Nomen oblitum

Definition

In zoological nomenclature under the International Code of Zoological Nomenclature (ICZN), a scientific name that has been formally suppressed as 'forgotten' because it has not been used as a valid name for a taxon after 1899 (or, for names published before 1900, has been treated as a junior synonym for at least fifty years), and which is replaced by a 'protected' nomen protectum to preserve nomenclatural stability. A nomen oblitum lacks priority and cannot displace the younger but widely used protected name, even if the obliterated name would otherwise have priority by date of publication.

Etymology

Latin, 'forgotten name'

Example

The generic name *Pseudomyrma* Lund, 1831 was suppressed as a nomen oblitum in favor of *Pseudomyrmex* Lund, 1830 for New World twig ants, preserving a century of ecological and taxonomic literature that used the younger but universally adopted *Pseudomyrmex*.

Synonyms

• forgotten name

Related Terms

• nomen protectum
• Nomen dubium
• Nomen conservandum
• principle of priority
• suppressed name
• ICZN

Usage Notes

The nomen oblitum mechanism (Article 23.9 of the ICZN) applies only when the senior synonym has been unused for 50+ years and the junior synonym has been used in at least 25 works by 10+ authors in the preceding 50 years. This is distinct from a nomen dubium (doubtful application) or nomen nudum (unavailable name). The reversal of precedence requires formal action by the ICZN Commission; a name does not become a nomen oblitum automatically through disuse alone. The plural form 'nomina oblita' is standard in taxonomic literature.