in phylogenetic classification.
In fact, early proponents of rank-based nomenclature, such as Alphonse de Candolle and the authors of the 1886 version of the American Ornithologists' Union code of nomenclature already envisioned that in the future, rank-based nomenclature would have to be abandoned.
Another
Code that was developed since 1998 is the
PhyloCode, which now regulates names defined under phylogenetic nomenclature instead of the traditional Linnaean nomenclature. This new approach requires using phylogenetic definitions that refer to "specifiers", analogous to "type" under rank-based nomenclature. Such definitions delimit taxa under a given phylogeny, and this kind of nomenclature does not require use of absolute ranks. The
Code took effect in 2020, with the publication of
Phylonyms, a monograph that includes a list of the first names established under that code.
Ambiregnal protists
Some
, sometimes called
ambiregnal protists, have been considered to be both
protozoa and
algae, or
protozoa and
fungi, and names for these have been published under either or both of the
ICZN and the
ICN.
The resulting double language throughout protist classification schemes resulted in confusion.
[Adl, S. M. et al. Diversity, Nomenclature, and Taxonomy of Protists. Systematic Biology, p. 684-689, 2007, [3].][Elbrächter, M. et al. Establishing an Agenda for Calcareous Dinoflagellates Research (Thoracosphaeraceae, Dinophyceae) including a nomenclatural synopsis of generic names. Taxon 57, p. 1289–1303, 2008, [4]]
Groups claimed by both and include , , , , , many (e.g., , , , some , ), some monadoid green algae (Volvocales and ), , , and chlorarachniophytes.
, plasmodial forms and other "fungus-like" organisms claimed by both protozoologists and include , , , and labyrinthulomycetes. fungus claimed by both protozoologists and include , blastoclads, and the gut fungi.
Other problematic groups are the Cyanobacteria (ICNP/ICN), the Rozellida and Microsporidia (ICZN/ICN).
Unregulated taxa
The zoological code does not regulate names of taxa lower than subspecies or higher than superfamily. There are many attempts to introduce some order on the nomenclature of these taxa,
[Dubois, A. (2006). Proposed Rules for the incorporation of nomina of higher-ranked zoological taxa in the International Code of Zoological Nomenclature. 2. The proposed Rules and their rationale. Zoosystema, 28 (1): 165‒258, [5].][Frost, D. R. et al. (2006). The Amphibian Tree of Life. Bulletin of the American Museum of Natural History 297: 1–291, [6],] including the
PhyloCode, the Duplostensional Nomenclatural System,
and circumscriptional nomenclature.
[Klüge, N. J. (2010). Circumscriptional names of higher taxa in Hexapoda. Bionomina, 1, 15-55, [7].]
The botanical code is applied primarily to the ranks of superfamily and below. There are some rules for names above the rank of superfamily, but the principle of priority does not apply to them, and the principle of typification is optional. These names may be either automatically typified names or be descriptive names.
See also
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Binomial nomenclature
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Botanical nomenclature
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Chemical nomenclature
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Common name
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Gene nomenclature
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Glossary of scientific naming
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List of taxa named by anagrams
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Zoological nomenclature
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Tree of life (biology)
Bibliography
External links
