Principle of homonymy

Principle of Homonymy
Field	Zoological nomenclature
Governing code	International Code of Zoological Nomenclature
Purpose	Ensures that each taxon has a unique scientific name
Defined in	Article 52, ICZN
Related principles	Principle of Priority, Principle of Coordination, Principle of Typification
Applies to	Animal taxa

In zoology, the principle of homonymy is one of the guiding principles of the International Code of Zoological Nomenclature. It states that any one name, in one particular spelling, may be used only once (within its group).

Typically, once a name is made available, any later name with the same spelling (a homonym) is prohibited and must be replaced. The principles of priority and the first reviser apply here. For family-group names the termination (which is rank-bound) is not taken into account, nor are grammatically acceptable alternative spellings or terminations of species-group names (e.g., caeruleus and coeruleus are homonyms, as are smithi and smithii).

In 1777 Johann Reinhold Forster published the name Echidna for a genus of moray eels. This meant that when Georges Cuvier proposed to use this name Echidna in 1797 for the spiny anteater he created a junior homonym. Later, in 1811, Johann Karl Wilhelm Illiger published the name Tachyglossus, as a replacement name, or nomen novum, and this is considered to be the valid name for the spiny anteater.