Cap 17

caudal 
cirri, may or may not be present; somatic dorsal 
ciliature as several files of bristle dikinetids, often 
showing fragmentation; adoral zone, typical of 
order, generally restricted to anterior half or quarter 
of body; division morphogenesis with six fronto-
ventral anlagen streaks in two streaks in two 
groups that make a longitudinal fan-like pat-
tern ; macronuclei, typically as two ellipsoid nod-
ules; micronucleus, present; contractile vacuole, 
at least in freshwater and terrestrial forms; cyto-
proct, dorsolateral left; feeding on bacteria, micro-
algae, and smaller protists, but several of the 
included genera are macrophagous carnivores on 
other ciliates and even smaller metazoa; in a vari-
ety of marine, freshwater, and terrestrial habitats, 
widely distributed; 42 genera and three genera 
incertae sedis . 
NOTE : This family, the most well-characterized 
among the stichotrichs , has been subdivided 
into several subfamilies (e.g., Oxytrichinae , 
 Stylonychinae ) based primarily on body flexibility 
and involvement of postoral cirrus V/3 in anlagen 
formation. The monophyly of the Subfamily 
 Stylonychinae , but not the Subfamily Oxytrichinae , 
has been confirmed by gene sequences (Foissner 
et al., 2004). Foissner and Stoeck (2006) estab-
lished the Rigidotrichidae to include Afrophrya , 
Rigidothrix , Territricha , and Uroleptus . Since these 
genera clustered among the oxytrichids based on 
gene sequences, we have tentatively placed them 
incertae sedis herein. 
 – Actinotricha Cohn, 1866 (subj. syn. Oxytricha ) 
 – Allotricha Sterki, 1878 
 – Ancystropodium Fauré-Fremiet, 1907 
 – Apoamphisiella Foissner, 1997 
 – Apourosomoida Foissner, Agatha, & Berger, 2002*
 – Architricha Gupta, Kamra, & Sapra, 2006 *
 – Australocirrus Blatterer & Foissner, 1988 
 – Coniculostomum Njiné, 1979 
 – Cyrtohymena Foissner, 1989 
 – Erimophrya Foissner, Agatha, & Berger, 2002 *
 – Gastrostyla Engelmann, 1862 
 – Gigantothrix Foissner, 1999 
 – Hemigastrostyla Song & Wilbert, 1997 
 – Hemiurosoma Foissner, Berger, & Agatha, 2002 *
 – Histriculus Corliss, 1960 
 – Laurentiella Dragesco & Njiné, 1971 
 – Neokeronopsis Warren, Fyda, & Song, 2002 *
 – Notohymena Blatterer & Foissner, 1988 
 – Onychodromopsis Stokes, 1887 
 – Onychodromus Stein, 1859 
 – Oxytricha Bory de St. Vincent in Lamouroux, 
Bory de St. Vincent & Deslongchamps, 1824 
 – Parahistriculus Grolière, 1976 (subj. syn. 
Histriculus ) 
 – Parastylonychia Dragesco, 1963 
 – Parentocirrus Voss, 1997 
 – Parurosoma von Gelei, 1954 
 – Paraurostyla Borror, 1972 
 – Pattersoniella Foissner, 1987 
 – Pleurotricha Stein, 1859 
 – Ponturostyla Jankowski, 1989 
 – Pseudostrombidium Horváth, 1933 
 – Rigidicortex Berger, 1999 
 – Rubrioxytricha Berger, 1999 
 – Steinia Diesing, 1866 
 – Sterkiella Foissner, Blatterer, Berger, & 
Kohmann, 1991 
 – Stylonychia Ehrenberg, 1830 
 – Styxophrya Foissner, Moon-van der Staay, van der 
Staay, Hackstein, Krautgartner, & Berger, 2004 *
 – Tachysoma Stokes, 1887 
 – Territricha Berger & Foissner, 1988 
 – Tetmemena Eigner, 1999 
 – Urosoma Kowalewski, 1882 
 – Urosomoida Hemberger in Foissner, 1982 
 – Vermioxytricha Foissner, Agatha, & Berger, 2002 *
Incertae sedis in Family Oxytrichidae
 – Afrophrya Foissner & Stoeck, 2006 *
 – Anatoliocirrus Özbek & Foissner in Foissner, 
Agatha, & Berger, 2002 *
 – Rigidothrix Foissner & Stoeck, 2006 *
 Family TRACHELOSTYLIDAE Small & Lynn, 
1985
 (syns. Gonostomatidae , Gonostomidae ) 
 Size, small to medium; shape, elongate and 
sometimes tailed; free-swimming; somatic ven-
tral ciliature as frontoventral cirri scattered 
on anterior near peristomal region, sometimes 
in posterior, but never on mid-area of ventral 
surface, which is bordered by right and left 
marginal cirral files ; transverse cirri, present or 
absent; caudal cirri, present or absent; somatic 
dorsal ciliature as several files of bristle dikinetids; 
oral ciliature as for order with paroral and endoral, 
but in some genera the adoral zone of oral poly-
17.3 The Ciliate Taxa to Genus 361
kinetids is divided into an anterior and posterior 
part; macronucleus, two to many ellipsoid nodules; 
micronuclei, several; contractile vacuole, present at 
least in freshwater forms; cytoproct, likely present; 
feeding on bacteria, algae, and smaller protists; in 
marine, freshwater, and terrestrial habitats; seven 
genera.
 – Cossothigma Jankowski, 1978 
 – Gonostomum Sterki, 1878 
 – Hemisincirra Hemberger, 1985 
 – Paragonostomum Foissner, Agatha, & Berger, 
2002*
 – Spirotrachelostyla Gong, Song, Li, Shao, & 
Chen, 2006 *
 – Terricirra Berger & Foissner, 1989 
 – Trachelostyla Borror, 1972 
Incertae sedis in Order Sporadotrichida 
 – Cinetoconia Renault & Roche, 1898 [ nomen
dubium ] 
 – Etoschothrix Foissner, Agatha, & Berger, 2002 *
 – Gruberella Corliss, 1960 
 Order Urostylida Jankowski, 1979 
 (syns. Pseudokeronopsina p.p ., Urostylina ) 
 Size, small to large, up to 800 µm; shape, elongate-
elliptical in outline, sometimes quite broad; free-
swimming; somatic ventral ciliature as frontov-
entral cirri in zig-zag files, running almost the 
full length of ventral surface between right and 
left files of marginal cirri and ranging from a 
“single” file of zig-zag or offset cirri to multi-
ple and short files of cirri whose anterior and 
sometimes posterior ends are offset (= devel-
oped zig-zag) (e.g., Eschaneustyla ) ; transverse 
cirri, present or absent; caudal cirri, present or 
absent; somatic dorsal ciliature as three or more 
kineties of bristle dikinetids; during division 
morphogenesis, zig-zag cirri differentiating 
from anlagen of many short oblique kineto-
fragments ; four families. 
 Family EPICLINTIDAE Wicklow & Borror, 1990 
 Size, medium to large; shape, very flexible, elon-
gate with distinct, elongate tail; free- swimming; 
somatic ventral ciliature as many oblique files 
of ventral cirri, arising by elineation from five 
to seven anlagen ; marginal cirral files, present; 
transverse cirri as prominent oblique file, par-
allel to left marginal file ; caudal cirri, present; 
dorsal somatic ciliature, several files of diki-
netids; oral structures as for order; macronucleus, 
several to many nodules; micronucleus, present; 
contractile vacuole, present; cytoproct (?); feed-
ing on bacteria and diatoms; in marine habitats; 
two genera. 
 – Epiclintes Stein, 1863 
 – Eschaneustyla Stokes, 1886 
 Family PSEUDOKERONOPSIDAE Borror & 
Wicklow, 1983 
 (syns. Pseudokeronopsinae , Thigmokeronopsinae ) 
 Size, medium to large; shape, elongate; free-
swimming; somatic ventral ciliature as frontal 
cirri forming a conspicuous, arc-like file that 
parallels the anterior left serial oral polyki-
netids, which may be doubled by an arc-like 
extension of the frontoventral zig-zag file; left 
and right marginal cirri as 1 (rarely 2) file(s) ; 
transverse cirri, present or absent; caudal cirri, 
present or absent; dorsal somatic ciliature as three 
or more files of bristle dikinetids; oral ciliature as 
for order with paroral and endoral; macronucleus, 
ellipsoid, typically many more than two; micro-
nucleus, present; contractile vacuole, present at 
least in freshwater forms; cytoproct, likely present; 
feeding on bacteria, algae, and smaller protists; in 
marine, freshwater, and terrestrial habitats; three 
genera and three genera incertae sedis . 
 – Pseudokeronopsis Borror & Wicklow, 1983 
 – Thigmokeronopsis Wicklow, 1981 
 – Uroleptopsis Kahl, 1932 
Incertae sedis in the Family Pseudokeronopsidae 
 – Bicoronella Foissner, 1995 
 – Keronella Wiackowski, 1985 
 – Tricoronella Blatterer & Foissner, 1988 
 Family PSEUDOUROSTYLIDAE Jankowski, 
1979
 (syn. Pseudourostyloidea) 
 Size, medium to large; shape, elongate ovoid; 
free-swimming; somatic ventral ciliature as fron-
tal cirri forming a conspicuous,