Bacillariophyceae

Bacillariophyceae Temporal range: Cretaceous–Recent PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Clade:	Sar
Clade:	Stramenopiles
Division:	Ochrophyta
Clade:	Diatomeae
Subdivision:	Bacillariophytina
Class:	Bacillariophyceae Haeckel 1878, emend. Adl et al. 2019[1]
Subclasses and families[1][2]
Urneidophycidae Fragilariophycidae Bacillariophycidae Striatellaceae

Bacillariophyceae is a class of diatoms.[1] Previously, this class was equivalent to Diatomeae, the taxonomic name for all diatoms.[3] However, due to both the known and estimated diversity of diatoms, since 2019 they have been expanded to several classes.[4] In particular, Bacillariophyceae was given the following modified diagnosis:[1]

"Chain-forming, colonial or solitary; valve outline almost always bipolar; valve pattern organized bilaterally about an elongate axial rib (sternum), as in a feather; valve structure simple or chambered; rimoportulae generally only one or two per valve or none, sometimes accompanied (or replaced?) by special slits (the 'raphe') involved in motility; sexual reproduction involving gametangiogamy and almost always with gametes of equal size (although sometimes with behavioral differentiation and/or morphological differences); perizonium generally differentiated into two distinct series, transverse and longitudinal; chloroplasts usually only one, two or a few and large, less often many and small."