Description of Leptopharynx bromelicola n. sp. and characterization of the genus Leptopharynx Mermod, 1914 (Protista, Ciliophora)

Using morphological, morphometrical, and molecular methods, we describe Leptopharynx bromelicola n. sp. from tank bromeliads of Jamaica. We add significant data to Leptopharynx costatus and briefly characterize and review the genus Leptopharynx Mermod, 1914, including four new combinations. Nine species can be distinguished when applying the following main features and assuming that most or all have the ability to produce macrostomes (MAs): distinct ridges along the right side ciliary rows; special features like spines or wings on the body and of the oral basket; dikinetids present vs. absent from somatic kinety 3; number of kinetids in kinety 6 as two for the costatus pattern and ≥ five for the bromelicola pattern; beginning and structure of kinety 9 as either underneath or far underneath the adoral membranelles and with or without dikinetids; postoral complex present vs. absent; and preoral kinety 4 continuous vs. discontinuous. The 18S rDNA sequences of L. bromelicola and L. costatus differ by 1.7% and show that Leptopharynx forms a distinct clade within the Nassophorea Small & Lynn, 1981. Leptopharynx bromelicola is possibly closely related to Leptopharynx euglenivora Kahl, 1926, which, however, lacks the basket nose so typical of the former. Leptopharynx forms thin-walled, non-kinetosome-resorbing resting cysts maintaining most of the trophic organelles.     

Morphology,Morphogenesis and Molecular Phylogeny of a New Obligate Halophile Ciliate,Schmidtiella ultrahalophila gen. nov., spec. nov. (Ciliophora,Hypotrichia) Isolated from a Volcanic Crater on Sal (Cape Verde Islands)

A new hypotrichous ciliate, Schmidtiella ultrahalophila gen. nov., spec. nov., was isolated from a solar saltern on the island of Sal, Cape Verde. The possession of only one short dorsal kinety clearly distinguishes S. ultrahalophila from other known hypotrichous genera and species. Further diagnostic characters include: a flexible and slender body, an average size of 85 × 15 μm in vivo; a bipartite adoral zone with two hypertrophied frontal adoral membranelles and nine to twelve ventral adoral membranelles; three frontal, one parabuccal, two frontoventral, two or three postoral ventral, and two or three frontoterminal cirri; and marginal cirral rows variable in number, usually one on each side. Ontogenetic data indicate the following: the frontal‐ventral cirri originate from six or five anlagen; the proter inherits the parental adoral zone; the frontal and ventral cirri originate from five or six anlagen; and the marginal cirral rows and the dorsal kinety tend to originate intrakinetally. Additional marginal rows are rarely derived from de novo anlagen. Based on its morphology, morphogenesis and its SSU rRNA phylogenetic placement, the new species should be assigned to the order Sporadotrichida Fauré‐Fremiet, 1961. Due to low taxon sampling, however, its exact position in this order remains enigmatic.     

Morphology and ontogenesis of Platyophrya bromelicola nov. spec., a new macrostome-forming colpodid (Protists,Ciliophora) from tank bromeliads of Jamaica

Platyophrya bromelicola nov. spec. was discovered in tanks of bromeliads from Jamaica. Its morphology, ontogenesis, and small-subunit rDNA were studied using standard methods. Platyophrya bromelicola differs from its congeners mainly by the pyriform, unflattened body (vs. reniform and flattened); the free-swimming (planktonic) habit (vs. biofilm creepers); and the unique ability to form two distinct morphs, i.e., small, bacteriophagous microstomes and large, predaceous macrostomes. Microstomes and macrostomes can be distinguished not only by body size and feeding preferences but also by the postoral pseudomembrane composed of two vs. three to four dikinetids per kinety. The ability to form macrostomes is considered as an adaptation to the highly competitive habitat. Ontogenesis closely resembles that of other members of the family. Platyophrya bromelicola is distinct not only morphologically but also genetically (3.7% in the small-subunit rDNA) from P. vorax, a common, cosmopolitan moss and soil species.     

Morphology and infraciliature of two new marine ciliates, Paracyrtophoron tropicum nov. gen., nov. spec. and Aegyria rostellum nov. spec. (Ciliophora, Cyrtophorida), isolated from tropical waters in southern China

The morphology and infraciliature of two new marine cyrtophorid ciliates, Paracyrtophoron tropicum nov. gen., nov. spec. and Aegyria rostellum nov. spec., isolated from tropical waters in southern China, were investigated using live observation and protargol impregnation methods. Paracyrtophoron nov. gen. differs from the closely related Cyrtophoron by lack of fragment kinety at anterior ends of right somatic kineties and thigmotactic cilia in posterior portion of ventral surface, while from the well-defined Chlamydodon by lack of the cross-striped band around the periphery of the somatic field. Paracyrtophoron tropicum nov. spec., the type of the new genus, can be recognized by the combination of the following characters: cell size about 150-175×70-90μm in vivo; elliptical to kidney-shaped in outline, dorsoventrally flattened about 2.5:1; conspicuous cortical granules; one canal-like depression extending from postoral area to subcaudal region of cell; ca. 90 somatic kineties; 12-16 nematodesmal rods; one or two terminal fragments on dorsal side. Aegyria rostellum is characterized by the following features: size about 90-150×40-70μm in vivo, triangular or ear-shaped body with broad anterior end, having a rostriform structure and pigment spots, 56-63 somatic kineties, one preoral kinety, three or four circumoral kineties, and 32-42 nematodesmal rods. Based on previous and current studies, the definition for the genus Aegyria is updated: body dorsoventrally flattened; oral ciliature consisting of one preoral and several circumoral kineties; podite located in posterior ventral region and surrounded by somatic kineties; no obvious gap between right and left somatic kineties; postoral and left somatic kineties progressively shortened posteriorly from right to left. Additionally, two new combinations were proposed.     

Cortical structure in non-dividing and dividing Diophrys japonica spec. nov. (Ciliophora, Euplotida) with notes on morphological variation

The morphology and morphogenesis of Diophrys japonica spec. nov., isolated from the Mie Port, Nagasaki, Japan, were investigated from life and following impregnation with protargol. The new species is recognized by the following characters: Body elliptical in outline and slightly greyish to yellowish in color; size in vivo about 80-120 x 50-70 microm; pellicle flexible, with underlying granules densely arranged in lines; ciliature comprising about 30-46 adoral membranelles, 4-7 frontal, 1-4 ventral and 4-7 transverse cirri, always 1 left marginal and 3 caudal cirri, and 4 dorsal kineties; usually two macronuclear nodules; fragment kinety with 2-5 dikinetids; marine habitat. The main morphogenetic events are: (1) the opisthe's oral primordium develops de novo in a subsurface pouch near the left transverse cirri; (2) the proter retains the parental AZM except for reorganization of some proximal membranelles; (3) cirral anlagen for the frontal, ventral and transverse cirri in both dividers develop separately from the oral primordium or parental cirri, and are derived from the separation of primary primordia that originate de novo; (4) the anlagen for the left marginal cirrus and fragment kinety also form de novo and separately; (5) dorsal kinety anlagen occur within the parental structures at mid-body and posterior end of the cell, of which the right-most one contributes three caudal cirri from its posterior portion. Based on available ontogenetic data, the author proposes that the numbers of left marginal and caudal cirri can be regarded as reliable characters for species identification, while the numbers of frontal, ventral and transverse cirri are not consistent enough for species distinction. A key to the eleven adequately known species of Diophrys is presented.     

Schmidingerothrix extraordinaria nov. gen., nov. spec., a secondarily oligomerized hypotrich (Ciliophora, Hypotricha, Schmidingerotrichidae nov. fam.) from hypersaline soils of Africa

Schmidingerothrix extraordinaria nov. gen., nov. spec. was discovered in hypersaline soils from Namibia and Egypt. Its morphology and ontogenesis were studied with standard methods. Schmidingerothrix extraordinaria is a highly flexible, slender hypotrich with an average size of 90 × 15 μm. Likely, it prefers a salinity around 100‰ and feeds mainly on bacteria. Schmidingerothrix is extraordinary in having a frayed buccal lip, three-rowed adoral membranelles, only one frontal cirrus, a distinct gap between frontal and ventral adoral membranelles, and a miniaturized first frontal membranelle, while a paroral membrane, dorsal bristle rows, and buccal, transverse, and caudal cirri are absent. The ontogenesis is simple: the opisthe oral apparatus and frontoventral ciliature originate de novo, while parental structures are involved in the development of the ciliature of the proter. This special organization is used to define a new family, the Schmidingerotrichidae, which is likely related to the Cladotrichidae. Schmidingerothrix extraordinaria is very likely a secondarily oligomerized hypotrich, and the reduction occurred possibly very long ago because no traces of the ancestral ciliature remained in the ontogenetic processes. Possibly, the simple ciliature is an adaptation to highly saline habitats, where competition is low and bacterial food abundant.     

Morphology and molecular phylogeny of Oxytricha seokmoensis sp. nov. (Hypotrichia: Oxytrichidae), with notes on its morphogenesis

A new hypotrichous ciliate, Oxytricha seokmoensis sp. nov., was discovered in a soil from a forest in South Korea and described based on the observations of living and stained specimens. In addition, phylogenetic analyses were performed using the small subunit ribosomal RNA (18S rRNA) gene sequence. Morphologically, the new species is similar to the O. granulifera-complex in terms of ciliary structure and arrangement of cortical granules, but dorsal kineties 3 and 4 (not completely separated vs. separated) and macronuclear nodules in the cyst (separated vs. fused) differ. Oxytricha seokmoensis is most similar to O. pulvillus, but can be distinguished by the number of adoral membranelles (30–40 vs. 23–27), contractile vacuole (present vs. absent), number of left (27–37 vs. 17–25) and right (27–35 vs. 18–23) marginal cirri, and lepidosomes on the cyst surface (present vs. absent). In a phylogenetic tree, O. seokmoensis is distinctly separated from the O. granulifera clade, but is sister to the Paroxytricha clade. In addition, O. seokmoensis and P. longigranulosa have the smallest genetic difference (d = 0.015, 23 of 1579 nt difference). This close relationship is supported by incomplete dorsal kinety 3 fragmentation and separated macronuclear nodules in resting cysts.     

Evolution of ciliary patterns in the Oligotrichida (Ciliophora, Spirotricha) and its taxonomic implications

Although the somatic ciliature of the Oligotrichida typically comprises only a girdle and ventral kinety, a considerable diversity of ciliary patterns occurs. The four main girdle kinety patterns are identically found in tailed and tail-less species. The contractile tail has a complicated and unique ultrastructure and is potentially useful for the cell's movement and/or stabilization during feeding. Accordingly, I assume that this structure has evolved only once, namely, in the Tontoniidae nov. fam., and that the different girdle kinety patterns developed convergently in the tailed and tail-less taxa. Further distinct features suggest the establishment of the families Cyrtostrombidiidae nov. fam. (with cyrtos-like pharyngeal fibres and lack of ventral membranelles and endoral) and Pelagostrombidiidae nov. fam. (with neoformation organelle). An attempt is made to reconstruct the evolution of the kinety patterns based on morphologic, ontogenetic, and ultrastructural data. Some genera of tail-less Oligotrichida base on differences in the ciliary pattern; Omegastrombidium nov. gen. is erected for a further girdle kinety pattern. Likewise, the tailed genus Tontonia is split, resulting in two new genera, viz., Pseudotontonia nov. gen. and Spirotontonia nov. gen. Furthermore, the genus Spirostrombidium is split due to the different origin of the parallel course of girdle and ventral kinety, and Parallelostrombidium nov. gen. is established. However, the genus Thigmostrombidium is rejected because its enlarged thigmotactic membranelles are interpreted as an adaptation to the benthic lifestyle, which occurred several times within different girdle kinety patterns.     

Morphological and molecular characterization of Aspidisca hongkongensis spec. nov. (Ciliophora,Euplotida) from the South China Sea

The morphology and infraciliature of a new ciliate, Aspidisca hongkongensis spec. nov., a large marine form isolated from the coastal waters near Hong Kong, were investigated. It differs from the congeners by the combination of cell size (about 90×60 μm in vivo), 9–11 conspicuous dorsal ridges, one fine and seven strong frontoventral cirri, six membranelles in anterior portion of adoral zone, and 17–23 membranelles in posterior portion of adoral zone. The comparison with similar congeners clearly supports the distinction of this new species based on morphological and small subunit (SSU) rRNA gene sequence studies. The SSU rRNA gene sequence similarity within the genus is about 75.3–92.1% which indicates that this is a distinct form. Phylogenetic trees based on SSU rRNA gene information show that A. hongkongensis groups with A. leptaspis.     

Morphology and Ecology of Siroloxophyllum utriculariae (Penard, 1922) N. G., N. Comb. (Ciliophora, Pleurostomatida) and an Improved Classification of Pleurostomatid Ciliates

ABSTRACT. The morphology and infraciliature of Siroloxophyllum utriculariae (Penard, 1922) n. g., n. comb. were studied in live cells, with the scanning and transmission electron microscope, as well as in specimens impregnated with protargol and silver carbonate. The new genus, Siroloxophyllum , belongs to the Loxophyllidae and has a specific combination of characters, viz. an oral bulge surrounding almost the entire cell, three perioral kineties, a single brush kinety, and a single right dorsolateral kinety. The ecology and faunistics of S. utriculariae are reviewed. It is a rare and infrequent predator preferring clean freshwaters. The somatic monokinetid of S. utriculariae has typical haptorid ultrastructure, including two transverse microtubular ribbons. The oral bulge is patterned string-like with riffles containing the transverse microtubular ribbons originating from the oral kinetids. Perioral kineties 1 and 2 consist of dikinetids having one basal body each ciliated; the nonciliated basal body is associated with a nematodesmal and a transverse microtubular ribbon. Perioral kinety 3 consists of ciliated monokinetids having a fine structure similar to the somatic kinetids; they form triads with the dikinetids from perioral kinety 2. The classification of pleurostomatid ciliates is reviewed. Two suborders (Amphileptina, Litonotina) and three families (Amphileptidae, Litonotidae, Loxophyllidae n. fam.) are recognized and defined.     

Rubrioxytricha guamensis nov. spec. (Ciliophora,Spirotricha), a Novel Hypotrich Ciliate from Guam (United States), Micronesia

The oxytrichid ciliate Rubrioxytricha guamensis nov. spec. isolated from water samples collected from a small freshwater pond near the Hagåtña River in Hagåtña, Guam (United States territory), Micronesia, was investigated, using live observation and protargol impregnation. The morphology, ontogenesis, and molecular phylogeny inferred from the small‐subunit rRNA gene sequences were studied. The new species is mainly characterized by a cell size of about 100 × 35 μm in vivo, two elongate ellipsoidal macronuclear nodules and two micronuclei, a single contractile vacuole, a colorless cytoplasm, yellowish cortical granules, arranged in short rows and in small groups, an adoral zone occupying about 34% of body length and comprising 27 membranelles on average, about 27 cirri each in the right and left marginal rows, 18 frontoventral transverse cirri, four dorsal kineties including one dorsomarginal row, and one or two caudal cirri at the posterior end of dorsal kinety 3. The ontogenesis of the new species is similar to that of Rubrioxytricha indica Naqvi et al., 2006. Phylogenetic analyses based on SSU rRNA gene sequences consistently place the new species within the family Oxytrichidae Ehrenberg, 1838, where it clustered with other Rubrioxytricha species, viz., R. tsinlingensis, R. ferruginea, and R. haematoplasma.     

Participation of the Undulating Membrane in the Formation of Oral Replacement Primordia in Tetrahymena pyriformis*

SYNOPSIS. Cells of T. pyriformis GL-C, transferred from a complete axenic medium to a medium lacking amino acids, cease dividing after several hours, and instead begin to undergo oral replacement. This process can be synchronized by a single long 33.8 C treatment. Oral replacement was also observed during stationary phase of normal culture growth in cells of strain GL-C and WH-6 (syngen 1). In strain GL-C the oral replacement primordium is initiated by the appearance of a small number of kinetosomes adjacent to the anterior end of kinety 1, just posterior to the undulating membrane (UM). The UM then loses its cilia and becomes disorganized, and is thus converted into a field of kinetosomes which is broadest near its posterior end. This UM-derived field then becomes joined with the much smaller field which had appeared earlier near the anterior end of kinety 1. As a consequence, the right margin of the UM-derived field becomes continuous with the anterior end of kinety 1, and thus comes to appear as an anterior extension of this kinety. The membranelles and UM of the new oral area differentiate within this composite field. While this is going on, the membranelles of the old oral area are progressively resorbed; these old membranelles always remain spatially separate from the oral replacement primordium. In strain WH-6, the stomatogenic field initially formed adjacent to kinety 1 is substantial, and the role of the UM kinetosomes in stomatogenesis is less obvious than in strain GL-C. The posterior portion of the UM probably contributes to the oral replacement primordium, while the anterior portion is resorbed. In this strain small supernumerary primordia are occasionally seen adjacent to the portion of kinety 2 which is nearest to the posterior region of the UM. It is suggested that the junction between the posterior portion of the UM and the neighboring cortex can serve as an inductive zone for initiation of stomatogenesis, the UM itself having a varying capacity for direct provision of kinetosomes for the stomatogenic field. The flexibility of the stomatogenic site in T. pyriformis is discussed in relation to the apparent restriction of potentialities in peniculine ciliates such as Paramecium.     

Morphology of Clapsiella magnifica gen. n., sp. n., a new hypotrichous ciliate with a curious dorsal ciliary pattern

The present work describes the morphology and infraciliature of a new hypotrichous ciliate, Clapsiella magnifica gen. n., sp. n., found in rewetted soil from a temporal pond in Argentina. It was studied by means of live observation and protargol impregnation. Its main diagnostic features are: Flexible hypotrich measuring 250–320 μm × 70–140 μm in vivo; two macronuclear nodules and 4–6 micronuclei. Single contractile vacuole. Cytoplasm transparent, cortical granules absent. Somatic ciliature composed of a tricorona of cirri, three buccal(?) cirri, 6–9 ventral rows, 3–5 right marginal(?) rows, one left marginal row, and 12–17 transverse cirri. Dorsal pattern rather complicated, with about 14 kineties and kinety fragments, with scattered kinetids among them; 17–28 caudal cirri arranged in three rows on dorsal kineties 1, 3, and 7. Remarkably, dorsal kinetids have two or four basal bodies, bearing a stiff bristle arising from left anterior basal body. Adoral zone composed of 70–92 membranelles, occupying about 40% of body length in protargol preparations; paroral and endoral curved, resembling a cyrtohymenid pattern. The peculiar dorsal ciliary arrangement and the unique combination of other characters require the establishment of a new genus for this new species, which is considered incertae sedis in the Hypotricha but possibly related to the oxytrichids.     

Spirotontonia taiwanica n. sp. (Ciliophora: Oligotrichida) from the Coastal Waters of Northeastern Taiwan: Morphology and Nuclear Small Subunit rDNA Sequence

ABSTRACT. The marine oligotrichous ciliate Spirotontonia taiwanica n. sp. isolated from the coastal waters of northeastern Taiwan is reported, using live observation, protargol preparations and molecular data. The new species differs from the most similar, known congener Spirotontonia turbinata in the following features: (1) lower number of buccal membranelles (11–13 vs. 13–17); (2) higher number of whorls of girdle kinety (2.5 vs. 1.5); (3) lower number of macronuclear nodules (20–31 vs. 28–40); (4) larger cell size (80–104 × 40–72 vs. 44–75 × 29–56 μm); (5) larger anterior cell end to buccal vertex (50 vs. 33 μm); (6) larger ratio of cell length to cell width (1.74 vs. 1.38); (7) the different beginning of the girdle kinety (posterior to the buccal vertex vs. left of the buccal zone portion); and (8) the disappearance of the L‐shaped argyrophilic structures in the last half whorl and occasionally the first 1–10 dikinetids (i.e. yes vs. no). The molecular data also reveal two distinct species, deviating by 2% or 33% base pairs.     

Description of Four New Soil Dileptids (Ciliophora, Haptoria), with Notes on Adaptations to the Soil Environment

We studied the morphology of four new dileptid ciliates, using standard methods. Dileptus microstoma, which was discovered in Benin (Africa), is outstanding in having a very small oral opening (~4 μm), an interrupted dorsal row of contractile vacuoles, and ampulliform extrusomes. Dileptus semiarmatus, which was discovered in Austria, possesses extrusomes only in the right posterior half of the proboscis and has very widely spaced circumoral and perioral kinetids. Dileptus longitrichus, which was discovered in Japan, is almost unique in having up to 15 μm long brush bristles and a row of contractile vacuoles each in ventral and dorsal side of body. Pseudomonilicaryon brachyproboscis, which was discovered in Greece, differs from the congeners by the narrowly ellipsoidal micronuclei, the dimorphic dorsal brush, the extrusomes, and the contractile vacuole pattern. Four new features are introduced for distinguishing species in dileptids: shape of micronucleus, monomorphic/dimorphic dorsal brush, shape of oral opening, and spacing of circumoral dikinetids. The terrestrial dileptids share several distinct morphological features that are probably adaptations to the soil environment: (1) the body is comparatively slender and small, what is likely related to the narrowness of the habitat; (2) the proboscis is short, which increases the relative volume of the trunk, what might be related to its fragility and/or to the space available for prey digestion; (3) the long dorsal bristles might foster prey recognition; and (4) the pronounced body flexibility in all dileptids likely fosters their high diversity in the narrow and wrinkled soil habitat.     

Morphology and molecular phylogeny of two new soil ciliates,Hemiurosomoida warreni nov. spec. and Hemiurosoma clampi nov. spec. (Ciliophora,Hypotrichia) from Tibet

Two novel hypotrichous ciliates, Hemiurosomoida warreni nov. spec. and Hemiurosoma clampi nov. spec., isolated from soil in the Lhalu Wetland and Motuo Virgin Forest in Tibet, respectively, were investigated using live observation and protargol staining. Hemiurosomoida warreni nov. spec. strongly resembles the type species H. longa but can be distinguished by its body size in vivo (110–145 × 30–40 μm vs. 50–100 × 18–40 μm), number of adoral membranelles (25–38 vs. 15–22), and numbers of right (29–39 vs. 14–23) and left (26–35 vs. 13–23) marginal cirri, transverse cirri (3 vs. 4 or 5) and macronuclear nodules (4–8 vs. 2). Hemiurosoma clampi nov. spec. is characterized by its vermiform body shape, colourless cortical granules distributed in irregular rows, two macronuclear nodules, three frontal cirri, one buccal cirrus, four frontoventral cirri ranged in a line, two transverse cirri, lacking postoral ventral and pretransverse ventral cirri, and marginal rows that are not posteriorly confluent. Phylogenetic analyses based on SSU rDNA gene sequences suggest that Hemiurosomoida is not monophyletic. A close relationship is revealed between Hemiurosomoida warreni nov. spec., Parakahilella macrostoma, Hemiurosoma clampi nov. spec., and the type species Hemiurosoma terricola. As expected, all these species are classified within the “non-oxytrichid Dorsomarginalia”.     

Updating the Trachelocercids (Ciliophora, Karyorelictea). I. A Detailed Description of the Infraciliature of Trachelolophos gigas N. G., N. Sp. and T. filum (Dragesco & Dragesco-Kernéis, 1986) N. Comb

ABSTRACT. Trachelolophos gigas n. g., n. sp. and T. filum (Dragesco & Dragesco-Kernéis, 1986) n. comb. (basionym: Tracheloraphis filum) were discovered in the mesopsammon of the French Atlantic coast at Roscoff. Their morphology and infraciliature were studied in live and protargol impregnated specimens. The new genus, Trachelolophos, belongs to the family Trachelocercidae and is unique in having a conspicuous ciliary tuft, which is very likely a highly modified brosse, in the oral cavity. The two species investigated have a very similar infraciliature, differing only in morphometric characteristics and in the nuclear configuration. The entire somatic and oral infraciliature consists of dikinetids which have both basal bodies ciliated or only the anterior or posterior ones, depending on the region of the cell. The right side is densely and uniformly ciliated. Its kineties extend onto the left side to the glabrous stripe, where an anterior and posterior secant system are formed, reducing the number of kineties in the narrowed neck and tail region. The left side bears a narrow glabrous stripe bordered by slightly irregularly arranged dikinetids having rather stiff cilia (bristles), possibly forming an uninterrupted, prolate ellipsoidal (bristle) kinety as indicated by their ciliation. The bristle kinety commences subapically at the right margin of the glabrous stripe, extends posteriorly, then anteriorly at the left, to end up at the right margin again. The dikinetids of the right posterior portion of the bristle kinety have the posterior basal bodies ciliated, whereas the anterior basal bodies are ciliated in its left and right anterior portion. The ends of the bristle kinety meet distinctly subapically at the right margin of the glabrous stripe, as indicated by the diametrically opposed ciliation of the dikinetids. The anterior region (head) of the cell bears a distinct circumoral kinety composed of very regularly arranged dikinetids, associated with nematodesmata forming an oral basket together with the nematodesmal bundles originating from the oralized somatic dikinetids at the anterior end of the somatic kineties. The systematics of trachelocercid ciliates are briefly reviewed and discussed.