oligochaetocystinae oligochaetocystinae oligochaetocystinae is a subfamily of parasites in the phylum apicomplexa. oligochaetocystinae scientific classification domain: eukaryota clade: diaphoretickes clade: sar clade: alveolata phylum: apicomplexa class: conoidasida order: eugregarinorida family: monocystidae subfamily: oligochaetocystinaemeier, 1956 genera see text taxonomy there are four genera in this subfamily: acarogregarina echiurocystis neomonocystis oligochaetocystis description the oocysts are cylindrical without thickening at ends.