 In each case, the earliest published name is called the senior synonym, while the later name is the junior synonym.In the case where two names for the same taxon have been published simultaneously, the valid name is selected accorded to the principle of the first reviser such that, for example, of the names "Strix scandiaca" and "Strix noctua" (Aves), both published by Linnaeus in the same work at the same date for the taxon now determined to be the snowy owl, the epithet "scandiaca" has been selected as the valid name, with "noctua" becoming the junior synonym (this species is currently classified in the genus "Bubo", as "Bubo scandiacus").One basic principle of zoological nomenclature is that the earliest correctly published (and thus available) name, the senior synonym, by default takes precedence in naming rights and therefore, unless other restrictions interfere, must be used for the taxon.