[2] This unicellular algal species was discovered in 1990 in the West Pacific Ocean and has characteristic reproduction methods as well as an interesting and potentially exploitable morphology.

[3] Prasinococcus capsulatus, the only currently known member of this genus, was discovered in the West Pacific Ocean during a cruise by the research vessel Sohgen-maru in November–December 1990.

The mitochondrial lobe and chloroplast outer membrane both protrude into the pyrenoid matrix which is considered characteristic of the genus.

Capsulan is thought to be synthesised in the Golgi and then secreted through the decapore (a specialised circle of 10 pores through the cell wall).

In similar species, capsules have been noted for their antibacterial properties [4] and a conspicuous lack of bacteria as well as viral particles in impure samples of P. capsulatus has been observed.