Type (biology)

In biology, a type is a special example of a living thing that scientists use to describe a group of organisms. This example, called a specimen, helps scientists understand the key features of that group. When scientists give a name to a new plant, animal, or any other living thing, they often choose one specimen to be the type. This type specimen is kept in a museum or research collection so that other scientists can study it.

A group of organisms with a special name is called a taxon. For example, a species is a type of taxon. When scientists describe a new species, they write a detailed description and usually choose a type specimen. This specimen serves as the central example for that species. By looking at the type, scientists can compare it with other examples to see if they belong to the same group.

Types are important because they help keep scientific names clear and consistent. They make sure that everyone is talking about the same group of organisms when they use a particular name. This way, scientists all over the world can share their discoveries and understand each other better.

Type specimen

Main article: type specimen (mineralogy)

In biology, scientists use special examples of plants, animals, or other living things to give names to groups of organisms. These special examples are called type specimens. They help scientists agree on what each name means.

Usually, a type specimen is a real plant or animal kept safe in a museum or a research collection. Sometimes, a picture can also serve as a type. When scientists find a new group of organisms, they pick one specimen to be the type and give it a name. This way, everyone knows exactly which group they are talking about when they use that name. For example, a bird in a museum in London is the type for the species called Circus assimilis, the spotted harrier. This helps scientists study and talk about animals and plants clearly.

Older terminology

In some older books about grouping living things, the word "type" was used in different ways. At first, it had a meaning similar to what we now call a "taxon." But in other books, it was used in a way that is closer to how we think of a group of related plants or animals today. This shows how the way scientists talk about living things has changed over time.

In botany

In botanical nomenclature, a type is the special example used to link a plant name to a real plant. This can be a real plant kept safe in a herbarium, or sometimes just a picture if the real plant was hard to keep.

Types help scientists agree on what a plant name means, even when they disagree about how big the group of plants should be. For example, the name for a common plant like the dandelion can refer to many small kinds or just one big group — but the type example stays the same.

The most common kinds of types include:

• holotype – the main example chosen by the scientist who named the plant
• lectotype – chosen later if the main example was lost
• isotype – a copy of the main example
• syntype – any of several examples used when there was no single main one
• paratype – extra examples used to help describe the plant
• neotype – chosen if no original examples are left
• epitype – extra detail added later to help identify the plant better

In zoology

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."

A type specimen is a 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.

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 be additional specimens that the author designates as additional representatives of the same species, termed paratypes. These are not name-bearing types.

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. 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 types.

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.

Main article: Type species

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.

Main article: 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.