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 (which shares the acronym "ICZN"). The rules principally regulate:
Zoological nomenclature is independent of other systems of nomenclature, for example botanical nomenclature. This implies that animals can have the same generic names as plants.
The rules and recommendations have one fundamental aim: to provide the maximum universality and continuity in the naming of all animals, except where taxonomic judgment dictates otherwise. The code is meant to guide only the nomenclature of animals, while leaving zoologists freedom in classifying new taxa.
In other words, whether a species itself is or is not a recognized entity is a subjective decision, but what name should be applied to it is not. The code applies only to the latter. A new animal name published without adherence to the code may be deemed simply "unavailable" if it fails to meet certain criteria, or fall entirely out of the province of science (e.g., the "scientific name" for the Loch Ness Monster).
The rules in the code determine what names are valid for any taxon in the family group, genus group, and species group. It has additional (but more limited) provisions on names in higher ranks. The code recognizes no case law. Any dispute is decided first by applying the code directly, and not by reference to precedent.
The code is also retroactive or retrospective, which means that previous editions of the code, or previous other rules and conventions have no force any more today, and the nomenclatural acts published 'back in the old times' must be evaluated only under the present edition of the code. In cases of disputes concerning the interpretation, the usual procedure is to consult the French Code, lastly a case can be brought to the commission who has the right to publish a final decision.
In regulating the names of animals it holds by six central principles, which were first set out (as principles) in the third edition of the code (1985):
This is the principle that the scientific name of a species, and not of a taxon at any other rank, is a combination of two names; the use of a trinomen for the name of a subspecies and of uninominal names for taxa above the species group is in accord with this principle.
This means that in the system of nomenclature for animals, the name of a species is composed of a combination of a generic name and a specific name; together they make a "binomen". No other rank can have a name composed of two names. Examples:
In botanical nomenclature, the equivalent for "binominal nomenclature" is "binary nomenclature" (or sometimes "binomial nomenclature").
This is the principle that the correct formal scientific name for an animal taxon, the valid name, correct to use, is the oldest available name that applies to it. It is the most important principle—the fundamental guiding precept that preserves zoological nomenclature stability. It was first formulated in 1842 by a committee appointed by the British Association to consider the rules of zoological nomenclature. Hugh Edwin Strickland wrote the committee's report.
There are approximately 2-3 million cases of this kind for which this principle is applied in zoology.
The principle of coordination is that within the family group, genus group and species group, a name established for a taxon at any rank in the group is simultaneously established with the same author and date for taxa based on the same name-bearing type at other ranks in the corresponding group. In other words, publishing a new zoological name automatically and simultaneously establishes all corresponding names in the relevant other ranks with the same type.
In the species-group, publishing a species name (the binomen) Giraffa camelopardalis Linnaeus, 1758 also establishes the subspecies name (the trinomen) Giraffa camelopardalis camelopardalis Linnaeus, 1758. The same applies to the name of a subspecies; this establishes the corresponding species name.
In the genus-group, similarly, publishing the name of a genus also establishes the corresponding name of a subgenus (or vice versa): genus Giraffa Linnaeus, 1758 and subgenus Giraffa (Giraffa) Linnaeus, 1758.
In the family-group, publication of the name of a family, subfamily, superfamily (or any other such rank) also establishes the names in all the other ranks in the family group (family Giraffidae, superfamily Giraffoidea, subfamily Giraffinae).
Author citations for such names (for example a subgenus) are the same as for the name actually published (for example a genus). It is immaterial if there is an actual taxon to which the automatically established name applies; if ever such a taxon is recognised, there is a name available for it.
This is the principle that in cases of conflicts between simultaneously published divergent acts, the first subsequent author can decide which has precedence. It supplements the principle of priority, which states that the first published name takes precedence. The principle of the first reviser deals with situations that cannot be resolved by priority. These items may be two or more different names for the same taxon, two or more names with the same spelling used for different taxa, two or more different spellings of a particular name, etc. In such cases, the first subsequent author who deals with the matter and chooses and publishes the decision in the required manner is the first reviser, and is to be followed.
Linnæus 1758 established Strix scandiaca and Strix noctua (Aves), for which he gave different descriptions and referred to different types, but both taxa later turned out to refer to the same species, the snowy owl. The two names are subjective synonyms. Lönnberg 1931 acted as first reviser, cited both names and selected Strix scandiaca to have precedence.
This is the principle that the name of each taxon must be unique. Consequently, a name that is a junior homonym of another name must not be used as a valid name.
It means that any one animal name, in one particular spelling, may be used only once (within its group). This is usually the first-published name; any later name with the same spelling (a homonym) is barred from being used. The principles of priority and first reviser apply here. For family-group names the termination (which is rank-bound) is not taken into account.
Genera are homonyms only if exactly the same — a one-letter difference is enough to distinguish them.
In species, there is a difference between primary and secondary homonyms. There can also be double homonyms (same genus and species). A slight difference in spelling is tolerated if Article 58 applies.
Primary homonyms are those with the same genus and same species in their original combination. The difference between a primary junior homonym and a subsequent use of a name is undefined, but it is commonly accepted that if the name referred to another species or form, and if there is in addition no evidence the author knew that the name was previously used, it is considered as a junior homonym.
Secondary homonyms can be produced if taxa with the same specific name but different original genus are later classified in the same genus (Art. 57.3, 59). A secondary synonym is only a temporary state, it is only effective in this classification. If another classification is applied, the secondary homonymy may not be produced, and the involved name can be used again (Art. 59.1). A name does not become unavailable or unusable if it was once in the course of history placed in such a genus where it produced a secondary homonymy with another name. This is one of the rare cases where a zoological species does not have a stable specific name and a unique species-author-year combination, it can have two names at the same time.
Article 59.3 states that in exceptional cases, junior secondary homonyms replaced before 1961 by substitute names can become invalid, "...unless the substitute name is not in use," an exception of the exception. However, the ICZN Code does not give an example for such a case. It seems that this passage in the ICZN Code is widely ignored. It also does not define what the expression "is not in use" should mean.
Double homonymy (genus and species) is no homonymy: if the genera are homonyms and belong to different animal groups, the same specific names can be used in both groups.
For disambiguating one genus-group name from its homonym, it is important to cite author and year. Citing the author alone is often not sufficient.
The name Ansa can only be used for a lepidopteran taxon. If that name cannot be used (for example because an older name established prior to 1858 takes precedence), this does not mean that the 1868 name can be used for a hemipteran genus. The only option to use the 1868 name for the hemipteran taxon is to get the 1858 name officially suppressed by the commission.
In some cases, the same genus-group or species-group name was published in the same year by the same author. In these cases it is useful to cite the page where the name was established.
There are cases where two homonyms were established by the same author in the same year on the same page:
Animal, plant, and fungi nomenclature are entirely independent from each other. The most evident shortcoming of this situation (for their use in biodiversity informatics) is that the same generic name can be used simultaneously for animals and plants. For this kind of homonym the expression "hemihomonym" is sometimes used. Far more than 1000 such names are known.
For names above the family level, the principle of homonymy does not apply.
Homonyms occur relatively rarely in families (only if generic names are identical or very similar and adding an ending "-idae" produces identical results). Discovering such a homonymy usually produces the same problems as if there were no rules: conflicts between entirely independent and unconnected groups of taxonomists working in different animal groups. Very often the Commission must be asked to take a decision.
This is the principle that each nominal taxon in the family group, genus group, or species group has—actually or potentially—a name-bearing type fixed that provides the objective standard of reference that determines what the name applies to.
This means that any named taxon has a name-bearing type, which allows the objective application of that name. Any family-group name must have a type genus, any genus-group name must have a type species, and any species-group name can (not must) have one or more type specimens (holotype, lectotype, neotype, syntypes, or others), usually deposited in a museum collection. The type genus for a family-group name is simply the genus that provided the stem to which was added the ending "-idae" (for families). Example:
The type species for a genus-group name is more complicated and follows exactly defined provisions in articles 67-69. Type species are very important, and no general zoological database has recorded the type species for all genera. Except in fishes and some minor groups, type species are rarely reliably recorded in online animal databases. In 60% of the cases the type species can be determined in the original publication. The type species is always the original name of the taxon (and not the currently used combination).
Designation and fixation have different meanings. A designation is the proposal of the type species. It is not necessary to have spelled the name of the genus or species correctly with correct authors (articles 67.2.1, 67.6, 67.7), type species are always the correctly spelled name. If the designation is valid, the type species is fixed.
A designation can also be invalid and ineffective—for example—if the genus had already a previously fixed type species, or if a type species was proposed that was not originally included, or contradicted the description or figure for a genus for which no species had originally been included.
There are various possible modes of type species designation. This is their order of legal importance, with approximate proportions of occurrence[note 2] and examples:
A species-group name can have a name-bearing type specimen, but this is not a requirement. In many cases species-group names have no type specimens, or they are lost. In those cases the application of the species-group name is usually based on common acceptance. If there is no common acceptance, there are provisions in the Code to fix a name-bearing type specimen that is binding for users of that name. Fixing such a name-bearing type should only be done if this is taxonomically necessary (articles 74.7.3, 75.2, 75.3).
Links to the separate articles:
The code divides names in the following manner:
The names above the family group are regulated only as to the requirements for publication; there is no restriction to the number of ranks and the use of names is not restricted by priority.
The names in the family, genus, and species groups are fully regulated by the provisions in the code. There is no limitation to the number of ranks allowed in the family group. The genus group has only two ranks: genus and subgenus. The species group has only two ranks: species and subspecies.
In the species group gender agreement applies. The name of a species, in two parts, a binomen, say, Loxodonta africana, and of a subspecies, in three parts, a trinomen, say Canis lupus albus, is in the form of a Latin phrase, and must be grammatically correct Latin. If the second part, the specific name (or the third part, the subspecific name) is adjectival in nature, its ending must agree in gender with the name of the genus. If it is a noun, or an arbitrary combination of letters, this does not apply.
If a species is moved, therefore, the spelling of an ending may need to change. If Gryllus migratorius is moved to the genus Locusta, it becomes Locusta migratoria. Confusion over Latin grammar has led to many incorrectly formed names appearing in print. An automated search may fail to find all the variant spellings of a given name (e.g., the spellings atra and ater may refer to the same species).
Many laymen, and some scientists, object to continued adherence to this rule, especially those who work with butterflies and moths. This is for historical reasons. In 1758, Linnæus placed all butterflies in the genus Papilio, which, after a few decades, contained thousands of species. From the beginning, the gender of Papilio was unclear, undecided, and disputed. Some authors regarded it as masculine, others as feminine. Linnæus knew this problem and avoided any statement. All his 250 specific names in the genus Papilio were either nouns, indeclinable adjectives, or adjectives ending in -is (which can be masculine or feminine but not neuter). He did not use a single adjective ending in -us, -a, -um. P. Brown, Cramer, Fabricius, Fueßlin, Goeze, Poda and Schrank regarded Papilio as masculine, Ménétriés, Pontoppidan and most modern authors as feminine. In ICZN Opinion 278 from 1954, it was regarded as masculine. In many cases lepidopterists would not change the ending of a name as used by the author who established a name. So we find for example Papilio fuscus or Papilio macilentus, but also Papilio osmana and Papilio paradoxa. Only in a few cases are both versions found in the Web (an example is Papilio multicaudatus and Papilio multicaudata). This works also with other butterfly genera of which the gender is undisputed. Graphium appears neuter, but only the inconsistent versions Graphium angolanus and Graphium mandarinus are used, while Graphium sandawanum can only be found with a neuter specific name. Likewise, pairs are more frequently found in genera of which the gender is not obvious: Delias castaneus and Delias gigantea, Belenois albumaculatus and Belenois rubrosignata, Mylothris arabicus and Mylothris ruandana. Even in moths, such pairs occur: Xylophanes obscurus and Xylophanes turbata, Manduca boliviana and Manduca caribbeus, Sphinx caligineus and Sphinx formosana, Macroglossum albolineata and Macroglossum vicinum. It may also occur that a lepidopteran subspecies can have a different gender from the name of the species, as for example in Papilio multicaudata pusillus Austin & Emmel, 1998, and Papilio torquatus flavida Oberthür, 1879.
Written nomenclatural rules in zoology were compiled in various countries since the late 1830s, such as Merton's Rules and Strickland's codes going back to 1843. At the first and second International Zoological Congresses (Paris 1889, Moscow 1892) zoologists saw the need to establish commonly accepted international rules for all disciplines and countries to replace conventions and unwritten rules that varied across disciplines, countries, and languages.
Compiling "International Rules on Zoological Nomenclature" was first proposed in 1895 in Leiden (3rd International Congress for Zoology) and officially published in three languages in 1905 (French, English, German; only French was official). From then on, amendments and modifications were subsequently passed by various zoological congresses (Boston 1907, Graz 1910, Monaco 1913, Budapest 1927, Padua 1930, Paris 1948, Copenhagen 1953, and London 1958). These were only published in English, and can only be found in the reports of these congresses or other official publications.
The 1905 rules became increasingly outdated. They soon sold out, and it became increasingly difficult to obtain to a complete set of the Rules with all amendments. In Copenhagen 1953 the French and English texts of the rules were declared of equivalent official force, and a declaration was approved to prepare a new compilation of the rules. In 1958, an Editorial Committee in London elaborated a completely new version of the nomenclatural rules, which were finally published as the first edition of the ICZN Code on 9 November 1961.
The second edition of the code (only weakly modified) came in 1963. The last zoological congress to deal with nomenclatural problems took place in Monte Carlo 1972, since by then the official zoological organs no longer derived power from zoological congresses. The third edition of the code came out in 1985. The present edition is the 4th edition, effective since 2000. These code editions were elaborated on by editorial committees appointed by the International Commission on Zoological Nomenclature. The ICZN Commission takes its power from a general biological congress (IUBS, International Union of Biological Sciences). The editorial committee for the fourth edition was composed of seven persons. Such new editions of the ICZN Code are not democratically approved by those taxonomists who are forced to follow the code's provisions, neither do taxonomists have the right to vote for the members of the commission or the editorial committee.
As the commission may alter the code (by declarations and amendments) without issuing a new edition of the book, the current edition does not necessarily contain the actual provision that applies in a particular case. The Code consists of the original text of the fourth edition and Declaration 44. The code is published in an English and a French version; both versions are official and equivalent in force, meaning, and authority. This means that if something in the English code is unclear or its interpretation ambiguous, the French version is decisive, and if there is something unclear in the French code, the English version is decisive.
The rules in the code apply to all users of zoological names. However, its provisions can be interpreted, waived, or modified in their application to a particular case when strict adherence would cause confusion. Such exceptions are not made by an individual scientist, no matter how well-respected within the field, but only by the International Commission on Zoological Nomenclature, acting on behalf of all zoologists. The commission takes such action in response to proposals submitted to it.
The latest amendments enacted by the commission concern electronic publishing, which is now permitted for works published under an ISBN or ISSN after 2011 in a way that ensures registration with ZooBank as well as archival of multiple copies.
The ICZN is used by the scientific community worldwide. Changes are governed by guidelines in the code. Local changes, such as the changes proposed by the Turkish government, are not recognised by ICZN.
The current (fourth edition) code is cited in scientific papers as ICZN (1999) and in reference lists as:-
ICZN 1999. International Code of Zoological Nomenclature. Fourth Edition. The International Trust for Zoological Nomenclature, London, UK. 306 pp.
In zoology, an available name is a scientific name for a taxon of animals that has been published conforming to all the mandatory provisions of the International Code of Zoological Nomenclature for the establishment of a zoological name.
For a name to be available, there are a number of general requirements it must fulfill: it must use only the Latin alphabet, be published in a timely fashion by a reputable source, etc. In some rare cases, a name which does not meet these requirements may nevertheless be available, for historical reasons.An available name is not necessarily a valid name, because an available name may be in synonymy. However, a valid name must always be an available one.Conserved name
A conserved name or nomen conservandum (plural nomina conservanda, abbreviated as nom. cons.) 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".
The process for conserving botanical names is different from that for zoological names. Under the botanical code, names may also be "suppressed", nomen rejiciendum (plural nomina rejicienda or nomina utique rejicienda, abbreviated as nom. rej.), or rejected in favour of a particular conserved name, and combinations based on a suppressed name are also listed as “nom. rej.”.Form (zoology)
This article is not about formal zoological nomenclature; it describes terms that are sometimes used, but that have no standing under the ICZN.In zoology, the word "form" or forma (literally Latin for form) is a strictly informal term that is sometimes used to describe organisms. Under the International Code of Zoological Nomenclature the term has no standing (it is not accepted). In other words, although form names are Latin, and are sometimes wrongly appended to a binomial name, in a zoological context, forms have no taxonomic significance at all.Great evening bat
The great evening bat (Ia io) is the largest bat in the vesper bat family (Vespertilionidae) and the only living species in the genus Ia. It is common to Eastern and Southeastern Asia (China, India, Laos, Nepal, Thailand and Vietnam), mainly living in areas with limestone caves at altitudes of 400–1,700 metres (0.25–1.06 mi). Their roost sites have been found both near the cave entrances and up to 1.5 kilometres (0.93 mi) within the cave systems.The great evening bat reaches a length of 90 to 105 millimetres (3.5–4.1 in). It is colored brown on the top and grayish on the bottom. Average wingspan is .51 m (20 in) and it typically weighs 58 g (2.0 oz).Not much is known about its habits and behavior. The bat usually lives in small groups. Its food consists of insects, as with most vesper bats. The Asian great evening bat also sometimes feeds on small birds . The bat leaves its sleeping place already in the late afternoon for the search of food. During the winter months it may migrate to warmer regions.
The IUCN lists its conservation status as Least Concern. One of the threats to its survival in South Asia is human influence by habitat destruction; many caves have been turned into attractions. They have also been disturbed by farmers collecting their excrement. Also the excessive use of insecticides poses a threat to the great evening bats.At four letters, Ia io is tied with Yi qi for the shortest existing (and shortest possible) scientific name of any animal under the International Code of Zoological Nomenclature, and is one of very few scientific names composed solely of vowels .Holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several such, but explicitly designated as the holotype. Under the International Code of Zoological Nomenclature (ICZN), a holotype is one of several kinds of name-bearing types. In the International Code of Nomenclature for algae, fungi, and plants (ICN) and ICZN the definitions of types are similar in intent but not identical in terminology or underlying concept.
For example, the holotype for the butterfly Lycaeides idas longinus is a preserved specimen of that species, held by the Museum of Comparative Zoology at Harvard University. An isotype is a duplicate of the holotype and is often made for plants, where holotype and isotypes are often pieces from the same individual plant or samples from the same gathering.
A holotype is not necessarily "typical" of that taxon, although ideally it should be. Sometimes just a fragment of an organism is the holotype, particularly in the case of a fossil. For example, the holotype of Pelorosaurus humerocristatus (Duriatitan), a large herbivorous dinosaur from the early Jurassic period, is a fossil leg bone stored at the Natural History Museum in London. Even if a better specimen is subsequently found, the holotype is not superseded.Homonym (biology)
In biology, a homonym is a name for a taxon that is identical in spelling to another such name, that belongs to a different taxon.
The rule in the International Code of Zoological Nomenclature is that the first such name to be published is the senior homonym and is to be used (it is "valid"); any others are junior homonyms and must be replaced with new names. It is, however, possible that if a senior homonym is archaic, and not in "prevailing usage," it may be declared a nomen oblitum and rendered unavailable, while the junior homonym is preserved as a nomen protectum.
Cuvier proposed the genus Echidna in 1797 for the spiny anteater.
However, Forster had already published the name Echidna in 1777 for a genus of moray eels.
Forster's use thus has priority, with Cuvier's being a junior homonym.
Illiger published the replacement name Tachyglossus in 1811.Similarly, the International Code of Nomenclature for algae, fungi, and plants (ICN) specifies that the first published of two or more homonyms is to be used: a later homonym is "illegitimate" and is not to be used unless conserved (or sanctioned, in the case of fungi).
Example: the later homonym Myroxylon L.f. (1782), in the family Leguminosae, is conserved against the earlier homonym Myroxylon J.R.Forst. & G.Forst. (1775) (now called Xylosma, in the family Salicaceae).Ia (genus)
Ia is a genus of bat in the family Vespertilionidae. It belongs to the subfamily Vespertilioninae and has been placed in the tribe Vespertilionini. In the past, it has also been considered a synonym or subgenus of the genera Pipistrellus or Eptesicus, which used to contain many more species than they do now. Ia comprises a single living species, the great evening bat (I. io) of eastern and southeastern Asia, and one extinct fossil species, I. lanna, from the Miocene epoch in Thailand. Another living species, I. longimana, was recognized in the past, but it is no longer considered a valid species distinct from the great evening bat.
At two letters, Ia ties the bat-like dinosaur Yi for the shortest possible name of any animal genus under the International Code of Zoological Nomenclature.List of belemnite genera
This list of belemnite genera is an attempt to create a comprehensive listing of all genera that have ever been included in the extinct subclass Belemnoidea, excluding purely vernacular terms. The list includes all commonly accepted genera, as well as genera that are now considered invalid, doubtful (nomina dubia), or were not formally published (nomina nuda), as well as junior synonyms of more established names, and genera that are no longer considered belemites. Naming conventions and terminology follow the International Code of Zoological Nomenclature as indicated.
The list currently contains 100 generic names.Nomen oblitum
A nomen oblitum (Plural: nomina oblita; Latin for "forgotten name") is a technical term, used in zoological nomenclature, for a particular kind of disused scientific name.
In its present meaning, the nomen oblitum came into being with the fourth, 1999, edition of the International Code of Zoological Nomenclature. After 1 January 2000, a scientific name may be formally declared to be a nomen oblitum when it has been shown not to have been used as a valid name within the scientific community since 1899, and when it is either a senior synonym (there is also a more recent name which applies to the same taxon, and which is in common use) or a homonym (it is spelled the same as another name, which is in common use), and when the preferred junior synonym or homonym has been shown to be in wide use in 50 or more publications in the past few decades. Once a name has formally been declared to be a nomen oblitum, the disused name is to be 'forgotten'. By the same act, the next available name must be declared to be a nomen protectum; from then on, it takes precedence.An example is the case of the scientific name for the leopard shark. Despite the name Mustelus felis being the senior synonym, an error in recording the dates of publication resulted in the widespread use of Triakis semifasciata as the leopard shark's scientific name. After this long-standing error was discovered, T. semifasciata was made the valid name (as a nomen protectum) and Mustelis felis was declared invalid (as a nomen oblitum).Paratype
In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). Often there is more than one paratype. Paratypes are usually held in museum research collections.
The exact meaning of the term paratype when it is used in zoology is not the same as the meaning when it is used in botany. In both cases however, this term is used in conjunction with holotype.Subfamily
In biological classification, a subfamily (Latin: subfamilia, plural subfamiliae) is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoological names with "-inae".Subgenus
In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus.
In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the tiger cowry of the Indo-Pacific, Cypraea (Cypraea) tigris Linnaeus, which belongs to the subgenus Cypraea of the genus Cypraea. However, it is not mandatory, or even customary, when giving the name of a species, to include the subgeneric name.
In the International Code of Nomenclature for algae, fungi, and plants (ICNafp), the subgenus is one of the possible subdivisions of a genus. There is no limit to the number of divisions that are permitted within a genus by adding the prefix "sub-" or in other ways as long as no confusion can result. The secondary ranks of section and series are subordinate to subgenus. An example is Banksia subg. Isostylis, a subgenus of the large Australian genus Banksia. The ICNafp requires an explicit "connecting term" to indicate the rank of the division within the genus. Connecting terms are usually abbreviated, e.g. "subg." for "subgenus", and are not italicized.
In zoological nomenclature, when a genus is split into subgenus, the originally described population is retained as the "nominotypical subgenus" or "nominate subgenus", which repeats the same name as the genus. For example, Panthera (Panthera) pardus, a leopard. In botanical nomenclature, the same principle applies, although the terminology is different. Thus the subgenus that contains the original type of the genus Rhododendron is Rhododendron subg. Rhododendron. Such names are called "autonyms".Subspecies
In biological classification, the term subspecies refers to one of two or more populations of a species living in different subdivisions of the species' range and varying from one another by morphological characteristics.
A single 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, ssp. in zoology. The plural is the same as the singular: subspecies.
In zoology, under the International Code of Zoological Nomenclature, the subspecies is the only taxonomic rank below that of species that can receive a name. In botany and mycology, under the International Code of Nomenclature for algae, fungi, and plants, other infraspecific ranks, such as variety, may be named. In bacteriology and virology, under standard bacterial nomenclature and virus nomenclature, there are recommendations but not strict requirements for recognizing other important infraspecific ranks.
A taxonomist decides whether to recognize a subspecies or not. A common criterion for recognizing two distinct populations as subspecies rather than full species is the ability of them to interbreed without a fitness penalty. In the wild, subspecies do not interbreed due to geographic isolation or sexual selection. The differences between subspecies are usually less distinct than the differences between species.Syntype
In biological nomenclature, a syntype is any one of two or more biological types that is listed in a description of a taxon where no holotype was designated. Precise definitions of this and related terms for types have been established as part of the International Code of Zoological Nomenclature and the International Code of Nomenclature for algae, fungi, and plants.Tautonym
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.
Tautonymy (i.e., the usage of tautonymous names) is permissible in zoological nomenclature (see List of tautonyms for examples). In past editions of the zoological Code, the term tautonym was used, but it has now been replaced by the more inclusive "tautonymous names"; these include trinomial names such as Gorilla gorilla gorilla, and Bison bison bison.
For animals, a tautonym implicitly indicates that the species is the type of its genus. This can also be indicated by a species name with the specific epithet typus or typicus, although more commonly the type species is designated another way.Taxonomic rank
In biological classification, taxonomic rank is the relative level of a group of organisms (a taxon) in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, order, class, phylum, kingdom, domain, etc.
A given rank subsumes under it less general categories, that is, more specific descriptions of life forms. Above it, each rank is classified within more general categories of organisms and groups of organisms related to each other through inheritance of traits or features from common ancestors. The rank of any species and the description of its genus is basic; which means that to identify a particular organism, it is usually not necessary to specify ranks other than these first two.Consider a particular species, the red fox, Vulpes vulpes: the next rank above, the genus Vulpes, comprises all the "true" foxes. Their closest relatives are in the immediately higher rank, the family Canidae, which includes dogs, wolves, jackals, and all foxes; the next higher rank, the order Carnivora, includes caniforms (bears, seals, weasels, skunks, raccoons and all those mentioned above), and feliforms (cats, civets, hyenas, mongooses). Carnivorans are one group of the hairy, warm-blooded, nursing members of the class Mammalia, which are classified among animals with backbones in the phylum Chordata, and with them among all animals in the kingdom Animalia. Finally, at the highest rank all of these are grouped together with all other organisms possessing cell nuclei in the domain Eukarya.
The International Code of Zoological Nomenclature defines rank as: "The level, for nomenclatural purposes, of a taxon in a taxonomic hierarchy (e.g. all families are for nomenclatural purposes at the same rank, which lies between superfamily and subfamily)."Type species
In zoological nomenclature, a type species (species typica) 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.
In botanical nomenclature, these terms have no formal standing under the code of nomenclature, but are sometimes borrowed from zoological nomenclature. In botany, the type of a genus name is a specimen (or, rarely, an illustration) which is also the type of a species name. The species name that has that type can also be referred to as the type of the genus name. Names of genus and family ranks, the various subdivisions of those ranks, and some higher-rank names based on genus names, have such types.In bacteriology, a type species is assigned for each genus.Every named genus or subgenus in zoology, whether or not currently recognized as valid, is theoretically associated with a type species. In practice, however, there is a backlog of untypified names defined in older publications when it was not required to specify a type.Unavailable name
In zoological nomenclature, an unavailable name is a name that does not conform to the rules of the International Code of Zoological Nomenclature and that therefore is not available for use as a valid name for a taxon. Such a name does not fulfil the requirements in Articles 10 through 20 of the Code, or is excluded under Article 1.3.
Unavailable names include names that have not been validly published, such as "Oryzomys hypenemus", names without an accompanying description (nomina nuda), such as the subgeneric name Micronectomys proposed for the Nicaraguan rice rat, names proposed with a rank below that of subspecies (infrasubspecific names), such as Sorex isodon princeps montanus for a form of the taiga shrew, and various other categories.Water treader
Water treaders, the superfamily Mesovelioidea, are insects in the order Hemiptera, the true bugs. They are semiaquatic insects that live in moist and wet habitat and on wet plant matter in several types of aquatic habitat.These insects are no more than 3.5 mm long. They have elongated heads, long antennae, and large eyes, with the exception of Cryptovelia species, which have vestigial eyes. Females are larger than the males of their species and have well-developed ovipositors.The type genus, Mesovelia, contains about 27 species, many of which are common and widespread. The other genera are small or even monotypic, and are less common.
One species is known for its unique specific name, Cavaticovelia aaa, sometimes called the aaa water treader. It is a legitimate binomial name following the International Code of Zoological Nomenclature, featuring aaa, the Hawaiian word for "lava tube".According to some treatments, two families are in the Mesovelioidea. In others, the family Madeoveliidae is treated as a subfamily of the Mesoveliidae.The two families, separated, with included genera are:
Madeovelia Poisson, 1959
Mesoveloidea Hungerford, 1929
Mesoveliidae – water treaders, pondweed bugsAustrovelia
Cryptovelia Andersen & Polhemus, 1980
Darwinivelia Andersen & Polhemus, 1980
Mesovelia Mulsant and Rey, 1852
Mniovelia Andersen & Polhemus, 1980
Phrynovelia Horváth, 1915
Seychellovelia Andersen & Polhemus, 2003
Speovelia Esaki, 1929
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