Position in a system
| system | Vitae - living organisms |
| domain | Eukaryota Whittaker & Margulis, 1978 - lifeforms with nucletic cells |
| superregnum | Bikonta - bikonts |
| Corticata | |
| kingdom | Chromalveolata Adl et al., 2005 |
| phylum | Heterokontophyta |
| subphylum | Diatomeae (Dumortier, 1821) Cavalier-Smith, 1995 - diatoms |
| class | Coscinodiscophyceae Round & Crawford, 1990 |
| subclass | Coscinodiscophycidae Round & Crawford 1990 |
| order | Orthoseirales Crawford 1990 |
| family | Orthoseiraceae Crawford 1990 |
| genus | Orthoseira G.H.K. Thwaites, 1848 |