A holotype is a single physical example (or illustration) of an organism, known to have been used when the

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

(or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several examples, but explicitly designated as the holotype. Under the

International Code of Zoological Nomenclature 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 I ...

(ICZN), a holotype is one of several kinds of name-bearing types. In the

International Code of Nomenclature for algae, fungi, and plants The ''International Code of Nomenclature for algae, fungi, and plants'' (ICN) is the set of rules and recommendations dealing with the formal botanical names that are given to plants, fungi and a few other groups of organisms, all those "tra ...

(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 '' Plebejus idas longinus'' is a preserved specimen of that subspecies, held by the

Museum of Comparative Zoology A museum ( ; plural museums or, rarely, musea) is a building or institution that cares for and displays a collection of artifacts and other objects of artistic, cultural, historical, or scientific importance. Many public museums make these ...

at Harvard University. In botany, an isotype is a duplicate of the holotype, 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 is. 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 Even if a better specimen is subsequently found, the holotype is not superseded.

Replacements for holotypes

Under the ICN, an additional and clarifying type could be designated an ''epitype'' under article 9.8, where the original material is demonstrably ambiguous or insufficient. A ''conserved type'' (ICN article 14.3) is sometimes used to correct a problem with a name which has been misapplied; this specimen replaces the original holotype. In the absence of a holotype, another type may be selected, out of a range of different kinds of type, depending on the case, a

lectotype 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 centralizes th ...

or a

neotype 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 centralizes th ...

. For example, in both the ICN and the ICZN a neotype is a type that was later appointed in the absence of the original holotype. Additionally, under the ICZN the commission is empowered to replace a holotype with a neotype, when the holotype turns out to lack important diagnostic features needed to distinguish the species from its close relatives. For example, the crocodile-like

archosaur Archosauria () is a clade of diapsids, with birds and crocodilians as the only living representatives. Archosaurs are broadly classified as reptiles, in the cladistic sense of the term which includes birds. Extinct archosaurs include non-avian ...

ian reptile ''Parasuchus hislopi'' Lydekker, 1885 was described based on a

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ships * R ...

(part of the snout), but this is no longer sufficient to distinguish ''Parasuchus'' from its close relatives. This made the name ''Parasuchus hislopi'' a ''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...

''. Indian-American paleontologist

Sankar Chatterjee Sankar Chatterjee (born May 28, 1943) is a paleontologist, and is the Paul W. Horn Professor of Geosciences at Texas Tech University and Curator of Paleontology at the Museum of Texas Tech University. He earned his Ph. D. from the University o ...

proposed that a new

type specimen 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 centralizes th ...

, a complete skeleton, be designated. The International Commission on Zoological Nomenclature considered the case and agreed to replace the original type specimen with the proposed neotype. The procedures for the designation of a new type specimen when the original is lost come into play for some recent, high-profile

species description A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have b ...

s in which the specimen designated as the holotype was a living individual that was allowed to remain in the wild (e.g. a new species of capuchin monkey, genus ''Cebus'', ''

Marleyimyia xylocopae ''Marleyimyia xylocopae'' is a species of bee fly from South Africa that has a similarity to the patterning of a carpenter bee '' Xylocopa flavicollis'' found in the region. The species is considered to be distinctive and only one of three within ...

'', or the Arunachal macaque ''Macaca munzala''). In such a case, there is no actual type specimen available for study, and the possibility exists that—should there be any perceived ambiguity in the identity of the species—subsequent authors can invoke various clauses in the ICZN Code that allow for the designation of a neotype. Article 75.3.7 of the ICZNInternational Code of Zoological Nomenclature, Art. 75.3.7
/ref> requires that the designation of a neotype must be accompanied by "a statement that the neotype is, or immediately upon publication has become, the property of a recognized scientific or educational institution, cited by name, that maintains a research collection, with proper facilities for preserving name-bearing types, and that makes them accessible for study", but there is no such requirement for a holotype.

References

External links

BOA
Photographs of type specimens of Neotropical Rhopalocera. {{Authority control Zoological nomenclature Botanical nomenclature

Replacements for holotypes

See also

References

External links