Parent taxon: Diatomophyceae according to M. -J. Chrétiennot-Dinet et al. 1993
See also Andrews 1976
Sister taxa: Acanthodiscus, Achnanthales, Anaulales, Annellus, Arachnoidiscales, Asterolamprales, Aulacodiscaceae, Aulacoseirales, Bacillariales, Bacillariophycidae, Baxteria, Biddulphiales, Cavitatus, Chaetocerotaceae, Corethrales, Corinna, Coscinodiscales, Cresswellia, Cussia, Cyclophorales, Cymatodiscus, Cymatosirales, Cymbellales, Detonia, Dextradonator, Diatomaceae, Dicladia, Discodiscus, Dispinodiscus, Entogonia, Epithelion, Ethmodiscales, Eunotiales, Eurossia, Eustephaniaceae, Fenestrella, Fenestrellina, Fragilariales, Gladius, Glyphodiscus, Goniothecium, Helminthopsis, Hemiaulales, Hemidiscaceae, Hendeya, Horodiscus, Huttonia, Ikebea, Incisoria, Kannoa, Katahiraia, Kentrodiscus, Kittonia, Kozloviella, Leptocylindrales, Licnophoridae, Liostephania, Liradiscus, Liriogramma, Lithodesmiales, Longinata, Mastogloiales, Melosirales, Monobrachia, Muelleriopsis, Naviculales, Neobrunia, Odontotropis, Omphalotheca, Paraliales, Peponia, Poretzkia, Porotheca, Praecymatosira, Pseudodimerogramma, Pseudopyxilla, Pseudostictodiscus, Pterotheca, Pyrgodiscus, Raphidineae, Rhabdonematales, Rhaphoneidales, Rhizosoleniales, Rhoicosphenia, Rhopalodiales, Rouxia, Schimperiella, Simonseniella, Solium, Stictodiscales, Striatellales, Surirellales, Symbolophora, Tabellariales, Thalassionematales, Thalassiophysales, Thalassiosirales, Thalassiosiropsis, Triceratiales, Trinacria, Trochosiropsis, Tubaformis, Tubulariidae, Tumulopsis, Vulcanella, Xanthiopyxis, Heterales, Pennales
Subtaxa: Auliscineae Basilicostephanus Chaetoceraceae Cladogramma Discineae Eupodiscaceae Eupodiscineae Hemiauliineae Lithodemiaceae Rutilaria Sheshukovia Strelnikovia Triceratiineae
Ecology: passively mobile planktonic "photoautotroph"