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.
1 Type specimen 2 Older terminology 3 In botany 4 In zoology
4.1 Definitions 4.2 Use of type specimens
4.2.1 Holotype 4.2.2 Paratype 4.2.3 Allotype 4.2.4 Neotype 4.2.5 Syntype 4.2.6 Lectotype 4.2.7 Paralectotype 4.2.8 Hapantotype 4.2.9 Ergatotype 4.2.10 Alternatives to preserved specimens 4.2.11 Formalisation of the type system
4.3 Type species 4.4 Type genus
5 See also 6 References 7 External links
According to a precise set of rules laid down in the International
Code of Zoological Nomenclature (ICZN) and 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 a type. Describing species and
appointing type specimens is part of scientific nomenclature and alpha
When identifying material, a scientist attempts to apply a taxon name
to a specimen or group of specimens based on his or her understanding
of the relevant taxa, based on (at least) having read the type
description(s), preferably based on an examination of all the type
material of all of 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.
This process is crucial to the science of biological taxonomy.
People's ideas of how living things should be grouped change and shift
over time. How do we know that what we call "Canis lupus" is the same
thing, or approximately the same thing, as what they will be calling
"Canis lupus" in 200 years' time? It is possible to check this because
there is a particular wolf specimen preserved in Sweden and
everyone who uses that name – no matter what else they may mean by
it – will include that particular specimen.
Depending on 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 18126.96.36.199. This 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.
Note that at least for type specimens there is no requirement for a
"typical" individual to be used.
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 the section ... After studying the diverse forms, I came to consider them as belonging to the one and the same specific type.
In botany In botanical nomenclature, a type (typus, nomenclatural type), "is that element to which the name of a taxon is permanently attached." (article 7.1) 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 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 detailed drawing, painting, etc., depicting the plant, from the early days of plant taxonomy. A dried plant was difficult to transport and hard to keep safe for the future; many specimens from the early days of botany have since been lost or damaged. Highly skilled botanical artists were sometimes employed by a botanist to make a faithful and detailed illustration. Some such illustrations have become the best record and have been chosen to serve as the type of a taxon. A detailed picture of something that can be seen only through a microscope. A tiny "plant" on a microscope slide makes for a poor type: the microscope slide may be lost or damaged, or it may be very difficult to find the "plant" in question among whatever else is on the microscope slide. An illustration makes for a much more reliable type (Art 37.5 of the Vienna Code, 2006).
Note that 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 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 of what the name actually applies to varies greatly. Setting the circumscription of a taxon is done by a taxonomist in a publication. Miscellaneous notes:
Only a species or an infraspecific taxon can have a type of its own. For most new taxa (published on or after 1 January 2007, article 37) at these ranks a type should not be an illustration. A genus has the same type as that of one of its species (article 10). A family has the same type as that of one of its genera (article 10).
The ICN provides a listing of the various kinds of type (article 9), the most important of which is the holotype. These are
holotype lectotype isotype syntype paratype neotype epitype
Note that the word "type" appears in botanical literature as a part of some older terms that have no status under the ICN: for example a clonotype. In zoology
A gossamer-winged butterfly, Jamides elioti: 1) dorsal and 2) ventral aspect of holotype, 3) dorsal and 4) ventral aspect of paratype
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, and 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" "provides the objective standard of reference whereby the application of the name of a nominal taxon can be determined." Definitions
A type specimen is a vernacular term (not a formally defined term)
typically used for an individual or fossil that is any of the various
name-bearing types for a species. For example, the type specimen for
Use of type specimens
Type illustration of Mormopterus acetabulosus
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 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 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
Main article: Holotype
When a single specimen 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.
Main article: Paratype
When the original description designated a holotype, there may still
be additional specimens listed in the type series and those are termed
paratypes. These are not name-bearing types.
An allotype is a specimen of the opposite sex to the holotype,
designated from among paratypes. It 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
the original author never cited a specimen.
Main article: Syntype
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
A lectotype 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 is not uncommon for a
series of syntypes to contain specimens of more than one species.
A notable example is that
The common toad,
Each genus must have a designated type species (the term "genotype" 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 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 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). Type genus Main article: Type genus A type genus is that 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 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. See also
Archetype Glossary of scientific naming Nomen dubium (zoology) Nomen nudum Genetypes - genetic sequence data from type specimens Pathotype – a type of an intrasubspecific taxon of pathogenic bacteria Principle of Typification
^ a b c Hitchcock, A.S. (1921), "The Type Concept in Systematic
Botany", American Journal of Botany, 8 (5): 251–255,
doi:10.2307/2434993, JSTOR 2434993
^ a b Nicholson, Dan H. "Botanical nomenclature, types, & standard
reference works". Smithsonian National
ICZN Code: International Code of Zoological Nomenclature, the official website Fishbase Glossary section. A compendium of terms Zoological Type Nomen