Diagram 27: Nomenclatural types (Entities)
Storage and management of nomenclatural type specimens is one of the most important responsibilities of natural history collections. The entity Nomenclatural Type is used to record the additional information necessary for type specimens. Moreover, types present in other collections may be included, and photos etc. representing these in the present collection may be registered. The structure also accommodates types for which no specimen exist (illustrations).
Diagram 28: Datastructure of nomenclatural types
All attributes listed as the result of discussions in the TDWG Type Databases Working Group (Farr, unpublished) were accommodated in the model (as attributes or links to other entities) and several were added. Type data include the basionym (Scientific Name) defined by the type and the nomenclatural type status, which defines the kind of type entered (e.g. holotype, isolectotype, etc., see Croft 1992). Normally, a type specimen is indicated, consisting of one or several Units. This link provides all type-data related to the gathering, the storage location (including stored under name), accession number, material category (e.g. illustration), and current determination. The protologue reference identifies the location of the protologue text, or, if in the publication only an illustration exists, of the illustration. The illustration reference identifies an illustration serving as type material. A lecto- or neotypification reference is treated like a protologue. The type's data may have been recorded from literature or from a label, in which case the data source should be indicated. A flag indicating that the type has been checked against the protologue has been included following Farr's recommendation, although objections as to the utility of such a comparison exist. A verification note attribute accommodates further details of the verification. An additional link to a unit references copies of protologue or published illustrations, photographs of type material etc. stored as units in a collection.