Types and Type Specimens
A type is the physical specimen or other element that permanently anchors a scientific name, fixing what the name refers to regardless of later changes in concept.
Definition
A name-bearing type is the specimen, illustration, or culture to which a scientific name is permanently attached, serving as the objective standard for the application of that name.
Scope
This topic covers the type method and the categories of types, including holotype, paratype, lectotype, neotype, and syntype, the role of name-bearing types in defining the application of a name, and the curation of type material in natural history collections.
Core questions
- What is a type and why is it needed?
- What are the main categories of types?
- How does a type fix the meaning of a name when concepts change?
- How is type material curated and made accessible?
Key theories
- Name-bearing type
- Each available name is tied to a name-bearing type, so that the name's application is determined by reference to a real object rather than by a verbal definition that may shift over time.
- Designation of replacement types
- When an original type is lost or was never designated, the codes allow designation of a lectotype from original material or a neotype to stabilize the name's application.
Clinical relevance
Type specimens are the ultimate reference for confirming the identity of organisms in disputes over pathogens, regulated species, and biological resources, making natural history collections critical infrastructure for verification.
History
The type method emerged in the nineteenth and early twentieth centuries to halt the drift in how names were applied; it is now central to all the codes, with billions of type and reference specimens housed in museums and herbaria worldwide.
Debates
- Whether DNA or images can serve as types
- As collecting becomes constrained, there is debate over allowing photographs or sequence data to serve as types for organisms that cannot be preserved, weighed against the verifiability of physical specimens.
Key figures
- Ernst Mayr
Related topics
Seminal works
- iczn1999
- winston1999
Frequently asked questions
- What is a holotype?
- A holotype is the single specimen designated by the author as the name-bearing type when a species is first described, serving as the definitive reference for that name.
- What happens if a type specimen is destroyed?
- The codes permit designation of a neotype, a replacement name-bearing specimen, to restore an objective standard for the name when the original type is lost.