Division Bacillariophyta Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919)
   Class Fragilariophyceae Round (1990) - araphid, pennate diatoms see Class Bacillariophyceae Haeckel (1878)
     Subclass Fragilariophycidae Round (1990) - core araphid diatoms
       Order Rhaphoneidales Round (1990)
         Family Psammodiscaceae Round & D.G.Mann (1990)
           Genus Psammodiscusᵀ Round & D.G.Mann (1980)