Bigyra Cavalier-Smith, 1998 Subphylum Opalozoa Cavalier-Smith, 1992 Infraphylum Placidozoa Cavalier-Smith, 2013 Superclass Opalinata Wenyon, 1926 Class Opalinea Wenyon, 1926 Order Proteromonadida Grassé, 1952 [monotypic] 1 Family Proteromonadidae Grassé, 1952 [monotypic]