,
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. 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 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 the species
Homo neanderthalensis was the specimen "Neanderthal-1" discovered by
Johann Karl Fuhlrott in 1856 at Feldhofer in the Neander Valley in Germany, consisting of a
skullcap, thigh bones, part of a pelvis, some ribs, and some arm and shoulder bones. There may be more than one type specimen, but there is (at least in modern times) only one holotype. • A
type species is the
nominal species that is the name-bearing type of a nominal
genus or
subgenus. • A
type genus is the
nominal genus that is the name-bearing type of a nominal family-group taxon. • The
type series are all those specimens included by the author in a taxon's formal description, unless the author explicitly or implicitly excludes them as part of the series.
Use of type specimens '' 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 '''''' (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 defined:
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.
Paratype When the original description designated a holotype, there may be additional specimens that the author designates as additional representatives of the same species, termed paratypes. These are not
name-bearing types.
Allotype 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. He published the first book considered to be part of zoological nomenclature, the
10th edition of Systema Naturae, which included the first description of
Homo sapiens and determined all valid syntypes for the species. 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.
Hapantotype A special case in
protists 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 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.
Iconotype An illustration on which a new species or subspecies was based. For instance, the Burmese python,
Python bivittatus, is one of many species that are based on illustrations by
Albertus Seba (1734).
Ergatotype An ergatotype is a specimen selected to represent a worker member in
hymenopterans which have polymorphic castes.
Hypotype A hypotype is a specimen whose details have previously been published that is used in a supplementary figure or description of the species.
Kleptotype The term "
kleptotype" informally refers to a type specimen or a part of it that has been stolen, or improperly relocated.
Alternatives to preserved specimens 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 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 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.
Formalisation of the type system The various types listed above are necessary because many species were described one or two centuries ago, when 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 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 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 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.
Type species ,
Bufo bufo described by
Linnaeus, is the type species for the genus
Bufo 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 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 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==