Genus ( / ˈ dʒ iː n ə s / ; pl. : genera / ˈ dʒ ɛ n ər ə / ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses . In binomial nomenclature , the genus name forms the first part of the binomial species name for each species within the genus.
67-408: See text . Lomariopsis is the type genus of the fern family Lomariopsidaceae . One economically important species exists via the freshwater aquarium plant trade, having only just been introduced in 2001 as an aquatic gametophyte form; most commonly known as " süsswassertang " (German for "freshwater seaweed"), this plant was initially believed to be some sort of liverwort . However, it
134-472: A set that includes some organisms and excludes others, based on a detailed published description (for example a species description ) and on the provision of type material, which is usually available to scientists for examination in a major museum research collection, or similar institution. According to a precise set of rules laid down in the International Code of Zoological Nomenclature (ICZN) and
201-557: A species : see Botanical name and Specific name (zoology) . The rules for the scientific names of organisms are laid down in the nomenclature codes , which allow each species a single unique name that, for animals (including protists ), plants (also including algae and fungi ) and prokaryotes ( bacteria and archaea ), is Latin and binomial in form; this contrasts with common or vernacular names , which are non-standardized, can be non-unique, and typically also vary by country and language of usage. Except for viruses ,
268-407: A clonotype. In zoological nomenclature , the type of a species or subspecies is a specimen or series of specimens. The type of a genus or subgenus is a species. The type of a suprageneric taxon (e.g., family, etc.) is a genus. Names higher than superfamily rank do not have types. A "name-bearing type" is a specimen or image that "provides the objective standard of reference whereby the application of
335-414: A diagnosis (typically, a discussion of similarities to and differences from closely related species), and an indication of where the type specimen or specimens are deposited for examination. The geographical location where a type specimen was originally found is known as its type locality . In the case of parasites, the term type host (or symbiotype) is used to indicate the host organism from which
402-400: A group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to anchor or centralizes the defining features of that particular taxon . In older usage (pre-1900 in botany), a type was a taxon rather than a specimen. A taxon is a scientifically named grouping of organisms with other like organisms,
469-643: A later homonym of a validly published name is a nomen illegitimum or nom. illeg. ; for a full list refer to the International Code of Nomenclature for algae, fungi, and plants and the work cited above by Hawksworth, 2010. In place of the "valid taxon" in zoology, the nearest equivalent in botany is " correct name " or "current name" which can, again, differ or change with alternative taxonomic treatments or new information that results in previously accepted genera being combined or split. Prokaryote and virus codes of nomenclature also exist which serve as
536-621: A long time and redescribed as new by a range of subsequent workers, or if a range of genera previously considered separate taxa have subsequently been consolidated into one. For example, the World Register of Marine Species presently lists 8 genus-level synonyms for the sperm whale genus Physeter Linnaeus, 1758, and 13 for the bivalve genus Pecten O.F. Müller, 1776. Within the same kingdom, one generic name can apply to one genus only. However, many names have been assigned (usually unintentionally) to two or more different genera. For example,
603-410: A lot of small plants), dead and kept safe, "curated", in a herbarium (or the equivalent for fungi). Examples of where an illustration may serve as a type include: A type does not determine the circumscription of the taxon. For example, the common dandelion is a controversial taxon: some botanists consider it to consist of over a hundred species, and others regard it as a single species. The type of
670-475: A new generic name; the old generic name passes into synonymy and is abandoned unless there is a pressing need to make an exception (decided case-by-case, via petition to the International Commission on Zoological Nomenclature). A type genus is a genus from which the name of a family or subfamily is formed. As with type species, the type genus is not necessarily the most representative but is usually
737-535: A part of it that has been stolen, or improperly relocated. Type illustrations have also been used by zoologists, as in the case of the Réunion parakeet , which is known only from historical illustrations and descriptions. Recently, some species have been described where the type specimen was released alive back into the wild, such as the Bulo Burti boubou (a bushshrike ), described as Laniarius liberatus , in which
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#1732883636280804-403: A passing remark on Linnaeus's contributions, "Linnaeus himself, must stand as the type of his Homo sapiens. He justified his choice by noting that the specimen that Linnaeus, who wrote his own autobiography five times, had most studied was probably himself. This sufficiently and correctly designated Linnaeus to be the lectotype for Homo sapiens . It has also been suggested that Edward Cope
871-409: A reference for designating currently accepted genus names as opposed to others which may be either reduced to synonymy, or, in the case of prokaryotes, relegated to a status of "names without standing in prokaryotic nomenclature". An available (zoological) or validly published (botanical) name that has been historically applied to a genus but is not regarded as the accepted (current/valid) name for
938-405: A scientific name to a specific operational taxonomic unit . Type specimens are theoretically even allowed to be aberrant or deformed individuals or color variations, though this is rarely chosen to be the case, as it makes it hard to determine to which population the individual belonged. The usage of the term type is somewhat complicated by slightly different uses in botany and zoology . In
1005-453: A single type specimen, a holotype, was often not designated. Also, types were not always carefully preserved, and intervening events such as wars and fires have resulted in the destruction of the original type material. The validity of a species name often rests upon the availability of original type specimens; or, if the type cannot be found, or one has never existed, upon the clarity of the description. The ICZN has existed only since 1961 when
1072-427: A taxon; however, the names published in suppressed works are made unavailable via the relevant Opinion dealing with the work in question. In botany, similar concepts exist but with different labels. The botanical equivalent of zoology's "available name" is a validly published name . An invalidly published name is a nomen invalidum or nom. inval. ; a rejected name is a nomen rejiciendum or nom. rej. ;
1139-455: A total of c. 520,000 published names (including synonyms) as at end 2019, increasing at some 2,500 published generic names per year. "Official" registers of taxon names at all ranks, including genera, exist for a few groups only such as viruses and prokaryotes, while for others there are compendia with no "official" standing such as Index Fungorum for fungi, Index Nominum Algarum and AlgaeBase for algae, Index Nominum Genericorum and
1206-410: A type. Describing species and appointing type specimens is part of scientific nomenclature and alpha taxonomy . When identifying material, a scientist attempts to apply a taxon name to a specimen or group of specimens based on their understanding of the relevant taxa, based on (at least) having read the type description(s), preferably also based on an examination of all the type material of all of
1273-443: Is a specimen later selected to serve as the single type specimen for species originally described from a set of syntypes . In zoology, a lectotype is a kind of name-bearing type . When a species was originally described on the basis of a name-bearing type consisting of multiple specimens, one of those may be designated as the lectotype. Having a single name-bearing type reduces the potential for confusion, especially considering that it
1340-504: Is a specimen of a kind of bird commonly known as the spotted harrier , which currently bears the scientific name Circus assimilis . This particular specimen is the holotype for that species; the name Circus assimilis refers, by definition, to the species of that particular specimen. That species was named and described by Jardine and Selby in 1828, and the holotype was placed in the museum collection so that other scientists might refer to it as necessary. At least for type specimens there
1407-456: Is any additional specimen from among a set of syntypes after a lectotype has been designated from among them. These are not name-bearing types. A special case in Protistans where the type consists of two or more specimens of "directly related individuals" within a preparation medium such as a blood smear. The terms parahapantotype and lectohapantotype refer to type preparations additional to
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#17328836362801474-425: Is clearly designated in the original description, this specimen is known as the holotype of that species. The holotype is typically placed in a major museum, or similar well-known public collection, so that it is freely available for later examination by other biologists. When the original description designated a holotype, there may be additional specimens that the author designates as additional representatives of
1541-503: Is closely allied to Lomariopsis lineata , but has not yet been named as a distinct species. As of February 2020, the Checklist of Ferns and Lycophytes of the World recognized the following species: This Polypodiales -related article is a stub . You can help Misplaced Pages by expanding it . Type (biology) In biology , a type is a particular specimen (or in some cases
1608-536: Is discouraged by both the International Code of Zoological Nomenclature and the International Code of Nomenclature for algae, fungi, and plants , there are some five thousand such names in use in more than one kingdom. For instance, A list of generic homonyms (with their authorities), including both available (validly published) and selected unavailable names, has been compiled by the Interim Register of Marine and Nonmarine Genera (IRMNG). The type genus forms
1675-463: Is no requirement for a "typical" individual to be used. Genera and families , particularly those established by early taxonomists, tend to be named after species that are more "typical" for them, but here too this is not always the case and due to changes in systematics cannot be. Hence, the term name-bearing type or onomatophore is sometimes used, to denote the fact that biological types do not define "typical" individuals or taxa , but rather fix
1742-454: Is not uncommon for a series of syntypes to contain specimens of more than one species. Formally, Carl Linnaeus is the lectotype for Homo sapiens , designated in 1959. He published the first book considered to be part of taxonomical nomenclature, the 10th edition of Systema Naturae, which included the first description of Homo sapiens and determined all valid syntypes for the species. Crucially, in 1959, Professor William Stearne wrote in
1809-411: Is one of many species that are based on illustrations by Albertus Seba (1734). An ergatotype is a specimen selected to represent a worker member in hymenopterans which have polymorphic castes. A hypotype is a specimen whose details have previously been published that is used in a supplementary figure or description of the species. The term " kleptotype " informally refers to a type specimen or
1876-460: Is somewhat arbitrary. Although all species within a genus are supposed to be "similar", there are no objective criteria for grouping species into genera. There is much debate among zoologists about whether enormous, species-rich genera should be maintained, as it is extremely difficult to come up with identification keys or even character sets that distinguish all species. Hence, many taxonomists argue in favor of breaking down large genera. For instance,
1943-474: Is the type species , and the generic name is permanently associated with the type specimen of its type species. Should the specimen turn out to be assignable to another genus, the generic name linked to it becomes a junior synonym and the remaining taxa in the former genus need to be reassessed. In zoological usage, taxonomic names, including those of genera, are classified as "available" or "unavailable". Available names are those published in accordance with
2010-485: Is the lectotype for Homo sapiens , based on the 1994 reporting by Louie Psihoyos of an unpublished proposal by Bob Bakker to do so. However, this designation is invalid both because Edward Cope was not one of the specimens described in Systema Naturae 10th Ed., and therefore not being a syntype is not eligible, and because Stearne's designation in 1959 has seniority and invalidates future designations. A paralectotype
2077-462: The International Code of Nomenclature for algae, fungi, and plants (ICN), the scientific name of every taxon is almost always based on one particular specimen , or in some cases specimens. Types are of great significance to biologists, especially to taxonomists . Types are usually physical specimens that are kept in a museum or herbarium research collection, but failing that, an image of an individual of that taxon has sometimes been designated as
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2144-687: The PhyloCode , type-based definitions are replaced by phylogenetic definitions . In some older taxonomic works the word "type" has sometimes been used differently. The meaning was similar in the first Laws of Botanical Nomenclature , but has a meaning closer to the term taxon in some other works: Ce seul caractère permet de distinguer ce type de toutes les autres espèces de la section. ... Après avoir étudié ces diverses formes, j'en arrivai à les considérer comme appartenant à un seul et même type spécifique. Translation: This single character permits [one to] distinguish this type from all other species of
2211-621: The International Code of Zoological Nomenclature ; the earliest such name for any taxon (for example, a genus) should then be selected as the " valid " (i.e., current or accepted) name for the taxon in question. Consequently, there will be more available names than valid names at any point in time; which names are currently in use depending on the judgement of taxonomists in either combining taxa described under multiple names, or splitting taxa which may bring available names previously treated as synonyms back into use. "Unavailable" names in zoology comprise names that either were not published according to
2278-799: The International Plant Names Index for plants in general, and ferns through angiosperms, respectively, and Nomenclator Zoologicus and the Index to Organism Names for zoological names. Totals for both "all names" and estimates for "accepted names" as held in the Interim Register of Marine and Nonmarine Genera (IRMNG) are broken down further in the publication by Rees et al., 2020 cited above. The accepted names estimates are as follows, broken down by kingdom: The cited ranges of uncertainty arise because IRMNG lists "uncertain" names (not researched therein) in addition to known "accepted" names;
2345-552: The nomenclature code applied to the organism in question, a type can be a specimen, a culture, an illustration , or (under the bacteriological code) a description. Some codes consider a subordinate taxon to be the type, but under the botanical code, the type is always a specimen or illustration. For example, in the research collection of the Natural History Museum in London, there is a bird specimen numbered 1886.6.24.20. This
2412-404: The platypus belongs to the genus Ornithorhynchus although George Shaw named it Platypus in 1799 (these two names are thus synonyms ) . However, the name Platypus had already been given to a group of ambrosia beetles by Johann Friedrich Wilhelm Herbst in 1793. A name that means two different things is a homonym . Since beetles and platypuses are both members of the kingdom Animalia,
2479-469: The French botanist Joseph Pitton de Tournefort (1656–1708) is considered "the founder of the modern concept of genera". The scientific name (or the scientific epithet) of a genus is also called the generic name ; in modern style guides and science, it is always capitalised. It plays a fundamental role in binomial nomenclature , the system of naming organisms , where it is combined with the scientific name of
2546-442: The base for higher taxonomic ranks, such as the family name Canidae ("Canids") based on Canis . However, this does not typically ascend more than one or two levels: the order to which dogs and wolves belong is Carnivora ("Carnivores"). The numbers of either accepted, or all published genus names is not known precisely; Rees et al., 2020 estimate that approximately 310,000 accepted names (valid taxa) may exist, out of
2613-515: The earliest described, largest or best-known genus. It is not uncommon for the name of a family to be based upon the name of a type genus that has passed into synonymy; the family name does not need to be changed in such a situation. Genera The composition of a genus is determined by taxonomists . The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including
2680-467: The essential characteristics of the genus to which it belongs, but this is subjective and, ultimately, technically irrelevant, as it is not a requirement of the Code. If the type species proves, upon closer examination, to belong to a pre-existing genus (a common occurrence), then all of the constituent species must be either moved into the pre-existing genus or disassociated from the original type species and given
2747-432: The first edition of the Code was published. The ICZN does not always demand a type specimen for the historical validity of a species, and many "type-less" species do exist. The current edition of the Code, Article 75.3, prohibits the designation of a neotype unless there is "an exceptional need" for "clarifying the taxonomic status" of a species (Article 75.2). There are many other permutations and variations on terms using
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2814-446: The form "author, year" in zoology, and "standard abbreviated author name" in botany. Thus in the examples above, the genus Canis would be cited in full as " Canis Linnaeus, 1758" (zoological usage), while Hibiscus , also first established by Linnaeus but in 1753, is simply " Hibiscus L." (botanical usage). Each genus should have a designated type , although in practice there is a backlog of older names without one. In zoology, this
2881-727: The generic name (or its abbreviated form) still forms the leading portion of the scientific name, for example, Canis lupus lupus for the Eurasian wolf subspecies, or as a botanical example, Hibiscus arnottianus ssp. immaculatus . Also, as visible in the above examples, the Latinised portions of the scientific names of genera and their included species (and infraspecies, where applicable) are, by convention, written in italics . The scientific names of virus species are descriptive, not binomial in form, and may or may not incorporate an indication of their containing genus; for example,
2948-469: The hapantotype and designated by the describing author. As with other type designations the use of the prefix "Neo-", such as Neohapantotype , is employed when a replacement for the original hapantotype is designated, or when an original description did not include a designated type specimen. An illustration on which a new species or subspecies was based. For instance, the Burmese python, Python bivittatus ,
3015-432: The idea that a newly defined genus should fulfill these three criteria to be descriptively useful: Moreover, genera should be composed of phylogenetic units of the same kind as other (analogous) genera. The term "genus" comes from Latin genus , a noun form cognate with gignere ('to bear; to give birth to'). The Swedish taxonomist Carl Linnaeus popularized its use in his 1753 Species Plantarum , but
3082-628: The largest component, with 23,236 ± 5,379 accepted genus names, of which 20,845 ± 4,494 are angiosperms (superclass Angiospermae). By comparison, the 2018 annual edition of the Catalogue of Life (estimated >90% complete, for extant species in the main) contains currently 175,363 "accepted" genus names for 1,744,204 living and 59,284 extinct species, also including genus names only (no species) for some groups. The number of species in genera varies considerably among taxonomic groups. For instance, among (non-avian) reptiles , which have about 1180 genera,
3149-403: The most (>300) have only 1 species, ~360 have between 2 and 4 species, 260 have 5–10 species, ~200 have 11–50 species, and only 27 genera have more than 50 species. However, some insect genera such as the bee genera Lasioglossum and Andrena have over 1000 species each. The largest flowering plant genus, Astragalus , contains over 3,000 species. Which species are assigned to a genus
3216-408: The name Taraxacum officinale is the same whether the circumscription of the species includes all those small species ( Taraxacum officinale is a "big" species) or whether the circumscription is limited to only one small species among the other hundred ( Taraxacum officinale is a "small" species). The name Taraxacum officinale is the same and the type of the name is the same, but the extent to which
3283-517: The name actually applies varies greatly. Setting the circumscription of a taxon is done by a taxonomist in a publication. Miscellaneous notes: The ICN provides a listing of the various kinds of types (article 9 and the Glossary), the most important of which is the holotype. These are The word "type" appears in botanical literature as a part of some older terms that have no status under the ICN : for example
3350-428: The name could not be used for both. Johann Friedrich Blumenbach published the replacement name Ornithorhynchus in 1800. However, a genus in one kingdom is allowed to bear a scientific name that is in use as a generic name (or the name of a taxon in another rank) in a kingdom that is governed by a different nomenclature code. Names with the same form but applying to different taxa are called "homonyms". Although this
3417-474: The name of a nominal taxon can be determined." Although in reality biologists may examine many specimens (when available) of a new taxon before writing an official published species description, nonetheless, under the formal rules for naming species (the International Code of Zoological Nomenclature), a single type must be designated, as part of the published description. A type description must include
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#17328836362803484-535: The original author never cited a specimen. A syntype is any one of two or more specimens that is listed in a species description where no holotype was designated; historically, syntypes were often explicitly designated as such, and under the present ICZN this is a requirement, but modern attempts to publish species description based on syntypes are generally frowned upon by practicing taxonomists, and most are gradually being replaced by lectotypes. Those that still exist are still considered name-bearing types. A lectotype
3551-459: The provisions of the ICZN Code, e.g., incorrect original or subsequent spellings, names published only in a thesis, and generic names published after 1930 with no type species indicated. According to "Glossary" section of the zoological Code, suppressed names (per published "Opinions" of the International Commission of Zoological Nomenclature) remain available but cannot be used as the valid name for
3618-409: The relevant taxa. If there is more than one named type that all appear to be the same taxon, then the oldest name takes precedence and is considered to be the correct name of the material in hand. If on the other hand, the taxon appears never to have been named at all, then the scientist or another qualified expert picks a type specimen and publishes a new name and an official description. Depending on
3685-504: The same species, termed paratypes. These are not name-bearing types . An allotype is a specimen of the opposite sex to the holotype, designated from among paratypes. The word was also formerly used for a specimen that shows features not seen in the holotype of a fossil. The term is not regulated by the ICZN . A neotype is a specimen later selected to serve as the single type specimen when an original holotype has been lost or destroyed or where
3752-406: The section ... After studying the diverse forms, I came to consider them as belonging to the one and the same specific type. In botanical nomenclature , a type ( typus , nomenclatural type ), "is that element to which the name of a taxon is permanently attached." (article 7.2) In botany, a type is either a specimen or an illustration. A specimen is a real plant (or one or more parts of a plant or
3819-405: The species description included DNA sequences from blood and feather samples. Assuming there is no future question as to the status of such a species, the absence of a type specimen does not invalidate the name, but it may be necessary for the future to designate a neotype for such a taxon, should any questions arise. However, in the case of the bushshrike, ornithologists have argued that the specimen
3886-497: The specific name particular to the wolf. A botanical example would be Hibiscus arnottianus , a particular species of the genus Hibiscus native to Hawaii. The specific name is written in lower-case and may be followed by subspecies names in zoology or a variety of infraspecific names in botany . When the generic name is already known from context, it may be shortened to its initial letter, for example, C. lupus in place of Canis lupus . Where species are further subdivided,
3953-412: The standard format for a species name comprises the generic name, indicating the genus to which the species belongs, followed by the specific epithet, which (within that genus) is unique to the species. For example, the gray wolf 's scientific name is Canis lupus , with Canis ( Latin for 'dog') being the generic name shared by the wolf's close relatives and lupus (Latin for 'wolf') being
4020-414: The suffix "-type" (e.g., allotype , cotype, topotype , generitype , isotype , isoneotype, isolectotype, etc.) but these are not formally regulated by the Code, and a great many are obsolete and/or idiosyncratic. However, some of these categories can potentially apply to genuine type specimens, such as a neotype; e.g., isotypic/topotypic specimens are preferred to other specimens, when they are available at
4087-403: The taxon is termed a synonym ; some authors also include unavailable names in lists of synonyms as well as available names, such as misspellings, names previously published without fulfilling all of the requirements of the relevant nomenclatural code, and rejected or suppressed names. A particular genus name may have zero to many synonyms, the latter case generally if the genus has been known for
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#17328836362804154-415: The time a neotype is chosen (because they are from the same time and/or place as the original type). A topotype is a specimen that was obtained from the same location that the original type specimen came from. The term fixation is used by the Code for the declaration of a name-bearing type, whether by original or subsequent designation. Each genus must have a designated type species (the term "genotype"
4221-406: The type specimen was obtained. Zoological collections are maintained by universities and museums. Ensuring that types are kept in good condition and made available for examination by taxonomists are two important functions of such collections. And, while there is only one holotype designated, there can be other "type" specimens, the following of which are formally defined: When a single specimen
4288-566: The values quoted are the mean of "accepted" names alone (all "uncertain" names treated as unaccepted) and "accepted + uncertain" names (all "uncertain" names treated as accepted), with the associated range of uncertainty indicating these two extremes. Within Animalia, the largest phylum is Arthropoda , with 151,697 ± 33,160 accepted genus names, of which 114,387 ± 27,654 are insects (class Insecta). Within Plantae, Tracheophyta (vascular plants) make up
4355-429: The virus species " Salmonid herpesvirus 1 ", " Salmonid herpesvirus 2 " and " Salmonid herpesvirus 3 " are all within the genus Salmonivirus ; however, the genus to which the species with the formal names " Everglades virus " and " Ross River virus " are assigned is Alphavirus . As with scientific names at other ranks, in all groups other than viruses, names of genera may be cited with their authorities, typically in
4422-493: Was a rare and hitherto unknown color morph of a long-known species, using only the available blood and feather samples. While there is still some debate on the need to deposit actual killed individuals as type specimens, it can be observed that given proper vouchering and storage, tissue samples can be just as valuable should dispute about the validity of a species arise. The various types listed above are necessary because many species were described one or two centuries ago, when
4489-420: Was once used for this but has been abandoned because the word has become much better known as the term for a different concept in genetics ). The description of a genus is usually based primarily on its type species, modified and expanded by the features of other included species. The generic name is permanently associated with the name-bearing type of its type species. Ideally, a type species best exemplifies
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