Division Bacillariophyta Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919)
Count: 3c;45o;91f;291g;308s
   Class Coscinodiscophyceae Round & R.M. Crawford (1990) - radial centrics
  Count: 22o;40f;122g;1s
     Subclass Thalassiosirophycidae Round & R.M. Crawford (1990) see Class Mediophyceae Medlin & Kaczmarska (2004)
    Count: [f] 1o;4f;14g
       Order Thalassiosirales Glezer & I.V. Makarova (1986)
      Count: [f] 4f;14g
         Family Stephanodiscaceae Glezer & Makarova (1986)
        Count: 6g
           Genus Cyclostephanos Round (1987)
          Count: -