Phylum Parabasalia Honigberg, 1973 see Infraphylum Parabasalia Honigberg, 1973
   Class Tritrichomonadea Cepicka, Hampl & Kulda, 2010 see Order Tritrichomonadida Cepicka, Hampl & Kulda, 2010
     Order Tritrichomonadida Cepicka, Hampl & Kulda, 2010 - tritrichomonadids
       Family Dientamoebidae Grassé, 1953
         1 Genus Dientamoebaᵀ Jepps & Dobell, 1918
         2 Genus Protrichomonas Alexeieff, 1911
         3 Genus Histomonas Tyzzer, 1920
         4 Genus Parahistomonas Honigberg & Kuldová, 1969