Phylum: Bacillariophyta (Diatoms)
The taxonomy presented here follows AlgaeBase as at early August 2026. Doubtless many new species await discovery and formal description, and this may necessitate the erection of novel higher taxonomic ranks.
Class: Bacillariophyceae
Order: Cymbellales
Family: Cymbellaceae
| Scientific Name & Authority | Common Name/s | Distribution (Habitat) | Status (Last Record) | Taxon Profile |
| Alveocymba mirabilis (Hustedt) Kapustin, Kulikovskiy & Kociolek (2020) | - | Lake Matano & Lake Towuti, Indonesia | Rediscovered | Access |
Families: Anomoeoneidaceae, Encyonemataceae, Gomphonemataceae, Rhoicospheniaceae, Witkowskiaceae
—No subordinate taxa
Orders: Achnanthales, Bacillariales, Cocconeidales, Diadesmidales, Dictyoneidales, Diploneidales, Lyrellales, Mastogloiales, Naviculales, Rhopalodiales, Sellaphorales, Surirellales, Thalassiophysales
—No subordinate taxa
Class: Thalassiosirophyceae
Order: Thalassiosirales
Family: Thalassiosiraceae
| Scientific Name & Authority | Common Name/s | Distribution (Habitat) | Status (Last Record) | Taxon Profile |
| Stephanodiscus flabellatus Khursevich & Loginova (1986) | - | Lake Baikal, southern Siberia, Russia | Extinct (Late Pleistocene) | Access |
Classes: Corethrophyceae, Coscinodiscophyceae, Fragilariophyceae, Leptocylindrophyceae, Melosirophyceae, Plagiogrammaphyceae, Striatellaphyceae
—No subordinate taxa
Statistics
| Conservation status | Number of taxa (in percentage) |
| Extinct | 1 (50%) |
| Missing | 0 |
| Extinct in the Wild | 0 |
| Possibly Extinct in the Wild | 0 |
| Globally Rediscovered | 1 (50%) |
| Rediscovered in the Wild | 0 |
| Reintroduced | 0 |
| Uncertain status | 0 |
| Hypothetical | 0 |
| Total | 2 (100%) |
| Erroneously listed | 0 |
| Invalid | 0 |
| Grand total | 2 (100%) |