round or elliptical; macronucleus, globular to elon- gate ellipsoid; micronucleus, present; contractile vacuole (?); cytoproct (?); feeding on various heter- otrophic protists; in freshwater and terrestrial habi- tats; three genera and one genus incertae sedis . – Ovalorhabdos Foissner, 1984 – Paraenchelys Foissner, 1983 – Pseudoholophrya Berger, Foissner, & Adam, 1984 Incertae sedis in Family Pseudoholophryidae – Songophrya Foissner, 2003 * Family PSEUDOTRACHELOCERCIDAE Song, 1990 Size, medium; shape, cylindrical or bottle- shaped; free-swimming; somatic ciliation, hol- otrichous, having bipolar kineties with anterior kinetids more densely packed; kinetids of brosse kinety irregularly arranged and continuous with only one somatic kinety ; extrusomes as oral toxicysts; oral region, apical; macronucleus, elon- gate band; micronucleus (?); contractile vacuole, present; cytoproct (?); feeding possibly on bacteria; in marine habitats; one genus. – Pseudotrachelocerca Song, 1990 Family SPATHIDIIDAE Kahl in Doflein & Reichenow, 1929 (syns. Arcuospathidiidae , Bryophyllidae , Myriokaryonidae , Paraspathi diidae , Perispiri- dae , Protospathidiidae , Spathidiina p.p ., Teutho- phryidae ) 370 17. The Ciliate Taxa Including Families and Genera Size, small to very large; shape, ovoid to elon- gate, often flask- or sack-shaped, flattened, with obliquely truncate anterior end; free-swimming; somatic ciliation, holotrichous; brosse kineties, 2–4; extrusomes as somatic mucocysts and sev- eral types of oral toxicysts; oral region, anterior, flattened, usually elongate dorsoventrally (except Protospathidium ) with slit-like cytostome, gener- ally located apically on non-ciliated ridge of body, facilitating ingestion of large prey; circumoral dikinetids as proliferated anterior fragments of somatic kineties, which may exceed the number of somatic kineties, and which may remain as separated groups after stomatogenesis ; macro- nucleus, extremely variable, from single ellipsoid, to multiple, to ribbon-like and moniliform; micro- nucleus, present; contractile vacuole, present; cyto- proct (?); feeding on flagellates and other ciliates; in marine, freshwater, and terrestrial habitats; 29 genera and three genera incertae sedis . NOTE : Foissner, Berger, and Schaumburg (1999) redescribed Teuthophrys and suggested that it was related to the spathidiids based on its infraciliary pattern and extrusomes, and this was confirmed by Strüder-Kypke et al. (2006) using its small subunit rRNA gene sequence. Foissner (2003) established the Family Myriokaryonidae to include the genera Myriokaryon , Bergophrya , Cephalospatula , and Kahlophrya , but admitted that this family was difficult to separate from the Family Spathidiidae . Until gene sequence data demonstrate its monophyly, we have retained these genera in the Family Spathidiidae . – Apobryophyllum Foissner, 1998 – Arcuospathidium Foissner, 1984 – Armatospathula Foissner & Xu, 2006 * – Bergophrya Foissner, 2003 * – Bryophyllum Kahl, 1931 – Cephalospatula Foissner, 2003 * – Cranotheridium Schewiakoff, 1893 – Cultellothrix Foissner, 2003 * – Diceratula Corliss, 1960 (subj. syn. Spathidium ) – Edaphospathula Foissner & Xu, 2006 * – Epispathidium Foissner, 1984 – Kahlophrya Foissner, 2003 * – Lacerus Jankowski, 1967 – Latispathidium Foissner, Berger, & Zechmeister- Boltenstern, 2005 – Micromidas Delphy, 1938 – Myriokaryon Jankowski, 1973 – Neobryophyllum Foissner in Foissner & Lei, 2004* – Paraspathidium Noland, 1937 – Penardiella Kahl, 1930 – Perispira Stein, 1859 – Protospathidium Dragesco & Dragesco-Kernéis in Foissner, 1984 – Semispathidium Foissner, Agatha, & Berger, 2002* – Spathidiodes Kahl, 1926 – Spathidioides Brodsky, 1925 – Spathidiosus Gajewskaja, 1933 – Spathidium Dujardin, 1841 – Supraspathidium Foissner & Didier, 1982 – Teuthophrys Chatton & de Beauchamp, 1923 – Thysanomorpha Jankowski, 1967 Incertae sedis in Family Spathidiidae – Apospathidium Foissner, Agatha, & Berger, 2002* – Enchelaria Foissner, Agatha & Berger, 2002 * – Proboscidium Meunier, 1910 Family TRACHELIIDAE Ehrenberg, 1838 (syns. Branchioecetidae , Dileptidae , Dileptina ) Size, medium to large; shape, flask-shaped with dorsal proboscis of varying relative length ; free-swimming; somatic ciliation, holot- richous; extrusomes as somatic mucocysts and several types of oral toxicysts; brosse kineties, three or more; oral region, circular or elliptical, possibly with permanent cytostome, distant from extreme anterior end of body at base of proboscis, but with oral kinetids extending along the borders of the ventral surface of the proboscis and with toxicysts in this ventral band or distributed around the cytostome ; oral nematodesmata, lengthy, prominent, supporting the cytopharynx, typically in two rings, the outer one associated with the circumoral dikinetids; macronucleus, very variable in shape, from single globular to band-shaped to multiple globular and even moniliform; micronucleus, present, may be multiple; contractile vacuole, at least present in freshwater forms; cytoproct (?); feeding on flagellates, microalgae, and other ciliates; in marine, freshwater, and terrestrial habitats, with some forms planktonic; ten genera and one genus incertae sedis . 17.3 The Ciliate Taxa to Genus 371 – Branchioecetes Kahl, 1931 – Dileptus Dujardin, 1841 – Dimacrocaryon Jankowski, 1967 – Micruncus Delphy, 1938 – Monilicaryon Jankowski, 1967 – Paradileptus Wenrich, 1929 – Pelagodileptus Foissner, Berger, & Schaumberg, 1999 – Pseudomonilicaryon Foissner, 1997 – Rimaleptus Foissner, 1984 – Trachelius Schrank, 1803 Incertae sedis in Family Tracheliidae – Ctenoctophrys Weill, 1946 [not listed in Aescht] Family TRACHELOPHYLLIDAE Kent, 1882 (syns. Enchelyodontidae p.p ., Lagynophryidae , Trachelophyllina p.p .) Size, small to medium, rarely large; shape, long-ovoid or flask-shaped, slightly flattened; free- swimming; somatic ciliation, holotrichous; brosse kineties, two to many in Acaryophrya ; extrusomes as somatic mucocysts and lepidosomes (e.g., in Lepidotrachelophyllum and Spetazoon ) and some- times several types of oral toxicysts; oral region circular to elliptical, sometimes forming an obvi- ously pointed dome; circumoral dikinetids typi- cally at anterior end of bipolar somatic kineties, not exceeding the number of somatic kineties (except some Enchelyodon species) ; macronu- cleus, quite variable, from single ellipsoid to paired ellipsoid to band-form or multiple and moniliform; micronucleus, present; contractile vacuole, present; cytoproct, present; feeding on flagellates and other ciliates, even rotifers in large forms; in marine, freshwater, and terrestrial habitats; 12 genera. NOTE : The synapomorphy for this family is not a strong one, but subdivision on characters such as the lepidosomes (see Foissner et al., 2002) seems premature at this time. – Acaryophrya André, 1915 – Bilamellophrya Foissner, Agatha, & Berger, 2002* – Enchelyodon Claparède & Lachmann, 1859 – Enchelyotricha Foissner, 1987 – Epitholiolus Foissner, Agatha, & Berger, 2002 * – Foissnerides Song & Wilbert, 1989 – Lagynophrya Kahl, 1927 – Lepidotrachelophyllum Nicholls & Lynn, 1984 – Luporinophrys Foissner, 2005 * – Sleighophrys Foissner, 2005 * – Spetazoon Foissner, 1994 – Trachelophyllum Claparède & Lachmann, 1859 Order Pleurostomatida Schewiakoff, 1896 (syns. Amphileptida p.p ., Amphileptina p.p ., Litonotina p.p ., Pleurostomata , Pleurostom[at]ina , Scaphotrichina , Thysanophorina ) Size, medium to large; shape, leaf-like or later- ally compressed, sometimes with lengthy, attenu- ated