eukaryotes see Domain Eukaryota Chatton, 1925
   Kingdom Protozoa Goldfuss, 1818 [paraphyletic] - protozoa
     Subkingdom Sarcomastigota Cavalier-Smith, 1983 [paraphyletic] see [unranked] dorsates Cavalier-Smith, 2021
       Infrakingdom Diacentrida Cavalier-Smith, 2021 [paraphyletic] see [unranked] torcids Cavalier-Smith, 2021
         Phylum Apusozoa Cavalier-Smith, 1997 [paraphyletic?] see Clade Obazoa Brown, Sharpe, Silberman, Heiss, Lang, Simpson & Roger 2013
           Class Breviatea Cavalier-Smith, 2004 - breviates
             Family Pygsuidae Cavalier-Smith, 2021 [monotypic]
               Genus Pygsuia Brown, Sharpe, Silberman, Heiss, Lang, Simpson & Roger, 2013