Commation eposianum is a species of heterotrophic protists discovered in 1993 in Antarctic waters.

The name of the genus derives from Latin comma, which references the general biconvex shape of the cell.

[1] Commation eposianum is a species of unicellular eukaryotes composed of spherical biconvex cells measuring 7–12 μm.

Their cytoskeleton consists of a spiralling band composed of a microtubular sheet associated with 3 crystalline, electron-dense structures.

The cell has only one type of extrusome which is not visible under light microscopy, in contrast to Commation cryoporinum which presents two types of extrusomes that can be visible if large enough.