Cap 17

anterior end; free-swimming, typically gliding 
on the substrate; somatic ciliation on both sides 
of the body, typically more densely on the right 
side ; brosse, dorsal, and integrated in one or two 
dorsolateral kineties; oral region, ventral and 
elongated, with oral kinetids as left and right 
components extending along the ventral edge of 
the laterally flattened body, bordering a vent- 
or slit-like cytostome, surrounded by toxicysts ; 
micronucleus lying between two macronuclear 
nodules ; voracious carnivores; in marine, freshwa-
ter, and rarely terrestrial habitats; two families. 
NOTE : Strüder-Kypke et al. (2006) have con-
firmed that this order is monophyletic based on 
small subunit rRNA gene sequences. However, it 
emerges from a paraphyletic haptorid clade. 
 Family AMPHILEPTIDAE Bütschli, 1889 
 Size, small to large; shape, elongate ovoid, often 
flattened and with narrowing at the anterior and 
posterior ends; free-swimming, typically gliding 
on the substrate; somatic ciliation, holotrichous, 
with right somatic kineties converging on a 
secant system, the spica, in the anterior middle 
of the right side ; extrusomes as somatic muco-
cysts and oral toxicysts; oral region along ventral 
“edge” with one right and one left perioral 
kinety, both composed of dikinetids, border-
ing the cytostome ; macronucleus, typically two 
ellipsoid nodules; micronucleus in between macro-
nuclear nodules; contractile vacuole, present; cyto-
proct (?); feeding on flagellates and other ciliates, 
sometimes specializing on peritrich ciliates; in 
marine and freshwater habitats; seven genera. 
 – Amphileptiscus Song & Bradbury, 1998 
 – Amphileptus Ehrenberg, 1830 
372 17. The Ciliate Taxa Including Families and Genera
 – Apoamphileptus Lin & Song, 2004 *
 – Epiphyllum Lin, Song, & Warren, 2005 * [junior 
homonym of anthozoan ] 
 – Kentrophyllum Petz, Song, & Wilbert, 1995 
 – Opisthodon Stein, 1859 
 – Pseudoamphileptus Foissner, 1983 
 Family LITONOTIDAE Kent, 1882 
 (syn. Loxophyllidae ) 
 Size, typically medium to large; shape, flattened 
ovoid with narrowing at the anterior and posterior 
ends; free-swimming, typically gliding on the sub-
strate; somatic ciliation, holotrichous, with right 
somatic kineties gradually terminating along 
rightmost perioral kinety, thus spica absent, and 
with one or two dorsolateral kineties in some 
forms ; extrusomes as somatic mucocysts and somatic 
and/or oral toxicysts, but toxicysts in some forms 
distributed on the perimeter of the flattened body in 
protuberances (e.g., Loxophyllum ); oral region along 
the ventral edge, with two right perioral kine-
ties and one left perioral kinety, with rightmost 
perioral kinety of monokinetids and other kineties 
of dikinetids ; macronucleus, typically two ellip-
soid nodules; micronucleus in between macronuclear 
nodules; contractile vacuole, present; cytoproct (?); 
feeding on flagellates and smaller protists; in marine, 
freshwater, and terrestrial habitats, with some species 
planktonic; five genera. 
 – Acineria Dujardin, 1841 
 – Heminotus Kahl, 1933 
 – Litonotus Wresniowski, 1870 
 – Loxophyllum Dujardin, 1841 
 – Siroloxophyllum Foissner & Leipe, 1995 
Incertae sedis in Subclass Haptoria 
 – Baznosanuia Tucolesco, 1962 
 – Celerita Tucolesco, 1962 
 – Racovitzaiella Aescht, 2001 
Incertae sedis in Subclass Haptoria 
 Order Cyclotrichiida Jankowski, 1980 
 (syn. Mesodiniida ) 
 Size, small to medium; shape, globular to sub-
spheroid; free-swimming; somatic cilia, bristle-like, 
of at least two types, arranged in girdles around 
the body ; brosse kineties absent; extrusomes as oral 
toxicysts; oral region, apical, domed, circular, and 
delimited by circumoral dikinetids, but apparently 
without nematodesmata and bulge microtubules 
of rhabdos ; macronucleus, ellipsoid to band-shaped; 
micronucleus, present; contractile vacuole, present; 
cytoproct (?); feeding on flagellates and microalgae, 
and sometimes containing symbiotic algae; plank-
tonic in marine and freshwater habitats; one family. 
NOTE : Johnson, Tengs, Oldach, Delwiche, 
and Stoecker (2004) have demonstrated that the 
small subunit rRNA sequences of two Mesodinium
species are highly divergent to other haptorian 
sequences, placing them at a basal position in the 
phylum. Based on the presence of toxicysts and 
features of the secondary structure of the small 
subunit rRNA molecule, which suggest homology 
to the litostomes (see Strüder-Kypke et al., 2006), 
we are maintaining these ciliates in the Subclass 
 Haptoria until other genes suggest otherwise. 
 Family MESODINIIDAE Jankowski, 1980 
 With characteristics of the order; four genera. 
 – Askenasia Blochmann, 1895 
 – Mesodinium Stein, 1863 
 – Myrionecta Jankowski, 2007 
 – Rhabdoaskenasia Krainer & Foissner, 1990 
 Subclass Trichostomatia Bütschli, 1889 
 (syn. Synciliostoma p.p .) 
 Size, small to large; shape, ovoid to elongate, some-
times with bizarre processes and cell appendages; 
free-swimming; alveoli, typically well- developed, 
often filled with “skeletal” material; somatic cilia-
tion, variable, from holotrichous to reduced to gir-
dles, bands, and tufts, but with somatic kinetids as 
for the class; concrement vacuole(s) present in a few 
forms; extrusomes as somatic mucocysts and oral 
toxicysts absent; oral region or cavity, typically a 
densely ciliated vestibulum, with oral cilia some-
times as “polykinetids” or syncilia ; cytostome, and 
therefore vestibulum, sometimes antapical; stoma-
togenesis, telokinetal, but cryptotelokinetal in ento-
diniomorphids; macronucleus, typically elongate 
ovoid; micronucleus, present; contractile vacuole, 
present; cytoproct, often conspicuous; hydrogeno-
somes, typically replace mitochondria ; feeding on 
bacteria, detritus, plant material ingested by the host, 
and other ciliates; majority of species endocommen-
sals in vertebrate hosts; three orders. 
17.3 The Ciliate Taxa to Genus 373
 Order Vestibuliferida de Puytorac et al., 1974 
 (syns. Balantidiida p.p ., Balantidiina p.p ., 
 Isotrichida p.p ., Isotrichina p.p ., Infundibuloriina 
p.p ., Paraisotrichida p.p ., Rimostomata p.p ., 
 Synciliophora s.l ., Vestibulifera s.l .) 
 Somatic ciliation, holotrichous and dense; cortex, 
often with thick microfilamentous layer between 
ecto- and endoplasm; oral region a depression 
or vestibulum, densely ciliated by extensions 
of somatic kineties, whose cilia do not appear 
organized as “polykinetids” ; cytostome at base 
of vestibular cavity; endocommensals in herbivo-
rous placental mammals, but not in marsupials, 
with balantidiids endocommensals in selected 
vertebrates from fish to great apes, but parasitic 
in humans at least ; six families. 
 Family BALANTIDIIDAE Reichenow in Doflein 
& Reichenow, 1929 
 (syn. Paranyctotheridae ) 
 Size, small to medium; shape, ovoid to elon-
gate; free-swimming; somatic ciliation, holotri-
chous, with clavate cilia in several kineties, as 
possible homologues of the haptorian brosse; no 
concrement vacuole; extrusomes as somatic muco-
cysts; oral cavity apico-ventral, as a vestibu-
lar groove less than one-half body length and 
lined by extensions of somatic kineties, which 
are accompanied by supernumerary kineties ; 
macronucleus, elongate ellipsoid; micronucleus, 
present; contractile vacuole, present; cytoproct, 
likely absent; encystment probable; feeding on 
bacteria and organic detritus, but also may feed on 
host intestinal epithelial cells; in marine, freshwa-
ter, and terrestrial habitats as endocommensals in 
the digestive tracts of diverse hosts, such as insects , 
 fish , frogs , snakes , guinea pig , pig , monkey , chim-
panzee , gorilla , and orang-utang , and parasitic at 
least in man; three genera. 
 – Balantidium Claparède & Lachmann, 1858 
 – Dilleria Earl, 1973 
 – Metacollinia Jankowski, 1980 
 Family ISOTRICHIDAE Bütschli, 1889