Prymnesiomonada; Prymnesiida Hibberd 1976; Haptophyceae Christensen 1962 ex Silva 1980; Haptomonadida; Patelliferea Cavalier-Smith 1993] Class Pavlovophyceae Cavalier-Smith 1986 [Pavlovophycidae Cavalier-Smith 1986] Order Pavlovales Green 1976 Family Pavlovaceae Green 1976 Class Prymnesiophyceae Christensen 1962 emend. Cavalier-Smith 1996 [Haptophyceae s.s.; Prymnesiophycidae Cavalier-Smith 1986; Coccolithophyceae Casper 1972 ex Rothmaler 1951] Family †Eoconusphaeraceae Kristan-Tollmann 1988 [Conusphaeraceae] Family †Goniolithaceae Deflandre 1957 Family †Lapideacassaceae Black, 1971 Family †Microrhabdulaceae Deflandre 1963 Family †Nannoconaceae Deflandre 1959 Family †Polycyclolithaceae Forchheimer 1972 emend Varol, 1992 Family †Lithostromationaceae Deflandre 1959 Family †Rhomboasteraceae Bown, 2005 Family Braarudosphaeraceae Deflandre 1947 Family Ceratolithaceae Norris 1965 emend Young & Bown 2014 [Triquetrorhabdulaceae Lipps 1969 - cf Young & Bown 2014] Family Alisphaeraceae Young et al., 2003 Family Papposphaeraceae Jordan & Young 1990 emend Andruleit & Young 2010 Family Umbellosphaeraceae Young et al., 2003 [Umbellosphaeroideae] Order †Discoasterales Hay 1977 Family †Discoasteraceae Tan 1927 Family †Heliolithaceae Hay & Mohler 1967 Family †Sphenolithaceae Deflandre 1952 Family †Fasciculithaceae Hay & Mohler 1967 Order Phaeocystales Medlin 2000 Family Phaeocystaceae Lagerheim 1896 Order Prymnesiales Papenfuss 1955 emend. Edvardsen and Eikrem 2000 Family Chrysochromulinaceae Edvardsen, Eikrem & Medlin 2011 Family Prymnesiaceae Conrad 1926 ex Schmidt 1931 Subclass Calcihaptophycidae Order Isochrysidales Pascher 1910 [Prinsiales Young & Bown 1997] Family †Prinsiaceae Hay & Mohler 1967 emend. Young & Bown, 1997 Family Isochrysidaceae Parke 1949 [Chrysotilaceae; Marthasteraceae Hay 1977] Family Noëlaerhabdaceae Jerkovic 1970 emend. Young & Bown, 1997 [Gephyrocapsaceae Black 1971] Order †Eiffellithales Rood, Hay & Barnard 1971 (loxolith; imbricating murolith) Family †Chiastozygaceae Rood, Hay & Barnard 1973 [Ahmuellerellaceae Reinhardt, 1965] Family †Eiffellithaceae Reinhardt 1965 Family †Rhagodiscaceae Hay 1977 Order Stephanolithiales Bown & Young 1997 (protolith; non-imbrication murolith) Family Parhabdolithaceae Bown 1987 Family †Stephanolithiaceae Black 1968 emend. Black 1973 Order Zygodiscales Young & Bown 1997 [Crepidolithales] Family Helicosphaeraceae Black 1971 Family Pontosphaeraceae Lemmermann 1908 Family †Zygodiscaceae Hay & Mohler 1967 Order Syracosphaerales Ostenfeld 1899 emend. Young et al., 2003 [Rhabdosphaerales Ostenfeld 1899] Family Calciosoleniaceae Kamptner 1927 Family Syracosphaeraceae Lohmann, 1902 [Halopappiaceae Kamptner 1928] (caneolith & cyrtolith; murolith) Family Rhabdosphaeraceae Haeckel, 1894 (planolith) Order †Watznaueriales Bown 1987 (imbricating placolith) Family †Watznaueriaceae Rood, Hay & Barnard 1971 Order †Arkhangelskiales Bown & Hampton 1997 Family †Arkhangelskiellaceae Bukry 1969 Family †Kamptneriaceae Bown & Hampton 1997 Order †Podorhabdales Rood 1971 [Biscutales Aubry 2009; Prediscosphaerales Aubry 2009] (non-imbricating or radial placolith) Family †Axopodorhabdaceae Wind & Wise 1977 [Podorhabdaceae Noel 1965] Family †Biscutaceae Black, 1971 Family †Calyculaceae Noel 1973 Family †Cretarhabdaceae Thierstein 1973 Family †Mazaganellaceae Bown 1987 Family †Prediscosphaeraceae Rood et al.,