Domain Eucaryota
   Subdomain Chlorota Doweld (2001)
     Kingdom Peridiniobiota Starobogatov ex Doweld (2001)
       Subkingdom Parameciobiotina Starobogatov, 1986 [monotypic]
         Phylum Parameciozoa Kussakin & Drozdov, 1998
           Subphylum Oxytrichozoina Doweld, 2001
             Class Spathidiatea Doweld, 2001
               Subclass Spathidiatinea Doweld, 2001
                 Order Spathidiida Foissner & Foissner, 1988
                   Family Spathidiidae Kahl, 1929
                     Genus Spathidium Dujardin, 1841