Raphidocelis subcapitata

Raphidocelis subcapitata, formerly known as Selenastrum capricornutum and Pseudokirchneriella subcapitata is a microalga.^[1] This microalga presents a curved and twisted appearance like a sickle. The cells are normally presented in a solitary form in culture, although it may also be present in small colonies. It has a length between 7 and 15 μm, and a width between 1.2 and 3 μm. A single chloroplast is present, filling nearly the entire cell; it lacks a pyrenoid.^[2] It is commonly used as a bioindicator species to assess the levels of nutrients or toxic substances in fresh water environments. This species is quite sensitive to the presence of toxic substances including metals and has a ubiquitous distribution, so is broadly used in ecotoxicology.^[3][4] This species has been found to be more competitive than Chlorella vulgaris at low sodium chloride concentrations, but C. vulgaris was more competitive under salt stress.^{[5][non-primary source needed]}

Raphidocelis subcapitata
Scientific classification
Kingdom:	Plantae
Division:	Chlorophyta
Class:	Chlorophyceae
Order:	Sphaeropleales
Family:	Selenastraceae
Genus:	Raphidocelis
Species:	R. subcapitata
Binomial name
Raphidocelis subcapitata (Korshikov) Nygaard, Komárek, J.Kristiansen & O.M.Skulberg
Synonyms
Kirchneriella subcapitata Korshikov Pseudokirchneriella subcapitata (Korshikov) Hindák