Class Dinophyceae Pascher (1914) Order Peridiniales Haeckel (1894) Family Pyrophacaceae Er. Lindem. (1928) see Family Pyrocystaceae (F. Schütt) Lemmerm. (1899) Genus Fragilidium Balech ex A.R. Loebl. (1965) Fragilidium mexicanum Balech (1988)