Suborder (2) Sporadotrichina Fauré-Fremiet, 1961

(syn. Sporadotrichorina)

Body sometimes elongate, even tailed, but often oval to elliptical in outline; ventral cirri typically heavy and conspicuous and arranged in specific, localized groups; marginal cirri often absent or else reduced; stomatogenesis apokinetal; found in widely diverse habitats (fresh-water, edaphic, marine, interstitial, etc.); a few species are symbiotic, either as ectocommensals on integument (or in branchial caviry) of several invertebrates or as inquilines of echinoids.

Clear-cut rows of right and left marginal cirri; frontoventral and transverse cirri typically heavy and distinctive; zone of adoral membranelles generally restricted to anterior third or quarter of relatively elongate body.	Family OXYTRICHIDAE Ehrenberg, 1838
Generally small forms, with flattened, oval to rounded body; no marginal cirri, but strikingly prominent ventral group(s); reduced number of oral membranelles, located centrally and inconspicuously on ventral surface of body, with apparently no paroral membrane(s); dorsal surface often distinctly ribbed, ridged, or humped; widely distributed in variery of habitats, including echinoid gut and ascidian branchial cavity.	Family ASPIDISCIDAE Ehrenberg, 1838
Marginal cirri absent or greatly reduced in number; transverse and frontoventrals often tremendously developed, heavy, and very conspicuous; oral ciliature also prominent, usually extending more than half the length of the body; intercirral tracts of microtubules; kinetodesmata reported; many species, widely distributed, predominantly marine; Euplotes has been found in sea urchins, and Uronychia in mollusc mantle cavity.	Family EUPLOTIDAE Ehrenberg, 1838
No marginal cirri; other cirri large and in unusual patterns; expansive buccal cavity or peristomial field, with anterior end of body remarkably truncate (most pronounced in Gastrocirrhus); all marine or psammophilic forms.	Family GASTROCIRRHIDAE Fauré-Fremiet, 1961

Incertae sedis in suborder Sporadotrichina:
Allotricha Sterki, 1878, single species;
Cinetoconia Renault & Roche, 1898, single (fossil!) species [very likely not a ciliate at all?];
Gruberella Corliss, 1960 (for Stylocoma), few species;
Onychodromopsis Stokes, 1887, few species,