After Parker, 1982

<==o Orthonectida Giard, 1880 [Mesozoa van Beneden, 1877 (in partim)] (harvasoluiset 2)
   |--o Rhopaluridae [Orthonectidae]
   |  `--o Rhopalura
   |     |-- R. ophiocomae
   |     `-- R. granosa
   `-- Pelmatosphaeridae [Heteronectidae]

Reference(s):