Prostoma hokkaidoense, Stiasny-Wijnhoff, 1938

Kajihara, Hiroshi, 2025, A taxonomic revision of the freshwater monostiliferous hoplonemertean genus Prostoma Dugès, 1828 (Nemertea: Eumonostilifera): a radical solution or an over-lumping?, Zootaxa 5646 (4), pp. 451-500 : 473

2. hokkaidoense Stiasny-Wijnhoff, 1938

Source. As “ hokkaidoensis ” ( Stiasny-Wijnhoff 1938: 222) and “ P. hokkaidoensis ” ( Stiasny-Wijnhoff 1938: 224) .

Type locality. Sapporo , Hokkaido, Japan .

Etymology. Adjective, - is, -is, -e; “from Hokkaido ”.

Remarks. Stiasny-Wijnhoff (1938) mistakingly interpreted Ishizuka (1933) as having established a taxon named Prostoma hokkaidoense . In reality, Ishizuka (1933: 218) stated only that “the nemertean of Sapporo [in Hokkaido] is probably referable to the European species, P. graecense ”, without mentioning any name such as hokkaidoensis or hokkaidoense . The name Prostoma hokkaidoense might have been deemed established by Stiasny-Wijnhoff (1938) via bibliographic reference (Article 13.1.2) to Ishizuka (1933). However, Stiasny-Wijnhoff (1938) recognized only six valid species ( P. lombricoideum , P. puteale , P. grande , P. padanum , P. graecense , and P. eilhardi ), and Prostoma hokkaidoense was not treated as a valid taxon. Therefore, Prostoma hokkaidoense is unavailable under Article 11.5, which requires names to be used as valid when proposed. Nonetheless, Gibson (1995: 496) listed “ Prostoma hokkaidoensis Stiasny-Wijnhoff, 1938 ” as if it were an available name, and Crandall et al. (2002: 14, 21, 29, 43) included “ Prostoma hokkaidoense Stiasny-Wijnhoff, 1938 ” as a valid name. Gibson & Moore (1976: 194), addressing Stiasny-Wijnhoff’s (1938) misconception, correctly noted that “ hokkaidoense is clearly not taxonomically allowable”. However, the issue pertains to nomenclatural status rather than taxonomy.