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 Protoraphidales Round (1990) see Order Protoraphidales Round ex Gogorev (2015)
         1 Family Protoraphidaceae Simonsen (1970)