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 Chaetocerophycidae see Subclass Chaetocerotophycidae Round & R.M. Crawford (1990)
         Order Chaetocerotales Round & R.M. Crawford (1990)
           Family Chaetocerotaceae Ralfs (1861)
             1 Genus Chaetoceros Ehrenb. (1844)
             2 Genus Bacteriastrum Shadbolt (1854)