Bigyra Cavalier-Smith, 1998
   Subphylum Opalozoa Cavalier-Smith, 1992
     Infraphylum Bikosia Cavalier-Smith, 2013 [monotypic]
       Class Bikosea Cavalier-Smith, 2013
         Subclass Bicosidia Cavalier-Smith, 2006
           Superorder Cyathobodoniae Cavalier-Smith, 1993
             Order Pseudodendromonadida Hibberd, 1985
               Family Nanidae Cavalier-Smith, 2013 [monotypic]
                 Genus Nanum Cavalier-Smith, 2013 [monotypic]
                   Nanum amicum (Kim, Yubuki, Leander & Graham, 2010)