Nomen dubium

Definition

In zoological nomenclature, a scientific name whose application is uncertain because the original type specimen is lost, damaged, or lacks diagnostic features, or because the original description is insufficient to distinguish the taxon from related species. A nomen dubium cannot be used as a valid name for a species and typically cannot serve as the type for a genus; it may be suppressed or replaced by a neotype designation if the original material is inadequate.

Etymology

Latin: 'doubtful name'

Example

The spider name Lycosa tarantula (Linnaeus, 1758) became a nomen dubium because the original description lacked sufficient detail to distinguish it from numerous similar wolf spiders; the name was later stabilized by designation of a neotype.

Synonyms

• dubious name
• name of doubtful application

Related Terms

• Nomen conservandum
• Nomen oblitum
• neotype
• Holotype
• lectotype
• Type specimen
• principle of priority
• taxonomic stability

Usage Notes

Contrast with nomen conservandum (a name protected by the International Commission on Zoological Nomenclature despite priority issues) and nomen oblitum (a long-unused senior synonym). A nomen dubium is not automatically invalid but is functionally unusable until clarified; the term applies only when the doubt concerns identity of the type, not when the taxon is simply poorly known or rarely collected. In entomology, many nineteenth-century species descriptions based on single damaged specimens become nomina dubia. Resolution typically requires rediscovery of type material, designation of a neotype with Commission approval, or formal suppression.