Cap 17

shallow 
depression; oral polykinetids reduced, with oral 
polykinetid 1 typically non-ciliated and with 
relatively inconspicuous oral ciliature on the 
other two oral polykinetids ; scutica, a trian-
gular arrangement of ciliated kinetosomes in 
the director meridian ; macronucleus, globular 
to ellipsoid; micronucleus, present; contractile 
vacuole, present; cytoproct, present; bacterivorous; 
in marine, freshwater, and occasionally terrestrial 
habitats; seven genera. 
 – Homalogastra Kahl, 1926 
 – Pseuduronema Hoare, 1927 
 – Urocyclon Song & Wilbert, 2000 
 – Uronema Dujardin, 1841 
 – Uronemella Song & Wilbert, 2002 *
 – Uronemopsis Kahl, 1931 
 – Uropedalium Kahl, 1928 
 Family UROZONIDAE Grolière, 1975 
 (syn. Urozonatidae ) 
 Size, very small; shape, ovoid, but well rounded 
at anterior and posterior ends ; free-swimming; 
somatic ciliation as a series of short kineties, 
forming a single equatorial belt of somatic 
ciliature; caudal cilium, single, long; oral region 
as deep equatorial cavity with two oral polyki-
netids of two rows of kinetosomes, transverse 
to the longitudinal axis of the oral region ; scu-
tica of several kinetosomes in “V” configuration; 
macronucleus, globular; micronucleus, present; 
contractile vacuole, present; cytoproct, present; 
bacterivorous; in freshwater polysaprobic habitats; 
one genus. 
 – Urozona Schewiakoff, 1889 
Incertae sedis in Order Philasterida
 – Andreula Kahl, 1934 
 – Bizonula Corliss, 1960 
 – Cryptostomina Fedele, 1938 
 – Eurychilum André, 1910 
 – Lembadionella Kahl, 1933 
 – Ptyssostoma Hentschel, 1927 
 – Pusilloburius Corliss, 1979 
 – Rhinodisculus Mansfeld, 1923 
 – Sertumia Tucolesco, 1962 
 Order Pleuronematida Fauré-Fremiet in Corliss, 
1956
 (syns. Conchophthiriina p.p ., Deuterostomatina 
p.p ., Pleuronematorina ) 
 Size, very small to medium, with occasional 
striking exceptions; shape, ovoid; free-swimming, 
but with some forms restricted to loricae; somatic 
ciliation, holotrichous, but often more sparse 
posteriorly, with thigmotactic ciliation often well 
developed in some taxa; caudal cilia, typically 
one or more, conspicuous in many species; extru-
somes as somatic mucocysts, sometimes of two 
types, one being rod-like; oral region, often 
expansive, with paroral often prominent with 
long cilia, forming a curtain or velum as the 
organism feeds; paroral infraciliary base with 
a short a and an elongate b segment and with 
c segment as a permanent scutica or scuti-
covestige; ribbed wall conspicuous, may be in 
two fields ; cytostome, equatorial or subequatorial 
in anterior 3/4 of body, rarely leaving room for 
a director-meridian; stomatogenesis of opisthe 
oral structures derived from paroral of proter 
and scutica ; microphagous, predominantly bacte-
rivorous, but some species algivorous; in marine, 
freshwater, and terrestrial habitats, widely distrib-
uted as free-living forms, sometimes in sands, but 
with some species commensalistic in molluscs and 
other invertebrates, and some species coprozoic; 
nine families. 
17.3 The Ciliate Taxa to Genus 419
 Family CALYPTOTRICHIDAE Small & Lynn, 
1985
 Size, small; shape, elongate ovoid; free-swim-
ming, but residing in a tubular lorica ; somatic 
ciliation, holotrichous, dense; caudal cilium, 
present; oral region occupying most of ven-
tral surface with conspicuous velum, extending 
around posterior of oral region and onto its left 
posterior margin, and with oral polykinetid 1 
relatively longer and narrower than oral polyki-
netid 2 ; cytostome, postequatorial; macronucleus, 
globular; micronucleus (?); contractile vacuole, 
present; cytoproct (?); bacterivorous; in brackish 
and freshwater habitats; one genus. 
 – Calyptotricha Phillips, 1882 
 Family CONCHOPHTHIRIDAE Kahl in Doflein 
& Reichenow, 1929 
 (syn. Conchophthiriidae ) 
 Size, small to medium; shape, generally ellipsoi-
dal to broadly reniform, laterally compressed; free-
swimming; somatic ciliation, holotrichous, dense; 
caudal cilia, may be present, sometimes long; 
thigmotactic ciliature on right anterior as field 
of structurally differentiated ciliated somatic 
dikinetids; oral region, nearly equatorial, as 
relatively small cavity into which vestibular 
kineties may extend on its right or left side; oral 
polykinetids reduced, obliquely oriented along 
left anterior wall of oral cavity; germinal row of 
stomatogenic kinetosomes deep in oral cavity ; 
macronucleus, globular to ellipsoid, rarely nodular; 
micronucleus, present; contractile vacuole, present; 
cytoproct, present; bacterivorous and detritivorous; 
in freshwater habitats as endocommensals in the 
mantle cavity (on gills) of bivalve molluscs ; two 
genera.
 – Conchophthirus Stein, 1861 
 – Conchoscutum Raabe, 1947 
 Family CTEDOCTEMATIDAE Small & Lynn, 
1985
 Size, small; shape, ovoid; free-swimming; 
somatic ciliation, holotrichous, sparse, typically 
of ciliated dikinetids; caudal cilia, prominent; oral
region, midventral with cytostome posterior to 
equator; velum of paroral segments a , b , and c , 
comb-like, as an open “C”, not extending to the 
left of the cytostome ; ribbed wall, conspicuous ; 
oral polykinetid 3 at right angle to longitudinal 
axis of oral region ; macronucleus, globular to 
ellipsoid, rarely nodular; micronucleus, present; 
contractile vacuole, present; cytoproct, present; 
bacterivorous; in marine habitats; five genera. 
 – Compsosomella Small & Lynn, 1985 
 – Ctedoctema Stokes, 1884 
 – Hippocomos Czapik & Jordan, 1977 
 – Paractedectema Small & Lynn, 1985 
 – Paractedoctema Song & Wilbert, 2000 
 Family CYCLIDIIDAE Ehrenberg, 1838 
 Size, very small to small; shape, ovoid to elongate-
ovoid, often with glabrous anterior and posterior 
zones; free-swimming; somatic ciliation, hol-
otrichous, sparse, but denser in the anterior 
half of the body in some genera; caudal cilium, 
distinctive, one to several ; oral region, not promi-
nent, with cytostome variable in position and oral 
ciliature not conspicuous; paroral dikinetid, often 
inconspicuous, typically with its postcytostomal 
curve not extending anterior and left of cyto-
stome ; oral polykinetids, often highly fragmented; 
macronucleus, globular to ellipsoid; micronucleus, 
large, often located in anterior third of body; 
contractile vacuole, present; cytoproct, present; 
bacterivorous; in marine, brackish, freshwater, and 
terrestrial habitats, widely distributed with intersti-
tial, anaerobic, and coprozoic species; ten genera. 
 – Apocyclidium Foissner, Agatha, & Berger, 2002 *
 – Caspionella Jankowski, 1980 
 – Cristigera Roux, 1899 
 – Cyclidium O.F. Müller, 1773 
 – Echinocyclidium Jankowski, 1980 
 – Isocyclidium Esteban, Finlay, & Embley, 1993 
 – Mesogymnus Berger in Corliss, 1979 [ nomen
nudum ] 
 – Paracyclidium Grolière, de Puytorac, & Grain, 
1980
 – Protocyclidium Alekperov, 1993 
 – Pseudocyclidium Small & Lynn, 1985 
 Family DRAGESCOIDAE Jankowski, 1980 
 Size, small; shape, ovoid, flattened; free-
 swimming; somatic ciliation, uneven, with 
420 17. The Ciliate Taxa Including Families and Genera
several close-set thigmotactic kineties along 
right-ventral anterolateral margin; oral region, 
midventral, with single oral polykinetid, which 
runs adjacent to the inside curve of the paroral 
and which is presumably a fusion of three oral 
polykinetids ; macronucleus, ellipsoid; micronu-
cleus, present; contractile vacuole, present; cyto-
proct, present; bacterivorous(?); in marine habitats 
as ectosymbionts on certain strongylocentrid echi-
noids ; one genus. 
 – Dragescoa Jankowski, 1974 
 Family HISTIOBALANTIIDAE de Puytorac & 
Corliss in Corliss, 1979 
 (syns. Sulciferiidae , Sulcigeridae ) 
 Size, medium to large; shape, elliptical in out-
line, with right side slightly concave and anterior 
end a little narrower than posterior; free-swim-
ming; somatic ciliation, holotrichous,