A genus (plural: genera, from Latin genus "descent, family, type, gender") is a low-level taxonomic rank used in the classification of living and fossil organisms. Taxonomic rank ( rank, category, taxonomic category is an abstract term used in the Scientific classification, or Taxonomy, of organisms
Like almost all other taxonomic units, genera may sometimes be divided into subgenera, singular: subgenus. In Biology, a subgenus is a Taxonomic rank directly below Genus. The largest main taxonomic unit below the genus is the species.
How to more precisely define a genus is a matter of continuing debate, as outlined a few paragraphs below this.
Generic name is a part of the scientific name for an organism. It is a name which reflects the classification of the organism by grouping it with other closely similar organisms. The generic name is always Latin, and is the first of the two names in the scientific name (the second is the species). The first letter of the generic name is always capitalized, and the first letter of the specific name is never capitalized. For example, the scientific name for the wolf is Canis lupis. Canis, meaning dog, is the generic name, because the wolf is a canine.
Because of the rules of scientific naming, or "nomenclature", each genus must have a designated type species (see Type (zoology)) which defines the genus; the generic name is permanently associated with the type specimen of its type species. In Taxonomy, a type species is the species that originally defined a genus. In biology a type is that which fixes a name to a Taxon. Depending on the nomenclature code which is applied to the organism in question a type may be a specimen In biology a type is that which fixes a name to a Taxon. Depending on the nomenclature code which is applied to the organism in question a type may be a specimen Should this specimen turn out to be assignable to another genus, the genus name linked to it becomes a junior synonym, and the remaining taxa in the now-invalid genus need to be reassessed. In Scientific nomenclature, synonyms are different Scientific names used for a single Taxon. A taxon (plural taxa) or taxonomic unit, is a name designating an organism or a group of Organisms In Biological nomenclature according to See scientific classification and Nomenclature Codes for more details of this system. The Nomenclature Codes (or the " Codes of nomenclature") are the rulebooks that govern biological nomenclature Also see type genus. In biology the phrase type genus is used differently depending on the nomenclatural ''Code'' that applies In zoological nomenclature, a type
The rules-of-thumb for delimiting a genus are outlined e. g. in Gill et al. (2005). According to these, a genus should fulfill 3 criteria to be descriptively useful:
Neither the ICZN nor the ICBN require such criteria for establishment of a genus, and this is because they are concerned with the rules of nomenclature rather than the rules of taxonomy. "ICZN" redirects here It is also sometimes used for the International Code of Zoological Nomenclature in error The International Code of Botanical Nomenclature ( ICBN) is the set of rules and recommendations dealing with the formal Botanical names that are given to The ICZN and ICBN rule books cover the formalities of what makes a description valid.
The three criteria given above are almost always fulfillable for a given clade. However, an example of a situation where at least one criterion is crassly violated no matter what the generic arrangement is the case of the dabbling ducks in the genus Anas. The Anatinae is a Subfamily of the family Anatidae ( Swans geese and Ducks. Anas is a Genus of Dabbling ducks It includes Mallards Wigeons Teals Pintails and Shovelers in This group is is paraphyletic in regard to the extremely distinct fossil species, moa-nalo. In Phylogenetics, a group of organisms is said to be paraphyletic if the group contains its most recent common ancestor but does not contain all Moa-nalo are a group of Extinct aberrant Goose -like Ducks that formerly lived on the Hawaiian Islands in the Pacific. Considering these to be distinct genera (as is usually done) violates criterion 1, including them all in the genus Anas violates criterion 2 and 3, and splitting up the genus Anas so that the mallard and the American black duck are in distinct genera violates criterion 3. The Mallard ( Anas platyrhynchos) probably the best-known and most recognizable of all ducks is a Dabbling duck which breeds throughout the Temperate The American Black Duck ( Anas rubripes) is a large Dabbling duck.
A genus in one kingdom is allowed to bear a name that is in use as a genus name or other taxon name in another kingdom. In biological Taxonomy, a kingdom or regnum is a Taxonomic rank in either (historically the highest rank or (in the new three-domain system Although this is discouraged by both the International Code of Zoological Nomenclature and the International Code of Botanical Nomenclature there are some five thousand such names that are in use in more than one kingdom. The International Code of Zoological Nomenclature is a set of rules in Zoology that have one fundamental aim to provide the maximum universality and continuity in the naming The International Code of Botanical Nomenclature ( ICBN) is the set of rules and recommendations dealing with the formal Botanical names that are given to For instance, Anura is the name of the order of frogs but also is the name of a genus of plants (although not current: it is a synonym); and Aotus is the genus of golden peas and night monkeys; Oenanthe is the genus of wheatears and water dropworts, and Prunella is the genus of accentors and self-heal. This article is about the block cipher algorithm For the ultrafast laser pulse measurement technique see Frequency-resolved optical gating. This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used This article is about the block cipher algorithm For the ultrafast laser pulse measurement technique see Frequency-resolved optical gating. In Scientific nomenclature, synonyms are different Scientific names used for a single Taxon. The Night monkeys, also known as the Owl monkeys or Douroucoulis, are the members of the Genus Aotus of New World monkeys The wheatears are birds of the Genus Oenanthe. They were formerly considered to be members of the thrush family Turdidae but are now more See Oenanthe for the Bird genus of this name The Oenanthe or water dropworts is a genus of plants from the family Apiaceae The accentors are in the only Bird family the Prunellidae, which is completely endemic to the Palearctic. Prunella is a genus of seven species of Herbaceous Plants in the family Lamiaceae, also known as self-heals or "allheal"
Within the same kingdom one generic name can apply to only one genus. This explains why the platypus genus is named Ornithorhynchus — George Shaw named it Platypus in 1799, but the name Platypus had already been given to the pinhole borer beetle by Johann Friedrich Wilhelm Herbst in 1793. The Platypus ( Ornithorhynchus anatinus) is a semi- aquatic Mammal endemic to eastern Australia, including Tasmania. George Shaw ( December 10, 1751 - July 22, 1813) was an English Botanist and Zoologist. Beetles are the group of Insects with the largest number of known Species. Johann Friedrich Wilhelm Herbst ( 1 November 1743 – 5 November 1807) was a German naturalist and Entomologist Names with the same form but applying to different taxa are called homonyms. Since beetles and platypuses are both members of the kingdom Animalia, the name Platypus could not be used for both. Johann Friedrich Blumenbach published the replacement name Ornithorhynchus in 1800.