Kingdom Protoctista Hogg, 1860 Phylum Bacillariophyta Engl. & Gilg (1919) - diatoms see [unranked] Diatomea Kütz. (1844) Class Coscinodiscophyceae Round & R.M. Crawford (1990) - radial centrics Subclass Biddulphiophycidae Round & R.M. Crawford (1990) see Class Mediophyceae Medlin & Kaczmarska (2004) Order Eupodiscales see Order Triceratiales Round & R.M. Crawford (1990) Family Eupodiscaceae Ralfs (1861), nom. cons. see Family Triceratiaceae Lemmerm. (1899) Genus Triceratium Ehrenb. (1839)