The Cortical Morphogenetic Cycle Associated with Cell Division in Diophrys Dujardin, 1841 (Ciliophora,Hypotrichida)1

Morphogenesis of cell division was investigated in Diophrys scutum, D. oligothrix, and D. appendiculata utilizing both light microscopy of living and stained specimens and SEM of preserved specimens. The cortical morphogenetic pattern of Diophrys is similar to that of other members of the family Euplotidae. The opisthe oral primordium, which develops in a subsurface pouch, forms posterior to the parental buccal cavity. The proter inherits the parental adoral zone of membranelles (AZM) apparently unchanged. The endoral membrane forms to the right of the posterior end of the AZM in the proter, in association with the developing AZM in the opisthe. The paroral cirrus and membrane develop from a single streak that first appears along the right edge of the buccal cavity in the proter to the right of the developing buccal structures of the opisthe. Frontal and transverse cirri develop in both proter and opisthe from five separate cirral primordia that form to the right of the buccal cavity. Left marginal cirri do not develop in association with the corresponding parental structures. Kinetosomes formed within the opisthe oral primordium, or kinetosomes that were part of any parental ciliary structure, do not appear to become part of any developing paroral structures, frontal, transverse, or left marginal cirri. Speciation within the genus Diophrys and evolution of the family Euplotidae as they relate to the morphogenesis of cortical structure are discussed.     

Morphologie und Morphogenese des Bodenciliaten Oxytricha granulifera sp.n. (CiIiophora, Oxytrichidae)

Oxytricha granulifera sp.n. differs from other members of the genus by its subpellicular granules and the strongly shortened dorsal kinety 4. The overall pattern of the morphogenetic events is similar to that known from other Oxytrichidae. However, the oral primordium evolves de novo between the left marginal cirral row and the postoral cirri. The six anlagen of the frontoventral cirri are of different origin. Two anlagen of the proter evolve from parental frontal cirri, two from the opisthe, and one includes basal bodies of the proter and opisthe. Two anlagen of the opisthe evolve from the oral primordium, and three primordia originate from the postoral cirri. Frontal cirrus 1 evolves from the paroral membrane in the proter, and from the oral primordium and the anlagen of the frontoventral cirri in the opisthe. The genus Oxytricha can be subdivided into several groups with regard to the origin of its oral primordium and the development of the frontoventral cirri. The morphogenesis of the dorsal kineties in the Hypotrichida is reviewed. Seven different modes of origin are distinguished. We conclude that morphogenetic features cannot be used in the classification of the Hypotrichida at the generic level, because we have too little information to decide whether special morphogenetic features are important at the generic or species level.     

Morphogenesis of a unique pseudourostylid ciliate,Trichototaxis songi (Ciliophora,Urostylida)

Divisional morphogenesis in the freshwater spirotrichous ciliate, Trichototaxis songi Chen et al., 2007, was investigated. The main morphogenetic events are characterised as follows: (1) the parental oral apparatus is completely renewed by the independently formed oral primordium in the proter; (2) the oral primordium in the opisthe is formed on the cell surface; (3) several left cirri of the midventral pairs participate in the formation of the oral primordium in the opisthe; (4) FVT-anlage I forms the leftmost pair of the bicorona; (5) the macronuclear nodules fuse into many masses rather than a single or branched mass as described in most pseudokeronopsids; and (6) usually, two marginal anlagen develop within each left marginal row separately. However, the number of left marginal anlagen is highly variable, even differing between the proter and opisthe of the same divider. The increase in the number of left marginal anlagen is by de novo generation of small anlagen to the left of the intrakinetal left marginal anlage, whereas the decrease in number is by resorption of the old marginal row(s). We posit that Trichototaxis is an intermediate form between the Pseudourostylidae and Pseudokeronopsidae as it shares morphogenetic features with both. Additionally, as in Uroleptopsis (Uroleptopsis), FVT-anlage I forms the leftmost pair of the bicorona in Trichototaxis indicating these genera may be closely related.     

Description of the Rare Marine Ciliate, Uronychia multicirrus Song, 1997 (Ciliophora; Euplotida) based on Morphology, Morphogenesis and SS rRNA Gene Sequence

ABSTRACT. A population of the marine euplotid ciliate, Uronychia multicirru s Song 1997 , found in the littoral zone of the Daya Bay, Guangdong, South China, was investigated using live observation and protargol impregnation method. This species is diagnosed by possessing a long row of ventral cirri, which has never been seen in all other known congeners. Divisional process, described based on protargol-impregnated specimens, is typical of the genus regarding its general pattern: (1) the oral primordia in both proter and opisthe develop de novo in two subcortical pouches, while the UM-anlage forms de novo (i.e. does not develop from the oral primordium); (2) five frontoventral-transverse (FVT)-cirral anlagen develop in a primary-mode on the cell surface, and almost all the cirri are derived from the FVT-anlagen, except the first frontal cirri, which are formed de novo in both dividers; (3) the species characteristic ventral row derives from the right-most FVT-anlage; (4) the parental structures do not take part in the construction of the marginal anlagen, and (5) the caudal cirri originate in the right-most two dorsal kineties in a multi-segmentation mode. The small subunit rRNA gene of U. multicirrus (GenBank accession number: EU267929) is 1,773 bp and differs by 0.9–1.41% from its closely related congeners.     

Morphological,Biometric, and Morphogenetic Comparison of Two Closely Related Species,Stylonychia vorax and S. pustulata (Ciliophora: Oxytrichidae)1

Differences in the morphology of Stylonychia vorax Stokes, 1885 and S. pustulata (Müller, 1786) Ehrenberg, 1838 recognizable in vivo are the shape, the ventral cirral pattern, the caudal cirri, and the mode of moving. The dorsal-bristle complexes are distinguishable by the length of dorsal kinety four and the spaces among the pairs of basal bodies. When the ranges of variation of different populations and clones are compared by biometric analyses, S. vorax shows a relatively stable cortical pattern whereas in S. pustulata the cortical elements are regulated depending on the size of the body and the number of adoral membranelles. In S. vorax morphogenesis begins with a proliferation of basal bodies close to the transverse cirri. In contrast, in S. pustulata, the oral primordium appears de novo between the left marginal row and the postoral cirri. All other morphogenetic events are the same for both species. In proters and opisthes the six anlagen of the frontal-ventral-transverse cirri are of different origin and evolve independently. Three anlagen of the opisthe separate from the oral primordium, two originate from the right, and one from the left postoral cirrus. Three anlagen of the proter evolve from the posteriormost cirrus in the frontal area, one from the parental undulating membranes, one from the buccal cirrus, and one from the cirrus below the buccal cirrus. The anlagen one to six generate one, three, three, three, four, and four cirri. The characteristic arrangement of the undulating membranes and the participation of only two postoral cirri in the formation of primordia provide features that distinguish between the often confused genera Oxytricha and Stylonychia.     

Morphogenesis of the marine spirotrichous ciliate, Trachelostyla pediculiformis (Cohn, 1866) (Ciliophora, Stichotrichia), with consideration of its phylogenetic position

The cortical development during binary fission of the relatively poorly known stichotrich ciliate, Trachelostyla pediculiformis (Cohn, 1866) Borror, 1972, found in coastal waters near Qingdao, China, was investigated using the protargol impregnation method. The morphogenetic process reveals some pretty unusual characteristics, which do not follow the Oxytricha-pattern: (1) the parental oral apparatus is entirely renewed from an oral primordium formed de novo in the proter; (2) in the proter, the parental undulating membranes are not involved in the formation of the newly formed oral primordium; both undulating membrane-anlagen (UM-anlage) and frontoventral-transverse cirral anlagen (FVT-anlagen) develop from the oral primordium in the proter; (3) the dorsal kineties (DK) are generated in a unique way, that is, in both dividers, two separate groups of DK-anlagen develop in the right- and left-most DK, generate all the DK and evolve to replace the old structures; (4) three caudal cirri are formed at the posterior ends of three right-most dorsal kinety anlagen; (5) eight frontal, five ventral and five transverse cirri are derived from six streaks, namely, the UM-anlage and 5 FVT-anlagen; the cirri are segregated from these anlagen in the pattern 1:3:3:3:4:4 (from left to right) in the Oxytricha mode. Based on both SSrRNA gene sequencing and morphogenetic data, the systematic positions of the genus Trachelostyla Borror, 1972 as well as the family Trachelostylidae Small and Lynn, 1985 are briefly analyzed. The results indicate that this genus/family could be a highly isolated lineage and might be ancestral to other well-known oxytrichids.     

Morphogenesis of the marine ciliate, Pseudoamphisiella alveolata (Kahl, 1932) Song & Warren, 2000 (Ciliophora, Stichotrichia, Urostylida) during binary fission

Morphogenesis during the binary fission of the stichotrich ciliate Pseudoamphisiella alveolata, isolated from Jiaozhou Bay near Qingdao, China, was investigated using protargol silver impregnation. The process is characterized as follows: (1) in the proter, only the posterior part of the parental adoral zone of membranelles is renewed, where the membranelles dedifferentiate and then rebuild the UM-anlage and the missing membranelles, (2) the oral primordium in the opisthe and the FVT-anlagen in both dividers are formed de novo on the cell surface, (3) an "extra" anlage, which is generated on the right of the right marginal anlage, develops into three or four "extra" marginal cirri that connect the caudal cirri with the marginal rows, (4) the right marginal anlage is formed within the old structure, (5) the FVT-cirri develop in a primary mode, and (6) unlike most stichotrichs, the right marginal anlagen in both dividers generate closely together. As an additional contribution, the diversity of morphogenetic patterns within the genus Pseudoamphisiella is discussed. Based on both morphogenetic and SS rRNA gene sequencing data, the systematic position of the genus Pseudoamphisiella as well as the family Pseudoamphisiellidae Song et al. 1997 is briefly analyzed. The results indicate that they should very possibly represent a higher evolved group in the order Urostylida.     

Morphology and Morphogenesis of a Novel Saline Soil Hypotrichous Ciliate,Gonostomum sinicum nov. spec. (Ciliophora,Hypotrichia, Gonostomatidae), Including a Report on the Small Subunit rDNA Sequence

Morphology, cirral pattern, and morphogenesis of the new saline soil hypotrich, Gonostomum sinicum nov. spec. collected from Longfeng Wetland in Daqing, north China, were studied, using detailed live observations and protargol‐stained specimens. The new species is characterized as follows: (i) a size in vivo of 100–125 × 30–40 μm, (ii) colorless cortical granules, 0.5 μm across, arranged in short rows, (iii) an adoral zone composed of 28–33 membranelles, (iv) three or four frontoventral rows, one of which extends onto the postoral area, (v) left and right marginal rows composed of 18–27 and 21–35, cirri, respectively, and (vi) usually two transverse cirri. Morphogenesis is as usual for the genus Gonostomum, i.e. the cirral primordia II–VI are primary primordia which split into two sets for proter and opisthe in division middle stages, except for anlage I which develops independently. However, the number of frontoventral transverse anlagen is either five or six not only in different individuals but even in proter and opisthe of the same divider. The phylogenetic analyses based on SSU rDNA sequences showed that the genus Gonostomum is nonmonophyletic, indicating that the patterns of cirri and dorsal kineties are homoplasious characters. The new species G. sinicum nov. spec. is perhaps closely related to Cotterillia bromelicola and two congeners.