Historical backgroud to the establishment of the phylum Opalozoa
The phylum Opalozoa subsumes the earlier phylum Proterozoa Cavalier-Smith 1981, which was founded to contain proteromonads opalinids, and a large number of tubulicristate taxa, such as cyathobodonids that were omitted from the revised protozoan classification (Levine et al. 1980). Proterozoa becomes a subphylum of Opalozoa. I originally defined Opalozoa as tubulicristate zooflagellates without cortical alveoli or an apical complex (Cavalier-Smith, 1991). Since this definition embraces the recently discovered Hemimastix (Foissner et al. 1988), I include it in Opalozoa rather than as a separate phylum. I also include Plasmodiophorida in the Opalozoa since their zoospores are similar to certain opalozoan flagellates; their minute plasmodia are insufficient justification for placing the order in either Rhizopoda or Mycetozoa. It is relatively simple for a zooflagellate to evolve a plasmodial phase by developmental delays of cytokinesis and of ciliary and ciliary root growth; this has undoubtedly occurred several times in protozoan evolution (another example within Opalozoa is the zooflagellate Thaumatomonas (Karpov and Zhukov 1987, Shirkina and Selivanova 1982), so it is insufficient basis for the phylum-level separations or for grouping other protozoa that otherwise are very different. Originally I placed Jakoba libera in the Choanozoa on account of its flat cristae. The recent discovery of Reclinomonas, a flagellate similar to Jakoba but with tubular cristae (O'Kelly 1993) made it necessary to reconsider the characteristics used to differentiate Opalozoa and Choanozoa. I therefore transfer Jakoba to the Opalozoa and slightly widen the phylum definition to include not only Jakoba libera but also Ancyromonas (Mylnikov 1990, Patterson and Zolffel 1991) despite their flattish cristae. As a result all Choanozoa are now choanoflagellates.
Diagnoses of the phylum Opalozoa and its four subphylum
Phylum 1: Opalozoa Cavalier-Smith, 1991 Mitochondrial cristae typically tubular (if flattened [rarely: sole known examples Jakoba libera and Ancyromonas] then kinetid anisokont with 2 cilia, 3 asymmetric microtubular roots and lacking a periciliary collar, and lacking cryptomonad-type double-scroll ejectisomes [this latter proviso is necessary to exclude the cryptist Goniomonas]); tubular cristae vary in form from bleb-like to elongated (occasionally branched) tubes, but lack the intracristal filament found in chromobiotes and some Dinozoa; mitochondrial DNA not organized as a kinetoplast; plastids absent; peroxisomes usually present; well developed Golgi dictyosomes cortical alveoli and aerial spore-bearing fruiting bodies absent; cell was, if present (rarely in trophic stage), chitinous not cellulosic; having a single kinetid of 1, 2, or 4 (usually 2) cilia or (rarely) many cilia in rows; tubular ciliary hairs absent; extrusomes often present; uninucleate, or multinucleate with equivalent non-heterokaryotic nuclei; mostly unicellular flagellates, rarely multiciliated or occasionally meroplasmodia or plantparasitic microplasmodia with biciliate swarmers.
Subphylum 1: Proterozoa Cavalier-Smith 1981 n.stat.emend. Usually free-living uninucleate non-loricate flagellates (rarely microplasmodial parasites or meroplasmodia with a biciliate stage) with 2 (rarely 1 [sole example Phalansterium]) cilia; axopodia absent; cell surface (unlike in Opalinata) not extended as narrow folds supported by a vertical row of microtubules, nor with cortical ridges and plates of euglenoid type. Nucleus of ciliated stages closely associated with the centrioles (probably attached by amorphous material) or attached to them by a compound microtubular rhizoplast. Extrusomes, when present, dense globules, elongate tubes, single scrolls, or a "Stachel" penetration apparatus; never kinetocysts. Peroxisomes usually present; mitochondrial cristae tubular (usually unbranched), or rarely irregularly flattened, but not discoid.
Subphylum 2: Opalinata Wenyon 1926 emend. Uninucleate non-loricate flagellates with 4 cilia or uni- or multinucleate cells with many rows of monokinetid cilia that are divided longitudinally; cell surface extended into narrow folds, each supported by a vertical row of interlinked microtubules; parasites or commensals of the gut of terrestrial vertebrates; nucleus not closely associated with the centrioles; extrusomes absent peroxisomes probably absent; mitochondrial cristae tubular, unbranched.
Subphylum 3: Kinetomonada n.subph. Free-living uninucleate flagellates with 2 (anisokont and heterodynamic) or 4 cilia; extrusomes are kinetocysts with cylindrical substructure; loricate or with a thick surface coat or with axopodia containing an axoneme of microtubules nucleated by an axoplast associated with the exceptionally long ciliary centrioles; mitochondrial cristae branched tubules or flattish; peroxisomes present.
Subphylum 4: Hemimastigophora Foissner, Blatterer & Foissner 1988 n.stat. Uninucleate cell with two-fold rotational symmetry having a plicate pellicle with two large pellicular plates, a distinct epiplasm and subpellicular microtubules; 2 rows of identical cilia in the grooves between the plates; temporary cytostome at anterior pole; nucleus not obviously associted with or attached to the centrioles; complex extrusomes shaped like a wine bottle with a nail-like compartment embedded in the neck; centrioles exceptionally short; ciliary transitional plate and a very slender transitional helix; tubular mitochondrial cristae occasionally connecting to a caverna.
Classification of the phylum Opalozoa and its eight classes
The Phylum Opalozoa is here divided into eight classes of which five are new and one (Opalinea) is emended. Hemimastix being unique in having a pellicle with similarities to that of euglenoids, and numerous cilia, is in a class of its own, Hemimastigea Foissner, Blatterer & Foissner, 1988, and also in its own new subphylum: Hemimastigophora Foissner, Blatterer & Foissner n.stat. The flagellate Karotomorpha and Opalinida are clearly more closely related to each other than to any other Protozoa, since they uniquely possess cortical ridges strengthened by microtubule bands, as Brugerolle & Joyon 1975 and Patterson 1985 stressed; therefore Karotomorpha is here removed from the Proteromonadida and placed in the class Opalinea as the sister group of the Opalinida within the subphylum Opalinata (opalinids do not deserve phylum status (Corliss 1984). Histiona, Dimorpha and Tetradimorpha are unique among Opalozoa in having kinetocysts (Brugerolle & Mignot 1984), like many Actinopoda, and are therefore placed in their own new class Kinetomonadea and new Subphylum Kinetomonada.
Other Opalozoa: subphylum Proterozoa: All the remaining Opalozoa lack axopodia, the euglenoid type of pellicle and the opalinean cortical ridges, and are therefore placed in the new subphylum Proterozoa, which is divided into five classes according to their kinetid type and the presence or absence of silicious skeletons or endoparasitic microplasmodia. The Ebridea are treated as a distinct class because of their unique silicious skeleton of soild rods. The name Ebriophyceae Loeblich III, 1970 is entirely inappropriate for a class of non-photosynthetic protozoa. On account of their endoparasitic microplasmodia the Plasmodiophorida are grouped with Phagomyxa (Karling 1944) in the class Phytomyxea, which is placed in the Proterozoa on the basis of their zoospore structure, which is quite similar to that of cercomonads. Proterozoa which have neither a silica skeleton nor endoparasitic microplasmodia have not previously been assigned to classes; they are here divided into three classes according to their kinetid type. Those with an isokont kinetid of 2 anterior cilia (or possessing only a single, anterior, cilium) are grouped in the new class Cyathobodonea (in three orders: Pseudodendromonadida Hibberd, Spongomonadida Hibberd (incl. Phalansteriida Hibberd), and Kathablepharida ord. nov. here created for Kathablepharis (Lee & Kugrens 1991, Lee et al. 1991) and Leucocryptos; those with an isokont kinetid of two posterior cilia are placed in the new class Telonemea (currently containing only Telonema (Hollande & Cachon 1950), for which a new order Telonemida is created here, and Nephromyces (Saffo 1981, 1991) for which a new order Nephromycida is created here); those with an anisokont kinetid are placed in the new class Heteromitea. The nine heteromitean orders are further grouped into three subclasses: 1) the Sarcomonadida for those that are non-thecate and have isodiametric extrusomes, 2) the Thecomonadea for the two thecate orders with elongated extrusomes, and 3) Anisomonadia for those with neither theca nor extrusomes but with a complete or nearly complete investment of pellicular microtubules. The five sarcomonad orders are grouped into three new superorders: Jakobidea characterised by a single Golgi dictyosome (orders Jakobida and Cercomonadida); Thaumatomonadidea characterised by scales made in vesicles associated with the mitochondria (sole order Thaumatomonadida); and Proteomyxidea characterised by an unusual intranuclear rod of microfilaments, not seen in other protists (orders Pseudosporida and Leucodictyida).
Subphylum 1. PROTEROZOA Cavalier-Smith 1981 n.stat.emend.
Class 1. Heteromitea n.cl.
Flagellates with a single biciliate and anisokont kinetid (1 cilium directed forwards, one backwards; or rarely with 2 forward-pointing cilia with divergent centrioles); paraxial rods absent; extrusomes, if present, never of the scroll (ejectisome) type; distinct cytostome/cytopharynx absent, but a ventral or lateral groove is commonly involved in ingestion; lacking a silicious skeleton of solid rods; nucleus usually attached of the centrioles by amorphous material or by microtubules; mitochondiral cristae tubular or (very rarely) flat (but not discoid); lacking a parasitic intracellular microplasmodial phase; lacking long surface folds supported by a row of microtubules.
Subclass 1. Sarcomonadia n.subcl.
Theca absent; extrusomes isodiametric; transitional helix and paraxial rods absent; cilia with an axosome and a single transitional plate; pseudopodia often presense dictyosomes associated with the nuclear, with the cisternae parallel to the nuclear envelope and receiving vesicles directly from its outer membrane.
Superorder 1. Jakobidea n.superord.
Flagellates with no pseudopodia or with transient lobose pseudopods from the anterior or the posterior end of the cell; scales sparse or absent; pellicular microtubules rare or cover only part of the cell surface; nuclei without an internal dense fibrous rod.
Order 1 Jakobida n.ord.
Pseudopodia absent; rear cilium with a flange supported by dense paraxial material; mitochondrial cristae irregularly flattened.
Jakobidae Patterson 1990. Diagnosis as for order Jakobida. Type and sole genus Jakoba Patterson 1990.
Order 2. Cercomonadida Poche 1913 emend. Vickerman in Honigberg, 1983
Anisokont phagotrophic biflagellates with 1 anterior and 1 trailing cilium; cilia non-flanged. The single Golgi dictyosome is associated with the nucleus alongside one of the basal bodies (centrioles), and receives vesicles directly from the outer membrane of the nuclear envelope. A peroxisome-like microbody is attached to the nuclear envelope. A peroxisome-like microbody is attached to the nuclear envelope on the opposite side from the centrioles and dictyosome. Mitochondrial cristae tubular. Extrusomes, when present are isodiametric dense bodies. Except for the 3 microtubular ciliary roots, the cell cortex has very few, if any, microtubules over most of its surface and in most species forms pseudopods for feeding. Ciliary transitional plate present; transitional helix absent. A distinct cytostome or cytopharynx is absent. Cysts frequent.
Family 1. Cercomonadidae Kent 1880/1 emend. Pseudopodia lobose and unbranched, and lack microtubules. Velum absent. (Cercomonas Dujardin 1841, Heteromita Dujardin 1841.)
Family 2. Massisteridae n.fam. Trophic phase with long radiating branching pseudopodia containing microtubules and extrusomes. Velum absent. Type and sole genus Massisteria Patterson and Fenchel 1990.
Family 3. Discocelidae n.fam. Flattened cells lacking pseudopods but with a velum supported by 1 microtubule at its anterior rim and 2 microtubules (probably a modified ciliary root) at its posterior rim. Sole and type genus Discocelis Vors 1988.
Superorder 2. Thaumatomonadidea n.superord.
Scale-covered phagotrophic biciliates; usually with a ventral groove from which pseudopodia emerge during feeding; scales are formed in vesicles attached to the mitochondria; transitional helix and paraxial rods absent; several Golgi dictyosomes per cell, associated with the nucleus; nuclei lacking an internal dense fibrous rod.
Order Thaumatomonadida Shirkina 1987.
Family 1. Thaumatomonadidae Hollande 1952. Thaumatomonas de Saedeleer 1931, Gyromitus Skuja 1939, Hyaloselene Skuja 1956, Synoikomonas Skuja 1969, Thaumatomastix Lauterborn 1899 (syn. Thaumatonema Lauterborn 1899; includes Reckertia Conrad 1920).
Family 2. Protaspidae Skuja 1939 orthog.emend. (orig. Protaspidaceae) Protaspis Skuja 1939 (electron microscopy is needed to test its assignment to this order); possibly Rhizaspis Skuja 1948 belongs here.
Superorder 3. Proteomyxidea Lankester 1885 n.stat. Delage & Herouard 1896 emend. (originally a class with much more heterogeneous contents)
Scales absent; non-transient filose or reticulose pseudopods present in trophic phase; nuclei with an internal dense rod composed of parallel microfilaments; several dictyosomes per nucleus; rather irregular, broadly tubular mitochondrial cristae. (How many of the Proteomyxids (Valkanov 1940) really belong here will not be known until they have been studied by electron microscopy)
Order 1. Pseudosporida n.ord.
Amoeboflagellates that feed on algae; pseudopods filose, non-anastomosing; cilia present or absent in trophic phase; extrusomes are mucocysts with relatively amorphous contents.
Family Pseudosporidae Berlese in Saccardo 1888. Pesudosporea Cienkowski 1865.
Order 2. Leucodictyida n.ord.
Cell bodies of the trophic phase enclosed in loosely fitting loricae, and form reticulopodia that fuse with those of other cells to form an extensive multicellular network (a meroplasmodium (Grell 1991)); trophic phase non-ciliated; extrusome contents multilayered and asymmetric.
Family Leucodictyidae n.fam. Diagnosis as for order Leucodictyida. Sole and type genus Leucodictyon Grell 1991.
Subclass 2. Thecomonadia subcl.nov.
Dense theca closely surrounding the cells, firmly attached to part or most of the plasma membrane; feeding pseudopods, often branching, emanate from a ventral or two ventrolateral grooves where the theca is not closely attached to the plasm membrane. Cilia with or without a transitional helix, ciliary paraxial rod absent. Scales absent. Extrusomes highly elongated.
Order 1. Apusomonadida Karpov & Mylnikov 1989.
Anisokont phagotrophic biflagellates with the posterior cilium in a cytopharyngeal groove that is supported by the 3 microtubule bands of the ciliary roots. Long extrusomes present. Transitional helix and paraxial rods absent. Dictyosome and microbody not generally associated with the nucleus.
Family Apusomonadidae Karpov & Mylnikov 1989. (Apusomonas Alexieff 1924 [incl. Rostromonas Karpov & Zhukov 1980], Amastigomonas de Saedeleer 1931 includes Thecamonas Larsen & Patterson 1990.)
Order Cryomonadida n.ord.
Flagellates with 2 anterior cilia protruding from a multilayered theca and a lateral cytostome from which pseudopodial activity can take place; ciliary paraxial rods absent; ciliary transition zone with transitional helix; long extrusomes present.
Family Cryothecomonadidae n.fam. Diagnosis as for the order Cryomonadida. Sole and type genus: Cryothecomonas Thomsen, Buck, Bolt & Garrison, 1991.
Subclass 3. Anisomonadia n.subcl.
Theca and extrusomes absent; pellicular microtubules underlie all or most of the plasm membrane; ciliary transition helix or a ciliary transition sheath present; pseudopodia absent.
Order 1. Diphylleida n.ord.
Non-thecate flagellates with 2 anterior subequal cilia and a ventral groove for phagotrophy; ciliary parallel rods and somatonemes absent; ciliary transition zone with dense granule (axosome); transitional helix absent, though there is a dense sheath around the base of the ciliary central pair; microtubular roots, of which 2 are attached to the ventral ciliary basal body and support the two lips of the ventral groove, while the third (attached to the dorsal cilium) is the nucleating centre for a cape of pellicular microtubules that support the rest of the cell.
Family Diphylleidae n.fam. Diagnosis as for order. Sole and type genus Diphyllea Massart 1920 (syn. Aulacomonas Skuja 1939).
Order 2. Proteromonadida Grasse 1952 emend.
Anisokont flagellates with 2 cilia; a paraximal rod in the anterior cilium only. Regularly arranged longitudinal subpellicular microtubules with rigid bipartite tubular of cell surface hairs (somatonemes) attached to them through the plasm membrane. Microtubules from both centrioles converge to form a rhizostyle that passes through an invagination in the nuclear envelope and attaches to the single large mitochondrion on the other side; ciliary transitional helix. Gut symbionts of amniotes, which lack a cytostome or pseudopods and probably do not ingest bacteria. Peroxisomes absent. Form cysts.
Family Proteromonadidae Grasse 1952. Diagnosis as for order Proteromonadida. Sole genus Proteromonas Kunstler 1889.
Class 2. Phytomyxea Engler & Prantl 1897 orthog.emend. (orig. Phytomyxinae).
Life cycle alternates between plant-parasitic microplasmodia and anisokont biciliated zoospores (1 anterior and 1 posterior cilium) produced in a chitin-walled sporangium; ciliary paraxial rods absent; centrioles very long.
Order 1. Phagomyxida ord.nov.
Resting spores and cytosori unknown; plasmodium strongly phagotrophic; parasites of algae.
Family Phagomyxidae n.fam. Diagnosis as for order Phagomyxida. Sole and type genus Phagomyxa Karling 1944.
Order 2. Plasmodiophorida Cook, 1928
Resting spores present, usually grouped in a cystosorus; plasmodium non-phagotrophic or possibly rarely weakly phagotrophic; parasites of algae, fungi, oomycetes or vascular plants; extrusome a complex "Stachel" used for penetrating host cells.
Family Plasmodiophoridae Zopf 1884 orthog.emend. (Dylewski 1990) Nine genera: Plasmodiophora Woronichin 1877, Tetramyxa Goebel 1884, Octomyxa Couch, Leitner & Whiffen 1939; Sorodiscus Largeb. & Winge 1913; Sorosphaera Schroter 1866, Spongospora Brunch 1887, Ligniera Maire & Tison 1911, Woronina Corvu 1872, Polymyxa Ledingham 1939.
Class 3. Telonema n.cl.
Free-living or symbiotic flagellates with 2 posterior cilia; mitochondrial cristae tubular; cytopharynx absent.
Order 1. Telonemida n.ord.
Free-living flagellates with 2 similar posterior flagella. Walled filamentous stages absent.
Family Telonemidae n.fam. Diagnosis as for order. Type and sole genus Telonemea Griessmann 1913.
Order 2. Nephromycida n.ord.
Symbionts of tunicates with complex life cycles including chitin-walled (Saffo & Fultz 1986) filaments and a ciliated stage with 2 posterior cilia.
Family Nephromycidae fam.nov. Diagnosis as for order. Sole and type genus Nephromyces Giard 1888.
Class 4. Cyathobodonea n.cl.
Free-living biflagellates with 2 isokont anteriorly pointing cilia with parallel centrioles or (rarley) with a single cilium and centriole; paraxial rods absent; cytopharynx, if present, at one end of flat anterior edge of cell away from the cilia; mitochondrial cristae tubular; extrusomes, when present, of the scroll (ejectisome) type, but unlike those of cryptomonads and Goniomonas (but like those of prasinophytes) they lack the small subsidiary scroll at the distal end.
Order 1. Pseudodendromonadida Hibberd 1985.
Roughly triangular or basin-shaped phagotrophic cells with 2 subequal heterodynamic cilia inserted into a small papilla at one edge of the flat end; cytostome present at opposite edge of the flat end; cytopharynx encircled by a band of ciliary root microtubules; sessile stalked or free swimming cells; extrusomes absent; cell body covered with non-mineralized Golgi-produced scales; cilia scaly.
Family Pseudodendromonadidae n.fam. Diagnosis as for order. Pseudodendromonas Bourelly 1953, Cyathobodo Petersen & Hansen 1961.
Order 2. Spongomonadida Hibberd 1983 emend. Karpov 1990 (i.e. incl. Phalansteriida Hibberd 1983).
Colonial phagotrophic cells with 1 or 2 anterior cilia, but no cytostome/cytopharynx or scales; extrusomes absent.
Family Spongomonadidae Karpov 1990. Two cilia. (Spongomonas Stein 1878, Rhipidodendron Stein 1878).
Family Phalansteriidae Kent 1880 emend. Karpov 1990. One cilium and centriole. Phalansterium Ciencowsky 1870.
Order 3. Kathablepharida ord.nov.
Flagellates with 2 subequal anterior cilia; scrolled ejectisomes and a striated thickening of the cell surface that extends over the cell body as well as the cilia; cytopharynx absent; cytostome at anterior end of cell, subtended by 4 microtubule bands.
Family Kathablepharidae Stein 1939. Type genus Kathablepharis Skuja 1939; (Leucocryptos Butcher 1967).
Class Ebridea Lemmermann 1901 emend. Deflandre 1936 n.stat. Loeblich III 1970 orthog. emend.
Order Ebriida Deflandre 1936
Phagotrophic flagellates with 2 cilia and an internal solid silicious skeleton composed of a 3- or 4-rayed spicule. Narrow tubular cristae (H. A. Thomsen, pers. commun.).
Family 1 Hermesinidae Hovasse 1943 Hermesinum Zacharias 1906, Hermesinella Deflandre 1934 plus about 12 extinct genera.
Family 2 Ditripodiidae Deflandre 1951 (four extinct genera).
Family 3. Ammodochiidae Deflandre 1950 (two extinct genera).
Family 4. Ebriidae Lemmermann 1901 orthog.em. Poche 1913 Ebria Borgert 1891, Ebrinula Deflandre 1950 (extinct).
Subphylum 2: OPALINATA Wenyon 1926 emend.
Class Opalinea Wenyon 1926 emend.
Four to many identical cilia, lackig paraxial rods. Cell surface arranged as numerous narrow folds in which the plasma membrane is supported by a broad ribbon of laterally attached microtubules. Gut parasites of fish or amphibians which lack phagocytosis and absorb food by micropinocytosis. Peroxisomes absent. Cysts common. A double ciliary transition-region helix present.
Order 1. Karotomorphida n.ord.
One nucleus and 4 cilia only; cysts and sex unknown.
Family Karotomorphidae Grasse 1952. Karotomorpha Travis 1934 (syn. Tetramastix Alexeiff).
Order 2. Opalinida Poche 1913 stat.nov. Hall 1953
Many rows of cilia; 1, 2, four or many nuclei; cysts usual; sex with prezygotic meiosis.
Family Opalinidae Claus 1874. Hegneriella Earl 1971, Protoopalina Metcalf 1918, Zelleriella Metcalf 1923, Cepedea Metcalf 1923, Opalina Purkinje & Valentin 1835.
Subphylum 3: KINETOMONADA n.subphy.
Class Kinetomonadea n.cl.
Diagnosis as for subphylum Kinetomonada.
Order 1. Histionida n.ord.
Loricate or aloricate flagellates without axopodia; cristae flat or tubular; 3 asymmetric ciliary microtubular roots.
Family 1. Ancyromonadidae n.fam. Aloricate flagellates with a thick surface coat; mitochondrial cristae flat. Type genus Ancyromonas Kent 1880 (Mylnikov 1990 where incorrectly referred to as a Hetromita sp., (Patterson & Zolffel 1991)
Family 2. Histionidae n.fam. Loricate flagellates with both cilia protruding from the lorica. Mitochondrial cristae tubular. Type genus Histiona Voigt 1902 (since Histiona apparently lacks tubular ciliary hairs it is not a bicosoecid (Mylnikov 1989); Reclinomonas Flavin & Nerad 1993.
Order 2. Heliomonadida n.ord.
Non-loricate flagellates with axopodia in trophic phase; cristae branched tubules.
Family Dimorphyidae Febvre-Chevalier & Febvre 1984. Two cilia; axoplast surrounded by the nucleus; axopodial axonemes with microtubules in an overlapping square array (quincunx pattern) and pass through cytoplasm tunnels transversing the nucleus. Dimorpha Gruber 1881. The name Dimorpha may need to be changed; since the genus was preoccupied by Dimorpha Jurine 1807, a genus of hymenopteran insects, Dimorpha Gray 1840, a genus of molluscs, and Dimorpha Hodgson 1841, a genus of birds.
Family Tetradimorphyidae Febvre-Chevalier & Febvre 1984. Four cilia; axopodia axonemes with an irregular array of microtubules, passing near to but not through the nucleus. Tetradimorpha Hsiung 1927.
Subphylum 4: HEMIMASTIGOPHORA Foissner, Blatterer & Foissner 1988 n.stat.
Class Hemimastigea Foissner, Blatterer & Foissner 1988.
Diagnosis for subphylum.
Order Hemimastigida Foissner, Blatterer & Foissner 1988.
Diagnosis as for subphylum.
Family 1. Spironemidae Doflein 1916. Spironema Klebs 1922; Hemimastx Foissner, Blatterer & Foissner 1988; a third genus that show been discovered (W. Foissner, pers. commun.).