After Parker, 1982

<==o Gragarinia
   |--o Archigregarinida
   |  |-- Selenidioididae
   |  `-- Exoschihizonidae
   |--o Eugregarinida
   |  |-- Siedleckiidae [Blastogregarinina]
   |  |--o Acephalina
   |  |  |-- Selenidiidae
   |  |  |-- Lecudinidae
   |  |  |-- Urosporidae
   |  |  |-- Aikinetocystidae
   |  |  |-- Monocystidae
   |  |  |-- Diplocystidae
   |  |  |-- Allantocystidae
   |  |  |-- Schaudinnellidae
   |  |  |-- Ganymenidae
   |  |  `-- Enterocystidae
   |  `--o Cephalina
   |     |-- Porosporidae [Porosporoidea]
   |     |-- Fusionidae [Fusionoidea]
   |     |--o Gregarinoidea
   |     |  |-- Cephaloidophoridae
   |     |  |-- Cephalolobidae
   |     |  |-- Uradiophoridae
   |     |  |-- Gregarinidae
   |     |  |-- Metameridae
   |     |  |-- Didymophyidae
   |     |  `-- Hirmocystidae
   |     `--o Stenophoroidea
   |        |-- Stenophoridae
   |        |-- Leidyanidae
   |        |-- Cnemidosporidae
   |        |-- Monoductidae
   |        |-- Sphaerocystidae
   |        |-- Trichorhynchidae
   |        |-- Dactylophoridae
   |        |-- Stylocephalidae
   |        |-- Actinocephalidae
   |        |-- Acutidae
   |        `-- Monoicidae
   `--o Neogrerarinida
      |-- Lipotrophidae
      |-- Gigaductidae
      |-- Ophryocystidae
      |-- Schizocystidae
      |-- Caulleryellidae
      `-- Syncystidae

Reference(s):