Minorisa minuta

The generic name Minorisa comes from the town Manresa, the birthplace of Javier del Campo, who first described the genus in 2013.^[1] The specific epithet minuta, Latin for tiny, refers to the small size of the organism.^[1]

Minorisa minuta is a unicellular organism with naked and spherical, ellipsoid or ovoid cells.^[1] They are minuscule, only 1–2.9 micrometers long and 0.8–2.3 micrometers wide.^[2] It possesses a single flagellum that can be up to four times its length.^[1] Minorisa swims by rotating along its longitudinal axis.

Minorisa minuta has an amoeboid life stage. This amoeboid stage has lobose and extrusive pseudopodia.^[2]

Molecular phylogenetics places Minorisa minuta at the base of the Chlorarachniophytes.^[1] Minorisa is the only heterotrophic representative within the Chlorarachniophytes, which is the only photosynthetic group within the supergroup Rhizaria.^[1] It is unknown whether Minorisa posteriorly lost the plastid or whether the lack of a plastid in Minorisa indicates a second instance of acquisition of a green plastid independently in Chlorarachniophytes.^[1]