grasseella grasseella grasseella is a genus in the phylum apicomplexa. grasseella scientific classification domain: eukaryota clade: diaphoretickes clade: sar clade: alveolata phylum: apicomplexa class: conoidasida order: eucoccidiorida family: aggregatidae genus: grasseellatuzet and ormières, 1960 species: g. microcosmi binomial name grasseella microcosmituzet and ormières, 1960 history this genus was created by tuzet and ormières in 1960. taxonomy there is one species recognised in this genus. description this species infects an ascidian worm (microcosmus sulcatus). the oocysts have many sporocysts, each with 2 sporozoites.