Description of the Infraciliature and Morphogenesis in the Ciliate Urotricha ondina N. Sp. (Prorodontida, Urotrichidae)

Recent works on prostomatid ciliates show that some genera of this group have a differentiated oral infraciliature and that their stomatogenesis during division involves the proliferation of only a few somatic kineties. These findings have significant implications regarding the iaxonomic status of these genera and also on the terminology used for the oral structures. In Urotricha ondina , the oral infraciliature consists of (1) a paroral kinety formed of paired kinetosomes that encircle the cytostome at the anterior pole of the cell and (2) 3 adoral organelles, each formed of 2 rows of kinetosomes, ventral in position and obliquely disposed, lying above 3 short somatic kineties that do not reach the anterior pole of the cell. This oral ciliature —formerly known as the corona and brosse, respectively—originate during stomatogenesis from the proliferation of 4 somatic kineties that lie posterior to the adoral organelles of the parental cell.     

Somatic kinetics or paroral membrane: which came first in ciliate evolution?

The ciliate species which lack a distinctive oral ciliature are considered to represent an ancestral state in ciliate evolution. Consequently, the somatic kineties composed of kinetids (kinetosomes plus cilia and associated fibrillar systems) are thought to be the ancestral ciliature. Results on stomatogenesis in 'gymnostomial ciliates' have shown that these ciliates probably have evolved from ancestors already equipped with an oral ciliature. Thus instead of the somatic, the oral ciliature may be regarded an ancestral. Based on these ideas a hypothesis on the evolution of the ciliate kinetome (assembly of all kinetids covering the body of a given ciliate) is presented. The first step in the evolution of the kinetome was the formation of a paroral membrane, a compound ciliary organelle lying along the right side of the oral area which historically but falsely is termed membrane. It was composed of kinetosomal dyads (dikinetids), derived from the kinetid of a dinoflagellate-like ancestor. From the beginning the paroral membrane was responsible for locomotion, ingestion and for the formation of a cytopharyngeal tube which the first ciliate probably had inherited from its flagellate ancestor. In the second step a first somatic kinety was formed from the right row of kinetosomes of the paroral membrane as a result of a longitudinal splitting of the paroral membrane and a subsequent migration of the forming kinety to the right into the somatic cortex. To increase the number of somatic kineties this process was repeated until the kinety produced first reached the left border of the oral area. By this step the locomotive and the nutritional functions were differentiated between somatic and oral structures. In a third step the adoral organelles were formed from somatic kinetids left of the oral area. The primitive type of stomatogenesis was a buccokinetal one derived from the mode the flagellate ancestor used to distribute its replicated kinetosomes to the offspring cells (buccokinetal means that at least parts of the oral anlage for the posterior offspring cell has its origin in the parental oral apparatus). This hypothesis, based on comparative studies on ciliate morphogenesis, is corroborated by molecular data from other laboratories.     

钩刺斜管虫无性生殖期间的口纤毛器及细胞发生研究（原生动物：纤毛虫）

钩刺斜管虫口和体纤毛器演化模式是研究该类动物个体发生的优秀模型。通过跟踪研究,澄清了后仔虫口器发生以及体纤毛器起源上的几点疑问,并证实：体左侧二列片段动基列为同源再造而非来自老结构的分裂或复制;三列围口纤毛均为双动基列构造;后仔虫口原基场的构建系由５列体动基列共同参与完成的,其中最左侧两列短的原基片段与原基１整合为一体,从而发展成营养期虫体的外围口动基列;后仔虫背触毛原基为独立发生。     

Description of the Halophile Euplotes qatarensis nov. spec. (Ciliophora,Spirotrichea, Euplotida) Isolated from the Hypersaline Khor Al‐Adaid Lagoon in Qatar

The morphology, ontogenesis, and phylogenetic relationships of a halophile euplotid ciliates, Euplotes qatarensis nov. spec., isolated from the Khor Al‐Adaid Lagoon in Qatar were investigated based on live observation as well as protargol‐ and silver nitrate‐impregnated methods. The new species is characterised by a combination of features: the halophile habitat, a cell size of 50–65 × 33–40 μm, seven dorsal ridges, 10 commonly sized frontoventral cirri, two widely spaced marginal cirri, 10 dorsolateral kineties, and a double silverline pattern. The morphogenesis is similar to that of its congeners: (i) the oral primordium develops hypoapokinetally and the parental oral apparatus is retained; (ii) the frontoventral‐transverse field of five streaks gives rise to the frontal, ventral, and transverse cirri, but not to the cirri I/1 and the marginal cirri; (iii) the dorsal somatic ciliature develops by intrakinetal proliferation of basal bodies in two anlagen per kinety that are just anterior and posterior to the future division furrow; (iv) the caudal cirri are formed by the two rightmost dorsolateral kineties. The SSU rDNA sequence of E. qatarensis branches with full support in the Euplotopsis elegans–Euplotes nobilii–Euplotopsis raikovi clade. The closest related publicly available SSU rDNA sequence is the one of E. nobilii, with which E. qatarensis has 93.4% sequence similarity. Euplotes parawoodruffi Song & Bradbury, 1997 is transferred to the genus Euplotoides based on the absence of frontoventral cirrus VI/3.     

Morphology and Morphogenesis of Two Species of the Genus Lembadion (Ciliophora, Oligohymenophora): Lembadion lucens and Lembadion bullinum

ABSTRACT. The morphology and morphogenesis of two species of the genus Lembadion, L. lucens and L. bullinum , are described. In both species, left and right ventral kineties converge behind the mouth forming a postoral suture. Buccal infraciliature is formed by one polykinety and two very close paroral kineties (inner and outer). During stomatogenesis, the new oral structures originate from the paroral kineties. The inner paroral kinety forms the new adoral polykinety and regenerates the outer paroral kinety of the proter, while the paroral kineties of the opisthe originate from the outer paroral kinety of the parental cell. Somatic proliferation starts before the stomatogenesis at the equatorial level of the cell, and extends towards the poles forming an equatorial band. Two large invariant zones, anterior and posterior, remain in the dividing cell. Moreover, the kinetodesmal fibers disappear in the proliferation band during the bipartition (fission) process.     

Morphogenesis and Cortical Ultrastructure of Brooklynella hostilis,a Dysteriid Ciliate Ectoparasitic on Marine Fishes*

SYNOPSIS. Morphogenesis, and the cortical structures of Brooklynella hostilis, a cyrtophorine gymnostome ciliate ectoparasitic on marine fishes, were studied from protargol silver-impregnated preparations and with the aid of electron microscopy. The pattern of morphogenesis of Brooklynella is close to that found in less differentiated species of the families Chlamydodontidae (e.g., in the genus Trithigmostoma) and Dysteriidae (e.g., in the genus Hartmanula). The full number of kineties in the opisthe is restored after division from a segment of the left one of the 3 kinetics producing the oral rows. The oral rows consist of a double row of kinetosomes arranged in a zig-zag pattern; only the outer row is ciliated, the inner one being barren. However, the positions of the postciliary and transverse fibers indicate that the oral rows are not homologs of an undulating membrane but are akin to a membranelle. In association with the ventral somatic kinetosomes there are 4 postciliary fibers; a rather aberrant, transversally oriented kinetodesma; 2 microtubular, transverse fibers plus a transverse fibrousspur; and one to several ribbons of subkinetal microtubular fibers. Not directly associated with the kinetosomes are fibrous strands running subpellicularly between the kinetosomes and also deep into the cytoplasm. The cortical structures of Brooklynella are compared with those of some other groups of ciliates of about the same phylogenetic level in which the subkinetal microtubules can also be found– rhynchodine, suctorian, and chonotrich ciliates. The nasse consists of 6–8 nematodesmata not closely associated with the microtubular cytopharyngeal tube. The former have a distinctly developed densely fibrous capitulum containing barren kinetosomes which originally produced the nematodesma during stomatogenesis; the capitulum is connected by a fibrous link to the microtubular shaft. Extending from the oral rows to the capitula are fibrous structures strongly reminiscent of filamentous reticulum in hymenostome and peritrich ciliates. The structure of the posterio-ventral glandular organelle is also described and discussed.     

Evidence for Hymenostome Affinities in an Apostome Ciliate

The functional mouth of exuviotrophic apostome ciltates appears only after an elaborate metamorphosis that begins at the onset of the molting of their crustacean hosts. In the tomite. a non-feeding migratory stage, a mid-ventrai depression at the origin of kineties x, y and z has been misidentified as the cytostome. Studies of fine structure and morphogenesis identify the true but nonfunctional cytostome—the subapiral lateral canal —and the falciform and ogival fields as the adoral ciliature. The anterior row of barren kinetosomes that parallels on the right the anterior third of the lateral canal is actually the infraciliature of a paroral. 2 rows of barren staggered kinetosomes. The canal itself is a narrow tube, its walls partially lined with microtubules. It begins 2–3 μm from the apex of the body and passes between falciform field 9 and the ogival field to end near the end of the ogival field. The fine structure of the infraciliature of the falciform and ogival fields differs markedly from that of the somatic kineties. In the host's early pre-molt stages, the paroral migrates across the ventral surface of the encysted phoront and is accompanied by the microtubules of the lateral canal. The anterior end of falciform field 9 disorganizes into scattered kinetosomes, the trophont's anterior field of kinetosomes, but the posterior end migrates in an arc across the anterior ventral surface and remains as kinety a located near the angle where kinety 1 sharply par ra continues posteriad ind dorsad to the posterior limit of the extended cytostome. At the end of metamorphosis it sinks into The cytoplasm and disappears. The completion of the extended cytostome, the functional mouth, marks the termination of the microstome-macrostome transformation. The fine structure of the infraciliature and microtubular elements making up the macrostome and the evocation of the microstome-macrostome transformation in the presence of specific foods suggest that apostome ciliates any more properly be a suborder of Hymenostomatida rather than a subclass of Oligohymenophorea.     

A New Species of the Genus Metacystis (Ciliophora,Prostomatida, Metacystidae) from a Wastewater Treatment Plant

ABSTRACT. Unusual prostomatid specimens were found in the biological reactor of a wastewater treatment plant in a health resort in Valencia, Spain. These ciliates were attached to flocs unlike other free‐swimming prostomatid ciliates described to date in the mixed liquor of activated sludge plants. The morphological study of this species led to a typically different combination of characteristics: elongated cell shape, 20–30 somatic kineties, 2 perioral kineties, and 1 circumoral kinety, 1 large vacuole protruding at the terminal end, a lorica tapered toward the aperture with a smooth neck, and 11–16 annular ridges. These characteristics place this representative as a new species of the genus Metacystis—Metacystis galiani n. sp. This species became the dominant population within the biological reactor when high values of conductivity (4,244 mS/cm) and temperature (26.8 °C) were recorded.     

Morphogenèse de Régénération chez le CiliéCondylostoma magnum (Spiegel): Etude ultrastructurale

SYNOPSIS Cortical events occurring in the course of regeneration in Condylostoma magnum (Spiegel) were studied by electron microscopy. The zone of regeneration is very rich in vacuoles and small vesicles formed from the plasma membrane. Multiplication of kinetosomes starts on the left side of kineties in the V-shaped left ventral area, normally implicated in stomatogenesis, at the level of the anterior kinetosomes of the somatic pairs. The proliferation proceeds by the appearance of young kinetosomes most often orthogonal to the old ones. This process of multiplication is very rapid and terminates in the formation of an “anarchic field” in which one observes that: (a) the newly formed kinetosomes do not possess all the associated postciliary fibers; and (b) when these fibers are detected, the kinetosomes are not in the same orientation. Differentiation of the adoral organelles takes place in the left part of the field (left primordium) by an alignment of the kinetosomes into 2 rows for each organelle (oriented perpendicularly to the antero-posterior axis of the ciliate), of which only one has the postciliary fibers. Ciliatogenesis occurs in numerous kinetosomes of the anarchic field; in certain kinetosomes it is achieved at the onset of their arrangement into organelles and is concomitant with growth of the nematodesmata. The 3rd (anterior) row of the organelles, the interkinetosomal desmata, and connections among neighboring organelles appear only secondarily. Differentiation of the paroral cilia occurs later. It takes place in the interior of the primordium, whose organization is primarily anarchic, and is accompanied by a progressive resorption of the major part of the newly formed kineties. Numerous kinetosomes of the right field have the associated postciliary fibers, which are not found at the level of the regenerated “polystichomonad” (paroral organization characteristic of C. magnum). Finally, the formation of new kinetosomes within a somatic kinety at the time of its elongation is described.     

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,morphogenesis and phylogeny of Anteglaucoma orientalis n. sp. (Ciliophora,Oligohymenophorea), a freshwater hymenostomatid from northeastern China

A new hymenostomatid ciliate, Anteglaucoma orientalis n. sp., isolated from a freshwater pond in Harbin, northeastern China, was investigated using live observation and silver staining methods. Anteglaucoma orientalis is characterized as follows: size in vivo about 50–60 × 30–35 μm; oval body shape; buccal area occupies about 25% of body length; 28–36 somatic kineties; membranelle 1 having six or seven basal body rows, membranelle 2 five to seven rows, and membranelle 3 three rows; single macronucleus with one micronucleus attached. Morphogenesis of the genus Anteglaucoma is revealed for the first time. The main events during binary fission are as follows: morphogenesis begins with proliferation of kinetosomes in the middle part of postoral kinety 1, and kinetosomes of this primordial field multiply and organize to finally form the paroral membrane and membranelles 1–3 of the opisthe; the parental apparatus in the proter does not take part in the stomatogenetic process. Phylogenetic analyses based on SSU rRNA gene sequences show that Anteglaucoma orientalis n. sp. clusters with the type species, A. harbinensis Pan et al., 2017, with full support.     

The Fine Structure of the Mature Tomite of Hyalophysa chattoni

SYNOPSIS. The fine structure of the tomite stage of Hyalophysa chattoni was examined with particular attention to its kinetal apparatus. The pellicle, thick and dense compared with that of other ciliates, is formed of three layers. The inner layer is composed of short fibrils oriented perpendicular to the surface. The cytoplasm around the oral passage and beneath falciform field 8 is crowded with dense inclusion bodies of unknown function. Dorsal to the oral passage is the rosette, a disc-shaped organelle subdivided by septa in the form of incomplete radii about a central chamber containing a tuft of cilia. The septa are composed of 3 membranes enclosing a fine layer of cytoplasm. At their inner ends 20 mμ fibers run dorsally and ventrally. Dense clumps of fibrous material line the luminal surface of the septa. Rows of fusiform trichocysts parallel the kineties. The trichocysts are composed of a finely periodic, moderately electron-dense material surrounded by 20 mμ fibrils oriented along the long axis of the trichocyst. Between and below the kinetosomes and the rows of trichocysts are electron-dense vesicles 300 mμ in diameter and bounded by a loose membrane. The large “trichocysts,” the “gros trichocystes” of Chatton and Lwoff, whose appearance heralds the beginnings of trichocystogenesis, prove to be canaliculi opening to the surface. Four separate ciliary membrane systems—the oral ciliature (XYZ), falciform field 8, falciform field 9, and the ogival field—are located on the ventral surface of the tomite. Each differs from the others and from the somatic kineties in the fibrillar organization around its kinetosomes. In the somatic kineties the kinetodesmos is a dense, periodic fiber which is formed of stacks of up to 18 subfibers, each arising from the base of a kinetosome. The kinetosomes are short (300 mμ) and contain dense central granules. In some kineties, alternating between the kinetosomes, are elliptical kinetosome-like structures which do not bear cilia and perhaps provide a reservoir of kinetosomes for future growth of the kinety.     

Establishment of a new hypotrichous genus,Heterotachysoma n. gen. and notes on the morphogenesis of Hemigastrostyla enigmatica (Ciliophora,Hypotrichia)

A marine hypotrich ciliate, Heterotachysoma multinucleatum (Gong and Choi, 2007) n. comb., found in coastal waters near Qingdao, China, was investigated. Heterotachysoma multinucleatum is characterized by its dorsal ciliature arranged in Gonostomum-pattern. Additionally, a new genus, Heterotachysoma n. gen., is established which is mainly characterized by: 18-cirri pattern; flexible body; three dorsal kineties with no dorsomarginal kineties nor kinety fragmentation; one right and one left row of marginal cirri; caudal cirri absent. The genus Tachysoma is redefined, and three new combinations, T. multinucleatum, T. ovatum and T. dragescoi, are proposed. The morphogenesis of Hemigastrostyla enigmatica (Dragesco and Dragesco-Kernéis, 1986) Song and Wilbert, 1997, is also described. Compared with that of its congeners, the differences are mainly in the dorsal ciliature: (1) the dorsal kinety anlagen are formed de novo in H. enigmatica (vs. intrakinetally in H. paraenigmatica and H. elongata); (2) the dorsal kineties anlagen develop in secondary mode in H. enigmatica (vs. primary mode in H. paraenigmatica); (3) the kinetal fragment anterior to the right marginal row in both filial product is absent in both H. enigmatica and H. elongata (vs. present in H. paraenigmatica). These findings suggest that morphogenesis is not uniform among members of the genus Hemigastrostyla.     

Intraclonal Dimorphism of Caudal Cirri in Euplotes vannus: Cortical Determination*

SYNOPSIS. Intraclonal variation in number of right caudal cirri (RCC) occurs within some species of the hypotrichous genus Euplotes. Euplotes vannus, a marine species, may have either 2 or 3 RCC. A single clone always contains individuals of both types. The frequency of individuals of each type within a clone was found to be 0.5. This fact suggested that during division each parental cell gives rise to one daughter having 3 RCC and one having 2. Formation of RCC during division was studied in E. vannus and in E. plumipes, a fresh-water form which always has 2 RCC. The studies were made on living animals and on fixed animals stained with protargol or by the Chatton-Lwoff method. In both species, the new RCC first appear in the right dorsal kineties and later migrate to the ventral surface. The RCC for the proter develop near the parental equator while those for the opisthe form near the posterior end of the parent cell, both sets developing in close proximity to kinetosomes of the kineties. In both species the 2 dorsal kineties furthest to the right each give rise to 2 RCC, one for the proter and one for the opisthe. In E. vannus, however, the third-from-the-right dorsal kinety also produces one right caudal cirrus for the proter. Therefore, in E. vannus it is the proter which always receives 3 caudal cirri and the opisthe which gets only 2. The role of the cortex in determining these events is discussed. Two cases of abnormal caudal cirrus formation are also described. Other aspects of morphogenesis during division, not previously reported, are also presented and discussed.     

Trimyema compressum Lackey, 1925: Morphology,Morphogenesis and Systematic Implications1

ABSTRACT Trimyema compressum is a species included in the family Trimyemidae with the single genus Trimyema. This species has 50–60 somatic kinetics and three rows of kinetosomes surrounding the oral cavity. Two isolated groups of kinetosomes can also be observed on the right side of the oral region. The morphogenesis of bipartition is telokinetal; all the new infraciliary structures of the opisthe come from the longitudinal and postero-anterior proliferation of the last kinetosome of all the somatic kinetics. In the proter there is a reorganization of the oral infraciliature. As a result of our observations, we suggest that the systematic position of the genus Trimyema be changed from the subclass Vestibulifera to the subclass Gymnostomata. We also consider that this genus must be included in the suborder Trimyemina Jankowski, 1980.     

The Fine Structure of Saprodinium dentatum Lauterborn, 1908 as a Representative of the Odontostomatida (Ciliophora)

The fine structure of the sapropelic ciliate Saprodinium dentatum is described based on phase-contrast microscopy, silver-staining techniques, cryo-fracture scanning electron microscopy, and thin sections. The study concentrates on a detailed analysis of the somatic cortex and the oral ciliature of this highly asymmetric, laterally compressed ciliate. The cell shape is dominated by a number of site-specific spines and the curving course of 10 somatic kineties (SK 1–10). The SK, composed of dikinetids, show an intrakinety differentiation that seems characteristic for other odontostomes as well. The anterior segment of the SK is mostly ciliated, followed by a non-ciliated segment in which the kinetosomes lack all typical fiber systems. Except for SK 4–6, the posterior segment is ciliated again, forming the spine kinetics associated with particular caudal spines. The anterior segment of SK 3 through SK 7 form the frontal band, which together with the two frontal kineties constitutes the main locomotory organelle for a ciliate that creeps on the substratum. A short kinety with inverse polarity, not seen in earlier light microscopical studies, was observed near the oral spine. We made particular effort to find a logical explanation for the observed association of the SK with the various caudal spines. The oral ciliature consists of nine adoral organelles located in a tripartite oral cavity. The absence of a paroral ciliature together with the position of the cytostome anterior to the adoral organelles may be the result of rotational movement of the oral apparatus during the evolution of these bizarre ciliates. Results are discussed with special reference to the phylogenetic relationship of the Odontostomatida to the Heterotrichida and no conclusive answer was found in this first electron microscopical study of an odontostomatid ciliate.     

Morphologie,Infraciliatur und Ökologie der limnischen Tintinnina: Tintinnidium fluviatile Stein,Tintinnidium pusillum Entz,Tintinnopsis cylindrata Daday und Codonella cratera (Leidy) (Ciliophora,Polyhymenophora)*

Synopsis. Structure, infraciliature, and ecology of 4 fresh-water Tintinnina were investigated. The lorica of Tintinnidium fluviatile is gelatinous, fragile, and contains some agglutinated material mainly of biologic origin. Its infraciliature consists of ? 10 kineties. with kinetosomes arranged in pairs. Only one basal body of a pair is ciliated, except for the uppermost 1–4 pairs which have 2 slightly elongated cilia. In Tintinnidium fluviatile. Tintinnidium pusillum, and Tintinnopsis cylindrata there are 2 prominent ventral organelles. The lorica of T. pusillum is gelatinous and coated with much agglutinated material of biologic and nonbiologic origin. Its infraciliature is similar to that of T. fluviatile, but the uppermost pair of kinetosomes has elongated cilia. The firm loricae of T. cylindrata and Codonella cratera are, built mainly of sharp-cornered structures. The infraciliature of T. cylindrata is composed of ? 10 kineties with kinetosomes not arranged in pairs. The infraciliature of C. cratera consists of ? 32 kineties, in some of which the kinetosomes are paired, e.g. ventral kinety, and in others not paired, e.g. cilia of the very prominent lateral field and of the other somatic kineties. The uppermost kinetosomes of each somatic kinety are paired and have elongated cilia. In addition, there is an unusual ventro-lateral kinety. The oral apparatus consists of adoral membranelles and a paroral membrane. The membranelles that enter the praecral cavity are very elongate, a feature perhaps unique to Polyhymenophora. The fibrillar system consists of a prominent praeoral ring formed by fibrils extending from the adoral membranelles. A finely meshed silverline system extends over the entire cell. A review of the ecology of the fresh-water Tintinnina indicated that water temperature seems to be the most essential ecologic factor. The systematic position of the Tintinnina is discussed in light of their infraciliature. It is concluded that these organisms are most closely related to Oligotrichina, and probably to Heterotrichina.     

Morphological and phylogenetical studies on a new soil hypotrich ciliate: Kahliella matisi spec. nov. (Hypotrichia,Kahliellidae)

The morphology, ontogenesis, encystment, and 18S rRNA gene sequence of a new soil hypotrich ciliate, Kahliella matisi, were studied. Main characteristics of K. matisi are: (1) two short and six longitudinal cirral rows right of the adoral zone of membranelles and four longitudinal rows left of it; (2) three dorsal kineties, of which kinety 1 extends along the left cell margin, kinety 2 runs in a slightly sigmoidal line, and kinety 3 is distinctly shortened posteriorly. Ontogenesis is similar to that in congeners, especially in the development of the marginal rows and long dorsal kineties, the preservation of some old cirral rows after division, and the direction of the neokinetal wave. However, there are some peculiarities: (1) reorganization of the proximal parental adoral membranelles; (2) splitting of opisthe's anlage II into the cirral streak II and III; and (3) formation of the parental cirral row R3 from anlagen IV and V. During encystment, the body diminishes and becomes globular, the nuclear apparatus is reorganized, and the ciliature is resorbed. In our molecular phylogenies, the family Kahliellidae is polyphyletic and the position of K. matisi is rather poorly resolved, indicating a relationship with oxytrichids.