Division Haptophyta Hibberd
   Class Prymnesiophyceae D.J. Hibberd (1976) see Class Coccolithophyceae Rothm. (1951)
     Subclass Prymnesiophycidae (D.J. Hibberd) Cavalier-Sm. (1986) see Class Prymnesiophyceae D.J. Hibberd (1976)
       "Heterococcoliths"
         "Muroliths"
           Order Zygodiscales Young & Bown (1997)
             Family †Zygodiscaceae Hay & Mohler (1967)