115 research outputs found

    Redefinition and Reassignment of the 18-cirri Genera Hemigastrostyla, Oxytricha, Urosomoida, and Actinotricha (Ciliophora, Hypotricha), and Description of One New Genus and Two New Species

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    The morphology, the infraciliature, and two stages of physiological reorganization of Hemigastrostyla elongata spec. nov.,isolated from the Yellow Sea near Qingdao (China), are described. The new species differs from the type H. stenocephala, inter alia, by the length of the dorsal bristles and the position of the pretransverse ventral cirri; from H. enigmatica by the number of caudal cirri; and from H. para-enigmatica spec. nov. – established for the H. enigmatica populations from the Yellow Sea – by the arrangement of the postoral ventral cirri and the cortical granulation. A key to the Hemigastrostyla species and some other 18-cirri hypotrichs is provided. Hemigastrostyla szaboi is fixed as type species of Heterooxytricha gen. nov. because the type population lacks the extra cirri which are characteristic for Hemigastrostyla. In addition, Oxytricha geleii is assigned to this new genus, whose species have, like many oxytrichids, 18 frontal-ventraltransverse cirri, but a Gonostomum dorsal kinety pattern. The old, large, and difficult genus Oxytricha is briefly reviewed, mainly on the basis of the dorsal kinety pattern. Very likely, only species with the Oxytricha pattern belong to this genus. Oxytricha marcili and O. pseudofurcata, which have the Urosomoida kinety pattern (i.e. kinety 3 fragmentation lacking), are transferred to Urosomoida which is, inter alia, defined by a more or less distinctly reduced number of ventral and transverse cirri. Some other Oxytricha species with this kinety pattern (O. islandica, O. lanceolata, O. pseudosimilis, O. setigera) are not transferred to Urosomoida, but preliminarily classified as incertae sedis in Oxytricha, because they have the full set of 18 cirri. The available molecular data on O. lanceolata indicate that this type of 18-cirri hypotrichs likely needs a genus of its own because O. lanceolata does not cluster with O. granulifera, type of this genus. The marine Actinotricha saltans, classified for a very long time in Oxytricha, seems to be a non-dorsomarginalian hypotrich according to molecular data, justifying the reactivation of the old genus Actinotricha. Oxytricha shii has a multiple dorsal kinety 3 fragmentation, three dorsomarginal rows, and the undulating membranes arranged in the Cyrtohymena pattern, strongly indicating that it is a member of the subgenus Cyrtohymena (Cyrtohymenides). This brief review is a further step to unravel the complicated systematics of the old, but still little-known genus Oxytricha. The following new combinations are made in this paper: Cyrtohymena (Cyrtohymenides) shii (Shi et al., 1997) comb. nov.; Heterooxytricha szaboi (Wilbert and Song, 2005) comb. nov.; Heterooxytricha geleii (Wilbert, 1986) comb. nov.; Urosomoida marcili (Paiva and Silva-Neto, 2004) comb. nov.; Urosomoida pseudofurcata (Berger, 1999) comb. nov

    Taxonomic Studies on Three Marine Ciliates from China, Including a New Species (Ciliophora, Cyrtophorida)

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    The present work investigates the living morphology and infraciliature of three marine cyrtophorid ciliates, which were isolated from Qingdao, China. Compared with its congeners, Orthotrochilia sinica spec. nov. can be distinguished by a combination of features: body slender and elliptical in outline, size about 50–60 × 20–25 μm in vivo, 18–21 somatic kineties, the length of the left perioral kinety treble the length of the right one, two ventrally located contractile vacuoles on the right side, and 25–32 nematodesmal rods. Based on current observations and the previous description, the diagnosis of Trochilioides tenuis (Deroux, 1976) Chen et al. 2011 is improved: cell size 30–40 × 20–35 μm in vivo, oval shaped in outline; consistently three right kineties, four left kineties and seven postoral kineties; a single contractile vacuole; marine habitat. A second species of Trochilioides, T. recta (Kahl, 1923) Chen et al. 2011 is re-described based on a Chinese population. Furthermore, a key to the identification of species of the genus Trochilioides whose infraciliature data are available is supplied, and Chlamydonyx trivialis (Fenchel, 1965) comb. nov. [basionym: Trochilioides trivialis Fenchel, 1965] is suggested

    The Diversity of Scuticociliates (Protozoa, Ciliophora): A Report on Eight Marine Forms Found in Coastal Waters of China, with a Description of One New Species

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    Eight marine scuticociliates, Pseudoplatynematum denticulatum (Kahl, 1933) nov. comb., Protocyclidium sinica nov. spec., Histiobalantium marinum Kahl, 1933, Porpostoma notata Möbius, 1888, Philaster hiatti Thompson, 1969, Parauronema longum Song, 1995, Uronemella parafilificum Gong et al., 2007, and Paranophrys magna Borror, 1972, collected from Chinese coastal waters, were investigated using live observations and silver impregnation methods. Investigations of a Chinese population of Platynematum denticulatum (Kahl, 1933) reveal that it has a highly strengthened pellicle and distinct spines and thus corresponds well with the definition of Pseudoplatynematum Bock, 1952. A new combination, Pseudoplatynematum denticulatum (Kahl, 1933) nov. comb., is therefore proposed and an improved species diagnosis is supplied. Protocyclidium sinica nov. spec. is characterized by: small body size with buccal field approximately 60% of body length; extrusomes present; 13 or 14 somatic kineties; somatic kinety 1 comprising approximately 24 densely arranged kinetids; somatic kinety n shortened posteriorly; single macronucleus. Additional information is documented on the morphology of six other species of scuticociliates based on the China populations

    A Morphogenetic Description of Thigmokeronopsis stoecki Shao et al., 2008 (Ciliophora, Hypotricha) and a Comparison with Members of the Family Pseudokeronopsidae

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    The urostylid family Pseudokeronopsidae Borror and Wicklow, 1983 was considered to be a well-outlined taxon. Nevertheless, recent evidence, including morphological, ontogenetic, and molecular information, has consistently revealed the polyphyly of this family. In the present work, a new population of Thigmokeronopsis stoecki Shao et al., 2008 was found and its binary divisional process was described for the first time. In addition, the morphogenetic features of Thigmokeronopsis species and all the other pseudokeronopsids, for which detailed ontogenetic data are available, were rechecked and compared. This reveals that: (1) the ontogenetic process of T. stoecki corresponds well with its congeners T. jahodai and T. rubra except for the macronuclear behavior; (2) Apokeronopsis and Thigmokeronopsis share a similar ontogenetic mode despite of the differences in the number and origin of their buccal cirri; (3) most pseudokeronopsids share the same pattern in the origins of their oral primordia and fronto-ventral-transverse cirral anlagen, except for Pseudokeronopsis similis, which may not be a valid member of the family Pseudokeronopsidae

    Déclin précipité du Triton de Poiret Pleurodeles poireti Gervais, 1835 et autres changements du statut des amphibiens de Numidie, Algérie du Nord-Est

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    The worldwide erosion of biological diversity has not spared amphibians which are amongst the most affected taxa with numerous extinct or near-extinct species. Our knowledge of the status and ecology of amphibians of Algeria is still limited whereas local natural habitats are fast disappearing under a strong anthropogenic pressure. Eighty two localities were sampled between 1996 and 2010, to survey the amphibian community within Numidia, North-Eastern Algeria. Nine species, three Urodeles (Pleurodeles poireti, Pleurodeles nebulosus and Salamandra algira and six Anurans (Bufo bufo spinosus, Bufo mauritanicus, Bufo viridis, Discoglossus pictus, Hyla meridionalis and Pelophylax saharicus) were found within the region. Results suggest a marked, rapid and unexplained crash of the Algerian Newt Pleurodeles poireti, a species endemic to a small area in and around Djebel Edough (Annaba). Information on the status (abundance and distribution) of each recorded taxon is provided and conservation measures are discussed in the light of an apparent local decline of Anurans and the vulnerability of three species (S. algira, P. nebulosus and B. bufo spinosus)La crise aiguë que traverse la biodiversité à l'échelle planétaire n'a pas épargné les amphibiens qui figurent parmi les taxons les plus touchés, illustrés par le déclin prononcé ou la disparition de plusieurs espèces. Notre connaissance du statut et de l'écologie des amphibiens d'Algérie reste limitée alors que les milieux naturels locaux subissent une pression anthropique intense qui ne fait que s'accroître et qui risque de s'exacerber sous l'effet du réchauffement climatique. Dans le but d'inventorier et d'évaluer le statut du peuplement d'amphibiens du complexe de zones humides de la Numidie, «point chaud» pour de nombreux taxons aquatiques et poche relictuelle afrotropicale, nous avons échantillonné 82 sites entre 1996 et 2010. Un total de neuf espèces dont trois Urodèles (Pleurodeles poireti Gervais, 1835, Pleurodeles nebulosus (Guichenot, 1850) et Salamandra algira Bedriaga, 1883) et six Anoures (Bufo bufo spinosus, Bufo mauritanicus Schlegel, 1841, Bufo viridis Laurenti, 1768, Discoglossus picrus Otth, 1837, HYla meridionalis Boettger, 1874 et Pelophylax saharicus Boulanger in Hartert, 1913) ont été inventoriées. Un fait marquant est le déclin net, rapide et inexpliqué du Triton de Poiret Pleurodeles poireti, espèce endémique à une région limitée au Djebel Edough et ses environs, au cours des dernières années. Le statut de trois espèces (S. algira, P. nebulosus and B. bufo spinosus) semble préoccupant au vu des pressions anthropogéniques qui s'exercent sur la Numidie qui abrite 82% des amphibiens d'Algérie

    Morphology and SSU rRNA Gene Sequences of Three Marine Ciliates from Yellow Sea, China, Including One New Species, Uronema heteromarinum nov. spec. (Ciliophora, Scuticociliatida)

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    The morphology, infraciliature, and silverline system of three marine scuticociliates, Uronema marinum Dujardin, 1841, U. heteromarinum nov. spec. and Pleuronema setigerum Calkins, 1902, isolated from coastal waters off Qingdao, China, were investigated using living observation and silver impregnation methods. Due to the great confusion in the species definition of the well-known species U. marinum, we have documented a detailed discussion/comparison and believe that most of the confusion is due to the fact that at least 2 closely-related sibling morphotypes exist which are often not recognized. Based on the data available, U. marinum is strictly defined as follows: marine Uronema ca. 30 × 10 μm in size, with truncated apical frontal plate and smooth pellicle, extrusomes inconspicuous, cytostome located equatorially, 12–14 somatic kineties and one contractile vacuole pore near posterior end of kinety 2. Uronema heteromarinum nov. spec. resembles U. marinum but can be distinguished morphologically by its notched pellicle with conspicuous extrusomes and reticulate ridges, the 15–16 somatic kineties, widely separated membranelle 1 and membranelle 2, as well as the subequatorially positioned cytostome. Based on the Qingdao population, an improved diagnosis for the poorly known Pleuronema setigerum is: marine slender oval-shaped form, in vivo about 40–50 × 15–20 μm; 3–5 preoral kineties and 14–22 somatic kineties; membranelle 1 and 3 three-rowed, and posterior end of M2a ring-like. The small subunit (SSU) rRNA gene for all three organisms were sequenced and analyzed with standard methods

    Morphological and Morphogenetic Redescriptions and SSU rRNA Gene-based Phylogeny of the Poorly-known Species Euplotes amieti Dragesco, 1970 (Ciliophora, Euplotida)

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    This paper investigates the morphology and morphogenesis during binary fission of a Chinese population of Euplotes amieti Dragesco, 1970, a fresh water form which has previously not been well defined. This organism is morphologically very similar to the well-known Euplotes eurystomus but differs from the latter both in the number of dorsal kineties and the molecular data. According to the information obtained, it is characterized by a combination of features including nine frontoventral cirri, ca. 60 membranelles, 12–15 dorsal kineties, a macronucleus in the shape of the number 3, and a ‘double-eurystomus’ type of silverline system. Its morphogenesis proceeds broadly in the same pattern as in its congeners. In this study, the SSU rRNA gene was sequenced for the first time, and phylogenetic analyses indicated that it is closely related to the eurystomus-aediculatus-woodruffi- complex. Considering the extreme similarities in morphology between E. amieti and E.eurystomus, we believe that the four sequences (four isolates) under the name of Euplotes eurystomus (No. FR873716; FR873717; EF193250; AJ310491 deposited in GenBank) are very likely from misidentified material; that is, they represent different populations of Euplotes amieti

    Taxonomic Descriptions of Two Marine Ciliates, Euplotes dammamensis n. sp. and Euplotes balteatus (Dujardin, 1841) Kahl, 1932 (Ciliophora, Spirotrichea, Euplotida), Collected from the Arabian Gulf, Saudi Arabia

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    The morphology, morphogenesis and infraciliature of two marine euplotid ciliates, Euplotes dammamensis n. sp. and Euplotes balteatus (Dujardin, 1841) Kahl, 1932, isolated from a sandy beach of the Arabian Gulf, Saudi Arabia, were investigated using observations in vivo and protargol-impregnation methods. Euplotes dammamensis n. sp. is characterized by a combination of features including its huge body size (100–170 × 80–120 μm), 10 conspicuous dorsal ridges, 10 normal-sized frontoventral and two marginal cirri, and 11 dorsal kineties. Euplotes balteatus is mainly characterized by 10 frontoventral, two caudal, and two left marginal cirri, 7–10 dorsal kineties and 5–7 prominent dorsal ridges as well as double-eurystomus silverline system. The small subunit rRNA (SSU-rRNA) gene sequences were determined for both species and phylogenetic analyses based on these data indicated that E. dammamensis is most closely related to E. parabalteatus Jiang et al., 2010, and E. balteatus clusters with E. plicatum Valbonesi et al., 1997, E. orientalis Jiang et al., 2010, and E. bisulcatus Kahl, 1932

    Apogastrostyla rigescens (Kahl, 1932) gen. nov., comb. nov. (Ciliophora, Hypotricha): Morphology, Notes on Cell Division, SSU rRNA Gene Sequence Data, and Neotypification

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    The morphology, the infraciliature, some stages of cell division and physiological reorganization, and the SSU rRNA gene sequence of the little-known marine 18-cirri hypotrich Tachysoma rigescens (Kahl, 1932) Borror, 1972 [basionym Oxytricha (Tachysoma) rigescens], isolated from mariculture waters near Qingdao, China, were investigated. This rare species is characterized, inter alia, by narrowly spaced, small, colourless cortical granules and several conspicuous ring-shaped structures in the cytoplasm. The caudal cirri and the simple dorsal kinety pattern (three bipolar kineties) are probably plesiomorphic traits within the Hypotricha, the composition of the adoral zone of the proter from new and parental membranelles, as well as the presence of two ‘extra’ cirri behind the right marginal row strongly suggest a misclassification in Tachysoma. The SSU rRNA gene sequence data indicate that T. rigescens branches off rather basally in the Hypotricha tree, which supports the hypothesis that the 18-cirri pattern occurred very early, probably already in the last common ancestor of the Hypotricha. A detailed survey of the early branching 18-cirri hypotrichs and similar taxa (e.g. Trachelostyla pediculiformis, Hemigastrostyla enigmatica, Protogastrostyla pulchra) reveals that for T. rigescens a new genus (Apogastrostyla gen. nov.) has to be established, because there are important differences, inter alia, in the dorsal infraciliature. Besides the type species, A. rigescens comb. nov., which seems to be confined to the northern hemisphere according to the sparse faunistic data, a second marine species, A. szaboi comb. nov. (basionym Hemigastrostyla szaboi), so far only twice recorded from the Antarctic region, can be included. The Chinese population is fixed as neotype to define the species objectively, because no type material of A. rigescens is present and the original type locality is not known. The species name Tachysoma multinucleate is emended: Tachysoma multinucleatum nom. corr

    Guard Cell-Specific Calcium Sensitivity of High Density and Activity SV/TPC1 Channels

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    The slow vacuolar (SV) channel, a Ca2+-regulated vacuolar cation conductance channel, in Arabidopsis thaliana is encoded by the single-copy gene AtTPC1. Although loss-of-function tpc1 mutants were reported to exhibit a stoma phenotype, knowledge about the underlying guard cell-specific features of SV/TPC1 channels is still lacking. Here we demonstrate that TPC1 transcripts and SV current density in guard cells were much more pronounced than in mesophyll cells. Furthermore, the SV channel in motor cells exhibited a higher cytosolic Ca2+ sensitivity than in mesophyll cells. These distinct features of the guard cell SV channel therefore probably account for the published stomatal phenotype of tpc1-
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