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tion into zig-zag folds in one plane; zooids in 
colonial forms, sharing continuous spasmoneme 
that runs throughout the entire colony, so that 
the entire colony is contractile ; some colonial 
species dimorphic, forming macrozooids, spe-
cialized for producing telotrochs or conjugants; 
oral region as for subclass, but with a retractable 
peristomial lip and slightly protuberant epistomial 
disk; macronucleus, band-shaped; micronucleus, 
present; contractile vacuole, present; cytoproct 
(?); in marine and freshwater habitats, attached to 
inanimate objects, plants, rotifers , crustaceans , and 
even turtles ; eight genera. 
 – Craspedomyoschiston Precht, 1935 
 – Haplocaulus Warren, 1988 
 – Mesothamnium Jankowski, 1985 
 – Myoschiston Jankowski, 1985 
 – Pseudohaplocaulus Warren, 1988 
 – Zoothamnioides Schoedel, 2006 *
 – Zoothamnium Bory de St. Vincent, 1824 
 – Zoothamnopsis Song, 1997 
 Order Mobilida Kahl, 1933 
 (syns. Dentodiscida , Mobilia , Mobiliida , Mobilina , 
 Mobilorina , Trichodinina p.p ., Urce olariellina 
p.p .) 
 Size, medium; shape, conical, cylindrical, or 
goblet-shaped, sometimes discoidal and orally-
aborally flattened; zooid, mobile, comparable to 
permanent telotroch stage of Order Sessilida, 
with permanently ciliated trochal band, typi-
cally composed of three rings of cilia ; adhesive 
disk on aboral pole, slightly contractile to ena-
ble temporary attachment, its dominant feature 
being a ring-like, complex skeletal armature 
of denticles and fibers surrounding a vestigial 
scopula ; oral region as for subclass, but not 
contractile; oral structures with infundibular 
portions of oral polykinetids 1 and 2 always run-
ning together in a “ribbon” and oral polykinetid 
3, short, perpendicular to the other two oral 
polykinetids ; bacterivorous, obtaining prey from 
water or from detritus adhering to the host, and 
microphagous, on cellular debris from host; cysts 
not observed; in marine and freshwater habitats as 
ectosymbionts, often on the integument or gills of 
invertebrates, but other groups, including other cili-
ates, amphibians , and fishes , and other locations, 
434 17. The Ciliate Taxa Including Families and Genera
such as the digestive and urogenital tracts, may 
also be colonized, sometimes pathogenic in heavy 
populations; five families. 
 Family LEIOTROCHIDAE Johnston, 1938 
 Size, medium; shape, cylindrical or barrel-
shaped, with slightly bulging apical end and 
pellicular rings around the body ; adhesive disk 
with ca . 20 smooth denticles, simple in shape, sur-
rounding ciliated scopula; oral ciliature forming 
a spiral of ca . 400°, with radius equal to that 
of the adhesive disc ; macronucleus, bulbous 
with two arms, roughly H-shaped ; micronucleus 
(?); contractile vacuole, present; cytoproct (?); in 
marine habitats, widespread as symbionts on the 
gills of molluscs and on scattered other inverte-
brates (e.g., on spines of sea urchins ); one genus. 
 – Leiotrocha Fabre-Domergue, 1888 (subj. syn. 
Trichodina ) 
 Family POLYCYCLIDAE Poljansky, 1951 
 Size, small; shape, conical, tapered apically, 
with pellicular rings around the body ; adhesive 
disk with 35–60 smooth denticles, densely linked, 
simple in shape, surrounding scopula with vibratile 
cilia; trochal band(s), in two distinctly separate 
girdles ; oral ciliature, deeply invaginated and 
so relatively inconspicuous, forming a spiral of 
ca . 360°, with greatly reduced radius ; macronu-
cleus, ribbon-like and L-shaped ; micronucleus 
(?); contractile vacuole (?); cytoproct (?); in marine 
habitats as endocommensals in the digestive tract 
of holothurian echinoderms (e.g. Synapta ); one 
 – Polycycla Polijansky, 1951 
 Family TRICHODINIDAE Claus, 1874 
 Size, small; shape, cylindrical, barrel-, or gob-
let-shaped, occasionally slightly tapered apically 
or flattened into discoidal or hemispherical form; 
adhesive disk with ca . 15–60 denticles, complex in 
shape with a central part with or without an inner 
spine, and flattened outer blade, often linked to 
each other by hooks and/or spikes, surrounding a 
non-ciliated scopula ; oral ciliature, conspicuous, 
consisting of a spiral ranging from a half-turn 
of ca . 180° to 2–3 nearly full circles, always with 
a wide radius, equal to that of aboral adhesive 
disc ; macronucleus, sausage- to horseshoe-shaped; 
micronucleus, present; contractile vacuole, present; 
cytoproct (?); in marine and freshwater habitats, 
widely distributed on a diversity of hosts, such as 
other ciliates and the integument of various aquatic 
invertebrates, also on the surfaces of the skin, uri-
nary bladder, and especially gills of fishes and a few 
 amphibians , and even the mantle cavity of terrestrial 
 gastropod molluscs ; 11 genera. 
NOTE : Guhl and Haider (1988) placed Urc-
eolaria in this family instead of the Family 
 – Dipartiella G. Stein, 1961 
 – Hemitrichodina Basson & Van As, 1989 
 – Pallitrichodina Van As & Basson in Aescht, 2001 
 – Paratrichodina Lom, 1963 
 – Semitrichodina Kazubski, 1958 
 – Teretrichodina Jankowksi, 1980 
 – Trichodina Ehrenbeg, 1830 
 – Trichodinella Šrámek-Hušek, 1953 
 – Trichodoxa Sirgel, 1983 
 – Tripartiella Raabe, 1963 
 – Vauchomia Mueller, 1938 
 Family TRICHODINOPSIDAE Kent, 1881 
 Size, medium; shape, conical, tapered apically, 
with pellicular rings; adhesive disk with 30–40, 
smooth denticles, densely linked, surrounding some 
scopulary cilia and with one trochal band; oral cilia-
ture, relatively inconspicuous, consisting of a spiral of 
ca . 360°, with greatly reduced radius; infundibulum, 
highly specialized, with bulbous expansion poste-
riorly so that the oral ciliature follows a U-shaped, 
rather than a helical, trajectory, which moves the 
cytostome into an almost apical position ; macronu-
cleus, compact, discoidal; micronucleus (?); contrac-
tile vacuole (?); cytoproct (?); in terrestrial habitats as 
intestinal symbionts of a terrestrial prosobranch snail 
(e.g. Cyclostoma ); one genus. 
 – Trichodinopsis Claparède & Lachmann, 1858 
(subj. syn. Urceolaria ) 
 Family URCEOLARIIDAE Dujardin, 1840 
 Size, small to medium; shape, cylindrical, often 
slightly tipped to one side; adhesive disk with 
ca. 20, smooth denticles, simple in shape, and 
with no scopulary cilia ; adoral spiral making a 
17.3 The Ciliate Taxa to Genus 435
circuit of ca. 360–400°, with wide radius ; macro-
nucleus, discoid or band-shaped; micronucleus, 
present; contractile vacuole, present; cytoproct (?); 
in marine and freshwater habitats as ectosymbionts 
of turbellarians and the gill surfaces of polychaetes 
and molluscs ; four genera. 
 – Anthurceolaria Jankowski, 1980 
 – Monurceolaria Jankowski, 1980 [not listed in 
 – Orthurceolaria Jankowski, 1980 
 – Urceolaria Stein, 1867 
 Subclass Astomatia Schewiakoff, 1896 
 (syns. Astomat[e]a , Astom[at]ina ) 
 Size, small to large, often worm-like; shape, cylin-
drical or flattened-ovoid; free-swimming, but often 
attached to host tissues; somatic ciliation, holotri-
chous, dense, often with a thigmotactic zone; an 
infraciliary endoskeleton of considerable complex-
ity may be present, frequently with an elaborate, 
anterior holdfast organelle ; mouthless ; fission, 
often anisotomic, sometimes catenulate; macronu-
cleus, elongate, often extending length of cell; con-
tractile vacuoles, often in one or two rows or as a 
long canal ; cytoproct, absent ; cysts reported in some 
species; osmotrophic ; in marine, brackish, freshwater, 
and terrestrial habitats with the majority of species as 
endosymbionts in the digestive tracts of oligochaetes, 
but some species in polychaetes , leeches , turbellarians 
or molluscs , and one major group exclusively in tailed 
 amphibians ; complete life cycle not yet described, but 
presumed to be direct; one order. 
NOTE : The monographic works of Cépède