Suborder (2) Dysteriina Deroux, 1976

Less conservative in body form (narrower than in first suborder) and in specializations in oral area; definitive adhesive organelle (podite); species widespread and numerous, mainly marine.

Infraciliature Chilodonella-like; adhesive apparatus located centrally in ventral depression.	Family PLESIOTRICHOPIDAE Deroux, 1976
Adhesive organelle posterior, free from ciliary field on left; some uniquenesses in infraciliary patterns; Brooklynella harmful as gill symbiont of marine fishes.	Family HARTMANNULIDAE Poche, 1913
Many species of small body size; general reduction in somatic ciliature; left ciliary field always in two parts; cytopharyngeal capitula often prominent; posteroventral podite may protrude conspicuously; widely distributed organisms, mainly marine, frequently symphorionts.	Family DYSTERIIDAE Claparéde & Lachmann, 1858