Judicial Opinions 133 and 134

Opinion 133 addresses the unusual situation of two genus names that are homonyms and are also considered heterotypic synonyms. Furthermore, it clarifies the meaning of the term ‘homonym’ in the International Code of Nomenclature of Prokaryotes, as well as the implications of the absence of the term ‘isonym’ from that code. Isonyms are homotypic synonyms with the same spelling and as such are adequately regulated by the code. The Judicial Commission agrees that the names Methylacidiphilum caldifontis Awala et al . 2023, Methylacidiphilum Awala et al . 2023, Methylacidiphilaceae Awala et al . 2023 and Methylacidiphilales Awala et al . 2023 are illegitimate. The possible actions to resolve this illegitimacy are outlined. The request to conserve Methylacidiphilum Awala et al . 2023 over Methylacidiphilum Ratnadevi et al . 2023 is not granted. However, Methylacidiphilaceae Awala et al . 2023 and Methylacidiphilales Awala et al . 2023 are conserved with Methylacidiphilum Ratnadevi et al . 2023 as the type genus, thereby rendering them legitimate. Opinion 134 addresses two distinct enquiries arising from the same Request for an Opinion. The Judicial Commission confirms that the priority between Yokenella regensburgei Kosako et al . 1985 and its heterotypic synonym Koserella trabulsii Hickman-Brenner et al . 1985 may at present be unresolved. Considering previous statements by the Judicial Commission, the differences in the amount of usage between the two names and their medical relevance, the request is granted. The name Yokenella Kosako et al . 1985 is conserved over Koserella Hickman-Brenner et al . 1985, as is the epithet in Yokenella regensburgei Kosako et al . 1985 over the epithet in Koserella trabulsii Hickman-Brenner et al . 1985. The Judicial Commission also confirms that the epithet in Proteus inconstans (Ornstein 1920) Shaw and Clarke 1955 (Approved Lists 1980) has priority over the one in its homotypic synonym Providencia alcalifaciens (de Salles Gomes 1944) Ewing 1962 (Approved Lists 1980). However, it is doubtful whether this renders Providencia Ewing 1962 (Approved Lists 1980) illegitimate. There are other reasons to conserve the epithet in Providencia alcalifaciens (de Salles Gomes 1944) Ewing 1962 (Approved Lists 1980) over that in Proteus inconstans (Ornstein 1920) Shaw and Clarke 1955 (Approved Lists 1980), and this request is also granted.