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 Corethrophycidae Round & R.M. Crawford (1990) Order Corethrales Round & R.M. Crawford (1990) 1 Family Corethraceae M. Lebour (1930)