Type genus

In biological classification, especially zoology, the type genus is the genus which defines a biological family and the root of the family name.

Female mallard nest - natures pics
A female mallard (Anas platyrhynchos) and her clutch of ducklings. Anas is the type genus for the family Anatidae.

Zoological nomenclature

According to the International Code of Zoological Nomenclature, "The name-bearing type of a nominal family-group taxon is a nominal genus called the 'type genus'; the family-group name is based upon that of the type genus."[1]

Any family-group name must have a type genus (and any genus-group name must have a type species, but any species-group name may, but need not, have one or more type specimens). The type genus for a family-group name is also the genus that provided the stem to which was added the ending -idae (for families).

Example: The family name Cricetidae has as its type genus the genus Cricetus Leske, 1779.

Botanical nomenclature

In botanical nomenclature, the phrase "type genus" is used, unofficially, as a term of convenience. In the ICN this phrase has no status. The code uses type specimens for ranks up to family, and types are optional for higher ranks.[2] The Code does not refer to the genus containing that type as a "type genus".

Example: "Poa is the type genus of the family Poaceae and of the order Poales" is another way of saying that the names Poaceae and Poales are based on the generic name Poa.

See also


  1. ^ ICZN Code Art. 63. "Name-bearing types."
  2. ^ McNeill, J.; Barrie, F.R.; Buck, W.R.; Demoulin, V.; Greuter, W.; Hawksworth, D.L.; Herendeen, P.S.; Knapp, S.; Marhold, K.; Prado, J.; Prud'homme Van Reine, W.F.; Smith, G.F.; Wiersema, J.H.; Turland, N.J. (2012). International Code of Nomenclature for algae, fungi, and plants (Melbourne Code) adopted by the Eighteenth International Botanical Congress Melbourne, Australia, July 2011. Regnum Vegetabile 154. A.R.G. Gantner Verlag KG. ISBN 978-3-87429-425-6.

Achatinellidae is a family of tropical air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Achatinelloidea.


Apiaceae or Umbelliferae is a family of mostly aromatic flowering plants named after the type genus Apium and commonly known as the celery, carrot or parsley family, or simply as umbellifers. It is the 16th-largest family of flowering plants, with more than 3,700 species in 434 genera including such well-known and economically important plants such as ajwain, angelica, anise, asafoetida, caraway, carrot, celery, chervil, coriander, cumin, dill, fennel, poison hemlock, lovage, cow parsley, parsley, parsnip and sea holly, as well as silphium, a plant whose identity is unclear and which may be extinct.The family Apiaceae includes a significant number of phototoxic species and a smaller number of poisonous species. Some species in the family Apiaceae are cytotoxic.


According to APG II, the Asclepiadaceae, commonly known as milkweed family, is a former plant family now treated as a subfamily (subfamily Asclepiadoideae) in the Apocynaceae (Bruyns 2000).

They form a group of perennial herbs, twining shrubs, lianas or rarely trees but notably also contain a significant number of leafless stem succulents. The name comes from the type genus Asclepias (milkweeds).

There are 348 genera, with about 2,900 species. They are mainly located in the tropics to subtropics, especially in Africa and South America.

The florally advanced tribe Stapeliae within this family contains the relatively familiar stem succulent genera such as Huernia, Stapelia and Hoodia. They are remarkable for the complex mechanisms they have developed for pollination, which independently parallel the unrelated Orchidaceae, especially in the grouping of their pollen into pollinia. The fragrance from the flowers, often called "carrion", attracts flies. The flies pollinate the flowers.

Many new hybrids have been formed due to the unique fertilization method of the flowers.


Asteraceae or Compositae (commonly referred to as the aster, daisy, composite, or sunflower family) is a very large and widespread family of flowering plants (Angiospermae).The family currently has 32,913 accepted species names, in 1,911 genera (list) and 13 subfamilies. In terms of numbers of species, the Asteraceae are rivaled only by the Orchidaceae. (Which of the two families is actually larger is unclear, owing to uncertainty about exactly how many species exist in each family.). Nearly all members bear their flowers in dense heads (capitula or pseudanthia) surrounded by involucral bracts. When viewed from a distance, each capitulum may have the appearance of being a single flower. Enlarged outer (peripheral) flowers in the capitula may resemble petals, and the involucral bracts may look like a calyx. The name Asteraceae comes from the type genus Aster, from the Ancient Greek ἀστήρ, meaning star, and refers to the star-like form of the inflorescence. Compositae is an older (but still valid) name that refers to the "composite" nature of the capitula, which consist of (few to) many individual flowers.

Most members of Asteraceae are annual or perennial herbs, but a significant number are also shrubs, vines, or trees. The family has a worldwide distribution, from the polar regions to the tropics, colonizing a wide variety of habitats. It is most common in the arid and semiarid regions of subtropical and lower temperate latitudes, . The Asteraceae may represent as much as 10% of autochthonous flora in many regions of the world.

Asteraceae is an economically important family, providing products such as cooking oils, lettuce, sunflower seeds, artichokes, sweetening agents, coffee substitutes and herbal teas. Several genera are of horticultural importance, including pot marigold (Calendula officinalis), Echinacea (coneflowers), various daisies, fleabane, chrysanthemums, dahlias, zinnias, and heleniums. Asteraceae are important in herbal medicine, including Grindelia, yarrow, and many others. A number of species are considered invasive, including, most notably in North America, dandelion, which was originally introduced by European settlers who used the young leaves as a salad green.The study of this family is known as synantherology.


The Brucellaceae are a family of the Gram-negative Rhizobiales. They are named after Sir David Bruce, a Scottish microbiologist. They are aerobic chemoorganotrophes. The family comprises pathogen and soil bacteriaSee Brucella, the type genus, and brucellosis, a disease caused by Brucella.


Charopidae is a taxonomic family of small air-breathing land snails (and semi-slugs such as Otoconcha dimidiata), terrestrial pulmonate gastropod mollusks in the superfamily Punctoidea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).


Endomychidae, or handsome fungus beetles, is a family of beetles with representatives found in all ecozones. There are around 120 genera and 1300 species. The family was established based on the type genus Endomychus, a genus erected in 1795 by Panzer which was applied to a species that Linnaeus called as Chrysomela coccinea. As the common name suggests, Endomychidae feed on fungi. Crowson, in his influential treatment of the beetles, placed the family within the Cucujoidea. They have a tarsal formal of 4-4-4 or 3-3-3 and the wings lack a closed radial cell. The second antennal segment has a sensory appendage that is as long as the third antennal segment. The family has also been grouped with the Coccinellidae in a group called the Trimera for having pseudotrimerous tarsi. A 2015 molecular phylogeny study found that the Cucujoidea were found to be non-monophyletic and the Endomychidae was refined with the removal of the Anamorphinae from within the family and elevated to the status of a full family. Mycetaeinae and Eupsilobiinae were also found not to belong within the clades of the core Endomychidae.The subfamilies that are included:


Endomychinae (including Stenotarsinae)








"Enterobacteriales" with its type genus Escherichia is an order of gram-negative bacteria that was proposed in 2005. However, the name "Enterobacteriales" was not validated, thus it lacks standing in nomenclature. For this reason the name should be written in parentheses as "Enterobacteriales." The order "Enterobacteriales" includes only the family Enterobacteriaceae.Efforts are underway to validate the name Enterobacteriales so it will have standing in nomenclature.

For a list of genera see Enterobacteriaceae.


The Fasciolariidae, common name the "tulip snails and spindle snails", are a family of small to large sea snails, marine gastropod mollusks in the superfamily Buccinoidea.

The family Fasciolariidae probably appeared about 110 million years ago during the Cretaceous


The Garniidae are a family of parasites in the phylum Apicomplexia. Like many species in the Apicomplexia, all species in this family have two hosts in their lifecycles – one in a vertebrate and one in an invertebrate. The vertebrate hosts are reptiles or birds, but the invertebrate hosts are not known for many of the species.

Species in this family are parasites of erythrocytes and diverse white blood cells. They do not produce pigment, but do have an asexual cycle in the blood.

The type genus is Garnia.


The haplochromine cichlids are a tribe of cichlids in subfamily Pseudocrenilabrinae called Haplochromini. This group includes the type genus (Haplochromis) plus a number of closely related genera such as Aulonocara, Astatotilapia, and Chilotilapia. They are endemic to eastern, southern and northern Africa, except for Astatotilapia flaviijosephi in the Middle East. A common name in a scientific context is East African cichlids – while they are not restricted to that region, they are the dominant Cichlidae there. This tribe was extensively studied by Ethelwynn Trewavas, who made major reviews in 1935 and 1989, at the beginning and at the end of her career in ichthyology. Even today, numerous new species are being described each year.

The haplochromines were in older times treated as subfamily Haplochrominae, However, the great African radiation of pseudocrenilabrine cichlids is certainly not monophyletic without them, and thus they are today ranked as a tribe therein. They do include, however, the type genus of the subfamily, Pseudocrenilabrus. Since taxonomic tribes are treated like genera for purposes of biological nomenclature according to the ICZN, the Haplochromis is the type genus of this tribe, and not the (later-described) Pseudocrenilabrus, even though the tribe name Pseudocrenilabrini was proposed earlier.

In the African Great Lakes, there has been an amazing adaptive radiation of Haplochromini. Many have interesting behavior (e.g. mouthbrooding in Astatotilapia burtoni or the "sleeper" ambushes of Nimbochromis), and brilliant colours are also widespread. Males and females are often strikingly sexually dichromatic. In the aquarium hobby, these fishes are popular for these reasons. They are often aggressive and demand rather unusual water parameters, making them generally unsuited for beginners or community tanks. There are some informal names used among aquarists for Haplochromini. Generally, any and all (as well as some similar-looking Pseudocrenilabrinae) may be referred to haplos, haps or happies. More specific terms are mbuna ("rock-dwelling browser") and utaka ("free-roaming hunter"), which are Bantu terms for these two ecological groups.

Haplochromines inhabit both rivers and lakes, but it is the lake species that have been most closely studied because of the species flocks known from some of the larger lakes, such as Lake Malawi. In the aquarium hobby, the "happies" are conveniently divided into four groups:

Riverine species and those endemic to the northern Great Lakes such as Lake Kivu and Lake Victoria

Mbuna, endemic to Lake Malawi

Utaka and other non-mbuna species endemic to Lake Malawi

Species endemic to Lake TanganyikaLake Victoria's trophic web was thoroughly upset in the second half of the 20th century, after Nile Perch (Lates niloticus) were introduced to the lake. Among the haplochromines found there, there have been many extinctions, and a number of other species only survive in aquaria. One monotypic genus, Hoplotilapia, is believed to be entirely extinct at least in the wild.


Jeholosaurids were herbivorous neornithischian dinosaurs from the Cretaceous Period (Aptian - Santonian, with a possible Campanian record) of Asia. The family was first proposed by Han et al. in 2012. The jeholosaurids were defined as those ornithischians more closely related to Jeholosaurus shangyuanensis than to Hypsilophodon foxii, Iguanodon bernissartensis, Protoceratops andrewsi, Pachycephalosaurus wyomingensis, or Thescelosaurus neglectus. The Jeholosauridae includes the type genus Jeholosaurus and Yueosaurus.


The Nitrosomonadales are an order of the class Betaproteobacteria in the phylum "Proteobacteria". Like all members of their class, they are Gram-negative.

The order is divided into six families:Nitrosomonadaceae (type family) comprises the genera Nitrosomonas (type genus), Nitrosolobus and Nitrosospira. Methylophilaceae comprises the genera Methylophilus (type genus), Methylobacillus and Methylovorus. Spirillaceae comprises the genus Spirillum (type genus) Thiobacillaceae comprises the genera Thiobacillus (type genus), Annwoodia, Sulfuritortus. Gallionellaceae comprises the genera Gallionella (type genus), Ferriphaselus, Sulfuriferula, Sulfurirhabdus and Sulfuricella. Sterolibacteraceae comprises the genera Sterolibacterium, Sulfurisoma, Denitratisoma, Sulfuritalea, Georgfuchsia, Sulfurisoma and Methyloversatilis.Members of the genus Nitrosomonas oxidize ammonium ions into nitrite, - a process called nitrification - and are important in the nitrogen cycle. Other autotrophic genera such as Thiobacillus and Annwoodia oxidize reduced inorganic sulfur ions such as thiosulfate and sulfide into sulfate and have key roles in the sulfur cycle. Methylotrophs such as Methylophilus oxidize compounds such as methanol into carbon dioxide and are key to the carbon cycle. Gallionella and Ferriphaselus oxidise ferric iron (Fe3+) ions into ferric hydroxide (Fe(OH)3) during autotrophic growth, and thus have roles in the carbon cycle and the iron cycle. As such, the Nitrosomonadales are critical to biogeochemical cycling of the elements and many species have key roles in principal biochemical processes.


The Plasmodiidae are a family of apicomplexan parasites, including the type genus Plasmodium, which is responsible for malaria. This family was erected in 1903 by Mesnil and is one of the four families in the order Haemospororida.


The Rhodocyclales are an order of the class Betaproteobacteria in the phylum "Proteobacteria". Following a major reclassification of the class in 2017, the previously monofamilial order was split into three families:

Rhodocyclaceae (type family) contains the genera Rhodocyclus (type genus), Azospira and Propionivibrio. Cells are curved rods, rings or spirillae. Dominant respiratory quinones are menaquinone-8, ubiquinone-8 and rhodoquinone-8. G+C fractions are 61.6 - 65.3 mol%.

Azonexaceae contains the genera Azonexus (type genus), Dechloromonas, Ferribacterium and Quatrionicoccus. Cells are curved rods or cocci. Dominant respiratory quinone is ubiquinone-8. G+C fractions are 63.5 - 67.0 mol%.

Zoogloeaceae contains the genera Zoogloea (type genus), Thauera, Uliginosibacterium and Azoarcus. Cells are rod shaped. Dominant respiratory quinones are ubiquinone-8 and rhodoquinone-8. G+C fractions are 59.3 - 69.0 mol%.The genus Azovibrio also falls within the order but is incertae sedis, falling between the Zoogloeaeceae and the Azonexaceae.


The Santalales are an order of flowering plants with a cosmopolitan distribution, but heavily concentrated in tropical and subtropical regions. It derives its name from its type genus Santalum (sandalwood). Mistletoe is the common name for a number of parasitic plants within the order.

Type (biology)

In biology, a type is a particular specimen (or in some cases a group of specimens) 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 (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, 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.

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.


The Tyranni (suboscines) are a clade of passerine birds that includes more than 1,000 species, the large majority of which are South American. It is named after the type genus Tyrannus.

These have a different anatomy of the syrinx musculature than the oscines (songbirds of the larger suborder Passeri), hence its common name of suboscines. The available morphological, DNA sequence, and biogeographical data, as well as the (scant) fossil record, agree that these two major passerine suborders are evolutionarily distinct clades.


This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.