Synonym (taxonomy)

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In scientific nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name, [1] although the term is used somewhat differently in the zoological code of nomenclature. [2] For example, Linnaeus was the first to give a scientific name (under the currently used system of scientific nomenclature) to the Norway spruce, which he called Pinus abies. This name is no longer in use: it is now a synonym of the current scientific name, Picea abies .

Nomenclature (ˈnəʊmənˌkleɪtʃə/) is a system of names or terms, or the rules for forming these terms in a particular field of arts or sciences. .The principal of naming vary from the relatively informal conventions of everyday speech to the internationally agreed principles, rules and recommendations that govern the formation and use of the specialist terms used in scientific and any other disciplines.

Binomial nomenclature, also called binominal nomenclature or 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 grammatical forms, although they can be based on words from other languages. Such a name is called a binomial name, a binomen, binominal name or a scientific name; more informally it is also called a Latin name. The first part of the name – the generic name – identifies the genus to which the species belongs, while the second part – the specific name or specific epithet – identifies the species within the genus. For example, humans belong to the genus Homo and within this genus to the species Homo sapiens. Tyrannosaurus rex is probably the most widely known binomial. The formal introduction of this system of naming species is credited to Carl Linnaeus, effectively beginning with his work Species Plantarum in 1753. But Gaspard Bauhin, in as early as 1623, had introduced in his book Pinax theatri botanici many names of genera that were later adopted by Linnaeus.

Taxon Group of one or more populations of an organism or organisms which have distinguishing charachterisics in common

In biology, a taxon is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is not uncommon, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping.


Unlike synonyms in other contexts, in taxonomy a synonym is not interchangeable with the name of which it is a synonym. In taxonomy, synonyms are not equals, but have a different status. For any taxon with a particular circumscription, position, and rank, only one scientific name is considered to be the correct one at any given time (this correct name is to be determined by applying the relevant code of nomenclature). A synonym cannot exist in isolation: it is always an alternative to a different scientific name. Given that the correct name of a taxon depends on the taxonomic viewpoint used (resulting in a particular circumscription, position and rank) a name that is one taxonomist's synonym may be another taxonomist's correct name (and vice versa).

Synonym Words or phrases having the same meaning

A synonym is a word or phrase that means exactly or nearly the same as another lexeme in the same language. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. For example, the words begin, start, commence, and initiate are all synonyms of one another. Words are typically synonymous in one particular sense: for example, long and extended in the context long time or extended time are synonymous, but long cannot be used in the phrase extended family. Synonyms with the exact same meaning share a seme or denotational sememe, whereas those with inexactly similar meanings share a broader denotational or connotational sememe and thus overlap within a semantic field. The former are sometimes called cognitive synonyms and the latter, near-synonyms, plesionyms or poecilonyms.

In biological taxonomy, circumscription is the definition of a taxon, that is, a group of organisms.

Nomenclature codes or codes of nomenclature are the various rulebooks that govern biological taxonomic nomenclature, each in their own broad field of organisms. To an end-user who only deals with names of species, with some awareness that species are assignable to families, 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.

Synonyms may arise whenever the same taxon is described and named more than once, independently. They may also arise when existing taxa are changed, as when two taxa are joined to become one, a species is moved to a different genus, a variety is moved to a different species, etc. Synonyms also come about when the codes of nomenclature change, so that older names are no longer acceptable; for example, Erica herbacea L. has been rejected in favour of Erica carnea L. and is thus its synonym. [3]

Carl Linnaeus Swedish botanist, physician, and zoologist

Carl Linnaeus, also known after his ennoblement as Carl von Linné, was a Swedish botanist, physician, and zoologist who formalised binomial nomenclature, the modern system of naming organisms. He is known as the "father of modern taxonomy". Many of his writings were in Latin, and his name is rendered in Latin as Carolus Linnæus.

A conserved name or nomen conservandum is a scientific name that has specific nomenclatural protection. Nomen conservandum is a Latin term, meaning "a name to be conserved". The terms are often used interchangeably, such as by the International Code of Nomenclature for Algae, Fungi, and Plants (ICN), while the International Code of Zoological Nomenclature favours the term "conserved name".

<i>Erica carnea</i> species of plant

Erica carnea is a species of flowering plant in the family Ericaceae native to mountainous areas of central and southern Europe, where it grows in coniferous woodlands or stony slopes.

General usage

To the general user of scientific names, in fields such as agriculture, horticulture, ecology, general science, etc., a synonym is a name that was previously used as the correct scientific name (in handbooks and similar sources) but which has been displaced by another scientific name, which is now regarded as correct. Thus Oxford Dictionaries Online defines the term as "a taxonomic name which has the same application as another, especially one which has been superseded and is no longer valid." [4] In handbooks and general texts, it is useful to have synonyms mentioned as such after the current scientific name, so as to avoid confusion. For example, if the much advertised name change should go through and the scientific name of the fruit fly were changed to Sophophora melanogaster, it would be very helpful if any mention of this name was accompanied by "(syn. Drosophila melanogaster)". Synonyms used in this way may not always meet the strict definitions of the term "synonym" in the formal rules of nomenclature which govern scientific names (see below).

<i>Drosophila melanogaster</i> Species of fruit fly

Drosophila melanogaster is a species of fly in the family Drosophilidae. The species is known generally as the common fruit fly or vinegar fly. Starting with Charles W. Woodworth's proposal of the use of this species as a model organism, D. melanogaster continues to be widely used for biological research in genetics, physiology, microbial pathogenesis, and life history evolution. As of 2017, eight Nobel prizes had been awarded for research using Drosophila.

Changes of scientific name have two causes: they may be taxonomic or nomenclatural. A name change may be caused by changes in the circumscription, position or rank of a taxon, representing a change in taxonomic, scientific insight (as would be the case for the fruit fly, mentioned above). A name change may be due to purely nomenclatural reasons, that is, based on the rules of nomenclature;[ citation needed ] as for example when an older name is (re)discovered which has priority over the current name. Speaking in general, name changes for nomenclatural reasons have become less frequent over time as the rules of nomenclature allow for names to be conserved, so as to promote stability of scientific names.


The Latin Caudata and Greek Urodela both mean "tailed" and have been used as a scientific name at the taxonomic rank of order for the salamanders (as opposed to the tail-less frogs). Thus they are synonyms. Triturus boscai.001.JPG
The Latin Caudata and Greek Urodela both mean "tailed" and have been used as a scientific name at the taxonomic rank of order for the salamanders (as opposed to the tail-less frogs). Thus they are synonyms.

In zoological nomenclature, codified in the International Code of Zoological Nomenclature , synonyms are different scientific names of the same taxonomic rank that pertain to that same taxon. For example, a particular species could, over time, have had two or more species-rank names published for it, while the same is applicable at higher ranks such as genera, families, orders, etc. In each case, the earliest published name is called the senior synonym, while the later name is the junior synonym. In the case where two names for the same taxon have been published simultaneously, the valid name is selected accorded to the principle of the first reviser such that, for example, of the names Strix scandiaca and Strix noctua (Aves), both published by Linnaeus in the same work at the same date for the taxon now determined to be the snowy owl, the epithet scandiaca has been selected as the valid name, with noctua becoming the junior synonym (this species is currently classified in the genus Bubo , as Bubo scandiacus [5] ).

The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the International Commission on Zoological Nomenclature. The rules principally regulate:

Taxonomic rank Level in a taxonomic hierarchy

In biological classification, taxonomic rank is the relative level of a group of organisms in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, order, class, phylum, kingdom, domain, etc.

Snowy owl species of owl, bird

The snowy owl is a large, white owl of the typical owl family. Snowy owls are native to Arctic regions in North America and Eurasia. Males are almost all white, while females have more flecks of black plumage. Juvenile snowy owls have black feathers until they turn white. The snowy owl is a ground nester that primarily hunts rodents and waterfowl, and opportunistically eats carrion. Most owls sleep during the day and hunt at night, but the snowy owl is active during the day, especially in the summertime.

One basic principle of zoological nomenclature is that the earliest correctly published (and thus available) name, the senior synonym, by default takes precedence in naming rights and therefore, unless other restrictions interfere, must be used for the taxon. However, junior synonyms are still important to document, because if the earliest name cannot be used (for example, because the same spelling had previously been used for a name established for another taxon), then the next available junior synonym must be used for the taxon. For other purposes, if a researcher is interested in consulting or compiling all currently known information regarding a taxon, some of this (including species descriptions, distribution, ecology and more) may well have been published under names now regarded as outdated (i.e., synonyms) and so it is again useful to know a list of historic synonyms which may have been used for a given current (valid) taxon name.

Objective synonyms refer to taxa with the same type and same rank (more or less the same taxon, although circumscription may vary, even widely). This may be species-group taxa of the same rank with the same type specimen, genus-group taxa of the same rank with the same type species or if their type species are themselves objective synonyms, of family-group taxa with the same type genus, etc. [6]

In the case of subjective synonyms, there is no such shared type, so the synonymy is open to taxonomic judgement, [7] meaning that there is room for debate: one researcher might consider the two (or more) types to refer to one and the same taxon, another might consider them to belong to different taxa. For example, John Edward Gray published the name Antilocapra anteflexa in 1855 for a species of pronghorn, based on a pair of horns. However, it is now commonly accepted that his specimen was an unusual individual of the species Antilocapra americana published by George Ord in 1815. Ord's name thus takes precedence, with Antilocapra anteflexa being a junior subjective synonym.

Objective synonyms are common at the rank of genera, because for various reasons two genera may contain the same type species; these are objective synonyms. [8] In many cases researchers established new generic names because they thought this was necessary or did not know that others had previously established another genus for the same group of species. An example is the genus Pomatia Beck, 1837, [9] which was established for a group of terrestrial snails containing as its type species the Burgundy or Roman snail Helix pomatia —since Helix pomatia was already the type species for the genus Helix Linnaeus, 1758, the genus Pomatia was an objective synonym (and useless). At the same occasion Helix is also a synonym of Pomatia, but it is older and so it has precedence.

At the species level, subjective synonyms are common because of an unexpectedly large range of variation in a species, or simple ignorance about an earlier description, may lead a biologist to describe a newly discovered specimen as a new species. A common reason for objective synonyms at this level is the creation of a replacement name.

It is possible for a junior synonym to be given precedence over a senior synonym, [10] primarily when the senior name has not been used since 1899, and the junior name is in common use. The older name may be declared to be a nomen oblitum , and the junior name declared a nomen protectum . This rule exists primarily to prevent the confusion that would result if a well-known name, with a large accompanying body of literature, were to be replaced by a completely unfamiliar name. An example is the European land snail Petasina edentula (Draparnaud, 1805). In 2002, researchers found that an older name Helix depilata Draparnaud, 1801 referred to the same species, but this name had never been used after 1899 and was fixed as a nomen oblitum under this rule by Falkner et al. 2002. [11]

Such a reversal of precedence is also possible if the senior synonym was established after 1900, but only if the International Commission on Zoological Nomenclature (ICZN) approves an application. (Note that here the C in ICZN stands for Commission, not Code as it does at the beginning of § Zoology. The two are related, with only one word difference between their names.) For example, the scientific name of the red imported fire ant, Solenopsis invicta was published by Buren in 1972, who did not know that this species was first named Solenopsis saevissima wagneri by Santschi in 1916; as there were thousands of publications using the name invicta before anyone discovered the synonymy, the ICZN, in 2001, ruled that invicta would be given precedence over wagneri.

To qualify as a synonym in zoology, a name must be properly published in accordance with the rules. Manuscript names and names that were mentioned without any description ( nomina nuda ) are not considered as synonyms in zoological nomenclature.


In botanical nomenclature, a synonym is a name that is not correct for the circumscription, position, and rank of the taxon as considered in the particular botanical publication. It is always "a synonym of the correct scientific name", but which name is correct depends on the taxonomic opinion of the author. In botany the various kinds of synonyms are:

In botany, although a synonym must be a formally accepted scientific name (a validly published name): a listing of "synonyms", a "synonymy", often contains designations that for some reason did not make it as a formal name, such as manuscript names, or even misidentifications (although it is now the usual practice to list misidentifications separately [12] ).

Comparison between zoology and botany

Although the basic principles are fairly similar, the treatment of synonyms in botanical nomenclature differs in detail and terminology from zoological nomenclature, where the correct name is included among synonyms, although as first among equals it is the "senior synonym":

Synonym lists

Scientific papers may include lists of taxa, synonymizing existing taxa and (in some cases) listing references to them.

The status of a synonym may be indicated by symbols, as for instance in a system proposed for use in paleontology by Rudolf Richter. In that system a v before the year would indicate that the authors have inspected the original material; a . that they take on the responsibility for the act of synonymizing the taxa. [13]

Other usage

The traditional concept of synonymy is often expanded in taxonomic literature to include pro parte (or "for part") synonyms. These are caused by splits and circumscriptional changes. They are usually indicated by the abbreviation "p.p." [14] For example:

See also

Related Research Articles

A genus is a taxonomic rank used in the biological classification of living and fossil organisms, as well as viruses, in biology. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus.

Subspecies taxonomic rank subordinate to species

In biological classification, the term subspecies refers to a unity of populations of a species living in a subdivision of the species' global range and varies from other populations of the same species by morphological characteristics. A subspecies cannot be recognized independently. A species is either recognized as having no subspecies at all or at least two, including any that are extinct. The term is abbreviated subsp. in botany and bacteriology, or ssp. in zoology. The plural is the same as the singular: subspecies.

Type species term used in zoological nomenclature (also non-officially in botanical nomenclature)

In zoological nomenclature, a type species is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen(s). A similar concept is used for suprageneric groups called a type genus.

Type (biology) Specimen(s) to which a scientific name is formally attached

In biology, a type is a particular specimen of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralize the defining features of that particular taxon. In older usage, a type was a taxon rather than a specimen.

In the scientific name of organisms, basionym or basyonym means the original name on which a new name is based; the author citation of the new name should include the authors of the basionym in parentheses. The term original combination or protonym is used in the same way in zoology. Bacteriology uses a similar term, basonym, spelled without an i.

Botanical name scientific name for a plant (or alga or fungus) (ICNafp)

A botanical name is a formal scientific name conforming to the International Code of Nomenclature for algae, fungi, and plants (ICN) and, if it concerns a plant cultigen, the additional cultivar or Group epithets must conform to the International Code of Nomenclature for Cultivated Plants (ICNCP). The code of nomenclature covers "all organisms traditionally treated as algae, fungi, or plants, whether fossil or non-fossil, including blue-green algae (Cyanobacteria), chytrids, oomycetes, slime moulds and photosynthetic protists with their taxonomically related non-photosynthetic groups ."

A tautonym is a scientific name of a species in which both parts of the name have the same spelling, for example Rattus rattus. The first part of the name is the name of the genus and the second part is referred to as the specific epithet in the International Code of Nomenclature for algae, fungi, and plants and the specific name in the International Code of Zoological Nomenclature.

Botanical nomenclature is the formal, scientific naming of plants. It is related to, but distinct from taxonomy. Plant taxonomy is concerned with grouping and classifying plants; botanical nomenclature then provides names for the results of this process. The starting point for modern botanical nomenclature is Linnaeus' Species Plantarum of 1753. Botanical nomenclature is governed by the International Code of Nomenclature for algae, fungi, and plants (ICN), which replaces the International Code of Botanical Nomenclature (ICBN). Fossil plants are also covered by the code of nomenclature.

In botany, the correct name according to the International Code of Nomenclature for algae, fungi, and plants (ICN) is the one and only botanical name that is to be used for a particular taxon, when that taxon has a particular circumscription, position and rank. Determining whether a name is correct is a complex procedure. The name must be validly published, a process which is defined in no less than 16 Articles of the ICN. It must also be "legitimate", which imposes some further requirements. If there are two or more legitimate names for the same taxon, then the correct name is the one which has priority, i.e. it was published earliest, although names may be conserved if they have been very widely used. Validly published names other than the correct name are called synonyms. Since taxonomists may disagree as to the circumscription, position or rank of a taxon, there can be more than one correct name for a particular plant. These may also be called synonyms.

In zoological nomenclature, author citation refers to listing the person who first makes a scientific name of a taxon available. This is done in a scientific publication while fulfilling the formal requirements under the International Code of Zoological Nomenclature, hereinafter termed "the Code". According to the Code, "the name of the author does not form part of the name of a taxon and its citation is optional, although customary and often advisable", however Recommendation 51A suggests: "The original author and date of a name should be cited at least once in each work dealing with the taxon denoted by that name. This is especially important in distinguishing between homonyms and in identifying species-group names which are not in their original combinations". For the purpose of information retrieval, the author citation and year appended to the scientific name, e.g. genus-species-author-year, genus-author-year, family-author-year, etc., is often considered a "de facto" unique identifier, although for a number of reasons discussed below, this usage may often be imperfect.

In zoological nomenclature, the valid name of a taxon is the zoological name that is to be used for that taxon following the rules in the International Code of Zoological Nomenclature (ICZN). In other words: a valid name is the correct zoological name of a taxon.

In biological classification, circumscriptional names are taxon names that are not ruled by ICZN and are defined by the particular set of members included. Circumscriptional names are used mainly for taxa above family-group level, but can be also used for taxa of any ranks, as well as for rank-less taxa.

Open nomenclature is a vocabulary of partly informal terms and signs in which a taxonomist may express remarks about their own material. This is in contrast to synonymy lists, in which a taxonomist may express remarks on the work of others. Commonly such remarks take the form of abbreviated taxonomic expressions in biological classification.

This is a list of terms and symbols used in scientific names for organisms, and in describing the names. For proper parts of the names themselves, see glossary of scientific names. Note that many of the abbreviations are used with or without a stop.


  1. ICN, "Glossary", entry for "synonym"
  2. ICZN, "Glossary", entry for "synonym"
  3. ICN, Appendix IV
  4. Definition of synonym from Oxford Dictionaries Online , retrieved 2011-11-28
  5. BirdLife International (2017). " Bubo scandiacus". IUCN Red List of Threatened Species . 2017: e.T22689055A119342767. Retrieved 10 December 2017.CS1 maint: Uses authors parameter (link)
  6. ICZN, Art. 61.3
  7. ICZN, Art. 61.3.1
  8. ICZN, Art. 61.3.3
  9. p. 43 in Beck, H. 1837. Index molluscorum præsentis ævi musei principis augustissimi Christiani Frederici. – pp. 1–100 [1837], 101–124 [1838]. Hafniæ.
  10. ICZN, Art. 23.9 "reversal of precedence"
  11. Falkner, G., Ripken, T. E. J. & Falkner, M. 2002. Mollusques continentaux de France. Liste de référence annotée et bibliographie. – pp. [1–2], 1–350, [1–3]. Paris.
  12. ICN, Recommendation 50D
  13. Matthews, S. C. (1973), "Notes on open nomenclature and synonymy lists" (PDF), Palaeontology , 16: 713–719.
  14. Berendsohn, W. G. (1995), "The concept of "potential taxa" in databases" (PDF), Taxon, 44 (2): 207–212, doi:10.2307/1222443, JSTOR   1222443.