Just Our Types: A Short Guide to Type Specimens

From the Collections posts

A holotype is the single specimen that a researcher designates as the name-bearing representative of a new species. These important specimens ensure that scientists have a single reference point when talking about a particular organism, be it a Corythosaurus casuarius, first described in 1912 from a holotype housed here at the Museum, or the olinguito, described in 2013 (for more about how the Museum’s Mammal # 66753 became its holotype, watch the latest episode of Shelf Life.) 

The skull of the olinguito has a distinct red tag denoting it as a holotype in the Museum's collections.   ©AMNH

The skull of the olinguito has a distinct red tag denoting it as a holotype in the Museum's collections.  

©AMNH


But holotypes are not the only specimens that get special designations. Other type specimens can help provide researchers with a broader range of information, stand in for a missing holotype, or offer insight on the peculiar biology of animals like wasps and ants.

Syntype: Sometimes in the past, prior to making the designation of the holotype a standard practice, multiple specimens were used in describing a new species, with one example singled out. In these cases, each example used in the original description is designated as a syntype.  

Lectotype: Having too many syntypes around can be confusing, though, so often one is selected from the set of syntypes as a representative specimen of the species. These after-the-fact selections are known as lectotypes. Interestingly, the lectotype for Homo sapiens is noted taxonomist Carl Linnaeus. (And in case you were wondering, Linnaeus’s remains do not reside on a museum shelf, but in Sweden’s Uppsala Cathedral.)

In the Museum′s mammalogy collection, holotypes are identified with a red tag like the one above. ©AMNH

In the Museum′s mammalogy collection, holotypes are identified with a red tag like the one above.

©AMNH


Paratype: Even when a holotype is designated, there are often other specimens used in the original description. Those are called paratypes and were often collected at the same time and location as the holotype. Paratypes can become even more important if, for instance, a holotype is ever lost or destroyed. Several paratype specimens are given special note in the Museum’s ornithology type collection because corresponding holotypes, housed in European museums, were destroyed during World War II.

Allotype:When the males and females of a species look very different, researchers sometimes designate an allotype—a specimen of the opposite sex of the holotype . Unlike some other types, this designation is less formal and is not regulated by the International Committee on Zoological Nomenclature, the organization dedicated to keeping names and types in order. 

Ergatotype: Some organisms exhibit great morphological differences within a single species. Ergatotypes are only used in the description of some social insects in the order Hymenoptera, which includes ants, wasps, and bees. An ergatotype represents a typical “worker” insect for their species.