Revision of the genus Eucyclops (Claus, 1893) and subfamily Eucyclopinae of the world fauna

The revision of the most rich with species genus Eucyclops Claus, 1893 was done. The genus Austriocyclops Kiefer, 1964 has been moved back to the subfamily Cyclopinae, as Kiefer suggested. The status of the genus Australoeucyclops Karanovic, 2006 is lowered to subgenus, and the status of the subgenus Defayeicyclops Alekseev et Vaillant, 2013 is erected to genus. Two new genera (former subgenera) Isocyclops Kiefer, 1957 stat.n. and Stygocyclops Plesa, 1971 stat.n. were erected from the genus Eucyclops. A key for 12 genera of the subfamily Eucyclopinae is given. Genus Eucyclops including about 100 valid species was split into 9 subgenera: Eucyclops (Eucyclops), Eucyclops (Breviramocyclops), Eucyclops (Ciliocyclops), Eucyclops (Denticyclops), Eucyclops (Macrurocyclops), Eucyclops (Mrazekicyclops), Eucyclops (Sarsicyclops), Eucyclops (Speratocyclops), and Eucyclops (Subterrocyclops). Descriptions and illustrations are provided for typical species, as well as keys to 9 new subgenera of Eucyclops genus and to subfamily Eucyclopinae. For each subgenus, the total number of species and identifying keys for them are provided.