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 heterolobum