Family TRICHODINIDAE Claus, 1874

Body cylindrical, barrel-, or goblet-shaped, occasionally slightly tapered apically or flattened into discoidal or hemispherical form; adoral spiral ranges from turn of 180° to 2-3 nearly full circles, always with wide radius (matching that of aboral adhesive disc); buccal ciliature conspicuous; denticles complex, often linked via hooks and/or spikes, generally 15-40 in number (but approaching 60 in several genera); no scopulary but often marginal cilia; macronucleus sausage- to horseshoe-shaped (sometimes compact); numerous species, widely distributed and found in diversity of hosts (e.g., Trichodina: others often with higher host-specificity): other ciliates and integument of various aquatic invertebrates, plus mantle cavity of land gastropod molluscs, to skin, urinary bladder, and especially gills of marine and fresh-water fishes and a few amphibians.

Dipartiella G. Stein, 1961 (syn. Dogielina [hom.] ). Few species. XXIX 128d.
Paratrichodina Lom, 1963. Several species.
Semitrichodina Kazubski, 1958. Few to several species. IV 21c
Trichodina Ehrenberg, 1830 (syns. Anhymenia, Cyclochaeta, Cyclocyrrha, Paravauchomia, Poljanskina). Very many (ca. 200) species described. IV 21a, 22a, XXIX 128a.
Trichodinella Srámek-Husek, 1953 (for Brachyspira; syn. Foliella). Several species. IV 21b,XXIX 128c.
Tripartiella Lom, 1959. Several species. IV 21b,XXIX 128b.
Vauchomia Mueller, 1938. Few species. IV 21d
Incertae sedis:
Acyclochaeta Zick, 1928. Single species.