chromalveolates see Supergroup Chromalveolata Adl et al., 2005
   Kingdom Chromista Caval.-Sm. (1981) - chromists
     Subkingdom Chromobiota Caval.-Sm. (1991)
       Infrakingdom Heterokonta Caval.-Sm. (1986) - heterokonts see Superphylum Heterokonta Caval.-Sm. (1986)
         Phylum Ochrophyta Caval.-Sm. (1995)
           Subphylum Khakista Caval.-Sm. (2000)
             Class Diatomeae Haeckel (1889) see [unranked] Diatomea Kütz. (1844)
               Genus Coscinodiscus Ehrenb. (1839)