Cap 17

caudal cilia, 
forming a tuft ; oral region, small, in anterior 1/4 
of cell; oral structures as anterior extensions 
of a number of somatic kineties invaginating 
into a shallow cavity ; macronucleus, globular; 
micronucleus, present; contractile vacuole, present; 
cytoproct (?); bacterivorous; in freshwater saprobic 
habitats; one genus. 
NOTE : The oral structures of this ciliate 
need careful investigation to determine if there 
is “cryptic” tetrahymenine oral configuration. 
This family might be better placed in the Class 
 PLAGIOPYLEA . 
 – Trichospira Roux, 1899 
426 17. The Ciliate Taxa Including Families and Genera
 Order Ophryoglenida Canella, 1964 
 (syn. Ophryoglenina ) 
 Size, small to large; shape, elongate ovoid to 
spherical; somatic ciliation, holotrichous, very 
dense, with preoral suture; oral region, incon-
spicuous, with paroral and three oral polyki-
netids and its wall “supported” by the organelle 
of Lieberkühn in at least one stage in the 
life cycle ; stomatogenesis teloparakinetal, with 
de differentiation and replacement of parental 
oral structures, accompanied by marked regres-
sion of the paroral in the differentiated oral 
apparatus ; division, free-swimming or by palin-
tomy in a cyst; histophagous forms, generally feed-
ing on moribund or wounded invertebrates, though 
several species attack healthy fishes; in freshwater 
habitats; polymorphic life cycle, including resting 
cysts; two families. 
 Family ICHTHYOPHTHIRIIDAE Kent, 1881 
 (syn. Ichthyophthiridae ) 
 Size, small to large; shape, variable, with the 
Tetrahymena -like theront, elongate ovoid, and with 
the encysted tomont, spherical; free-swimming, 
but moving within the epithelial tissues in the 
parasitic phase; somatic ciliation, holotrichous, 
dense; caudal cilium, present in theront stage; oral
structures, inconspicuous, with Tetrahymena-
like microstome oral apparatus in theront and 
reduced (?) oral ciliature in trophont ; reproduc-
tion by palintomy in a cyst away from fish host, 
producing up to 2,000 tomites; macronucleus, 
globular to reniform; micronucleus, may be mul-
tiple; contractile vacuoles, may be multiple; cyto-
proct (?); feeding on cells and body fluids of hosts; 
in freshwater habitats, widespread in distribu-
tion with trophonts invading epithelial tissues 
of gills and integument of fishes, causing white 
spot disease ; two genera. 
 – Ichthyophthirioides Roque & de Puytorac, 1968 
(subj. syn. Ichthyophthirius ) 
 – Ichthyophthirius Fouquet, 1876 
 Family OPHRYOGLENIDAE Kent, 1881 
 Size, medium to large; shape, elongate ovoid; 
free-swimming; somatic ciliation, holotrichous, 
dense; caudal cilium, may be present; oral region, 
with inconspicuous opening, bordered on the 
right by conspicuous vestibular kineties and 
with oral apparatus in a deep cavity with three 
oral polykinetids, of which the posterior end of 
polykinetid 2 is enlarged, its cilia beating like a 
small brush ; reproduction by palintomy, typically 
in a cyst and producing 4–128 tomites that develop 
into small, slender theronts; macronucleus, ellip-
soid to elongate ellipsoid to ribbon-like; micronu-
cleus, may be multiple; contractile vacuole, may be 
multiple; cytoproct, present; histophagous on dying 
or dead invertebrates, but some species may be fac-
ultatively (?) parasitic, for example, in bivalve mol-
luscs ; in freshwater habitats; two genera. 
 – Ophryoglena Ehrenberg, 1831 
 – Protophryoglena Mugard, 1949 (subj. syn. 
Ophryoglena ) 
Incertae sedis in Order Hymenostomatida
 – Blepharostoma Schewiakoff, 1893 [nomen nudum] 
 – Neoichthyophthirius Bauer & Yunchis, 2001 
 Subclass Apostomatia Chatton & Lwoff, 1928 
 (syns. Apohymenida , Apostomata , Apostomea , 
 Apostomina ) 
 Size, small to medium; shape, variable during the 
polymorphic life cycle, from ovoid to very elongate; 
free-swimming; somatic ciliation, not dense, holotri-
chous in mature forms, with kineties, often spiralled 
and typically numbering <22; oral structures, highly 
modified, with a short paroral and three small oral 
polykinetids sometimes present, and an additional 
“oral or sensory (?)” structure of unknown func-
tion, the rosette, accompanied by three short kine-
ties, designated the x , y , and z kineties ; cytostome, 
variable, from broad region on cortex to inconspicuous 
or absent in certain stages; stomatogenesis, possibly 
mixokinetal, often with involvement of three or four 
specialized kinetofragments; reproduction may involve 
palintomy and catenulation; contractile vacuole, 
present; cytoproct, absent; macronucleus, homomer-
ous in trophonts, and heteromerous in tomites of many 
species; symbiotic (parasitic) in or on hosts from 
various invertebrate groups; in marine, rarely fresh-
water, habitats with only one possible terrestrial host 
– edaphic acari – reported; complex polymorphic life 
cycles, involving phoront, which is encysted on host, 
trophont, tomont, and tomite stages ; three orders. 
NOTE : The classic work of Chatton and Lwoff 
(1935a) still stands as the authoritative monograph 
17.3 The Ciliate Taxa to Genus 427
on this group. De Puytorac (1994h) subdivides this 
group up considerably, establishing many new sub-
families. In our opinion, these subdivisions need 
confirmation by molecular genetic data. 
 Order Apostomatida Chatton & Lwoff, 1928 
 (syns. Cyrtostomatina , Foettingeriida p.p ., Gem-
motomida , Gemmotomina , Incitophorina , Sang-
uicolida p.p ., Sanguicolina p.p .) 
 Size, small to medium; shape, ovoid to spheri-
cal; somatic ciliation, holotrichous, not dense, 
with x , y , and z kineties that can be associated 
with an a kinety or an a , b , and c kineties ; oral 
apparatus, as for subclass, and with rosette; tomites 
formed by multiple fission, either by palintomy 
in a cyst or by catenulation; trophonts, sangui-
colous or exuviotrophic ; in marine, occasionally 
freshwater, habitats in crustacean hosts, such as 
 hermit crabs , shrimps , and a copepod (with sea 
anemones as alternating host, for species with 
such an obligate cycle), but members of one genus 
(Phtorophrya , Family Foettingeriidae ) hyperpara-
sites of other apostomatids and an atypical family 
(Family Cyrtocaryidae ) found in polychaete anne-
lids ; three families. 
 Family COLLINIIDAE Cépède, 1910 
 (syns. Colliniida , Colliniinae ) 
 Size, small; shape, roughly pyriform with tapered 
end as posterior; free-swimming; somatic cilia-
tion, holotrichous, except for broad bare band 
medially coursing down dorsal surface ; tomite 
with nine kineties; no ogival field nor lateral canal, 
but small rosette near x kinety; macronucleus, 
ellipsoid, relatively large; micronucleus, present; 
contractile vacuole, may be in multiple rows; in
marine habitats as sanguicolous forms in the 
hemocoelomic fluid of amphipods, isopods, and
euphausiids, sometimes causing mass mortality ; 
incompletely known life cycle; two genera. 
 – Collinia Cépède, 1910 
 – Metacollinia Jankowski, 1980 
 – Paracollinia Jankowski, 1980 
 Family CYRTOCARYIDAE Corliss, 1979 
 (syn. Cyrtocaryumidae ) 
 Size of tomite very small, but trophont to 
medium size; shape of trophont, pyriform ; free-
 swimming; somatic ciliation, holotrichous, with 
up to 60 spiraled kineties in the trophont, with 
an area of strong thigmotactic cilia; caudal cil-
ium in tomites ; neither cytostome nor rosette ; 
division of trophonts in host, by unequal binary 
fission, and outside host, by catenulation; macro-
nucleus, elongated, large, partially coiled; micro-
ncleus (?); contractile vacuole, present; in marine 
habitats with tomites becoming phoronts on a
crustacean before infecting the lateral caeca of 
the digestive tract of polychaete annelids; one 
genus.
 – Cyrtocaryum Fauré-Fremiet & Mugard, 1949 
 Family FOETTINGERIIDAE Chatton, 1911 
 (syns. Foettingeriinae , Gymnodinioidae , 
 Gymnodinioinae , Gymnodinioididae , Phtorophr-