Redefinition of the hypotrichous ciliate Uncinata, with descriptions of the morphology and phylogeny of three urostylids (Protista, Ciliophora)

Phylogeny of a new ciliate family Clampidae fam. nov. (Protista: Ciliophora), with notes on morphology and morphogenesis

Hypotrichs comprise a highly differentiated and diversified group of ciliates with an evolutionary history characterized by an exceptional number of convergences and reversions. A new hypotrich ciliate from a freshwater fishpond is investigated based on morphological, morphogenetic and molecular data. The phylogenetic analyses reveal that the new species is closely related to Simplicitergida despite the absence of zigzag-patterned midventral cirral pairs, a common feature of simplicitergids. The phylogenetic position of this atypical simplicitergid species is strongly supported by the conserved features of dorsal ciliature and nuclear apparatus, which are probably more informative than cirral patterns for higher-rank classification. The close phylogenetic relationships among those Simplicitergida with varied cirral patterns could be explained by evolutionary convergences and reversions. The new species is recognized mainly by three frontoventral rows, several short midventral rows, two long midventral rows and the absence of zigzag-patterned midventral cirral pairs. Based on comprehensive phylogenetic analyses, together with detailed morphological and morphogenetic comparisons, a new family, Clampidae fam. nov., is proposed for the new genus and species, Clampia sinica gen. et sp. nov. In addition, an emended diagnosis of the morphologically similar family Epiclintidae is provided.

Morphogenesis and molecular phylogeny of the soil ciliate Rigidohymena quadrinucleata (Dragesco and Njine, 1971) Berger, 2011 (Ciliophora, Hypotricha, Oxytrichidae)

Morphogenesis in the soil hypotrich ciliate, Rigidohymena quadrinucleata (Dragesco and Njine, 1971) Berger, 2011; was investigated using protargol staining. The main events during binary fission are as follows: (1) the proter retains the parental adoral zone of membranelles entirely, whereas the old undulating membranes dedifferentiate into an anlage that gives rise to the leftmost frontal cirrus and the new undulating membranes of the proter; (2) six streaks of frontoventral-transverse cirral anlagen are segmented in the pattern 1:3:3:3:4:4 from left to right, which form three frontal, four frontoventral, one buccal, five ventral and five transverse cirri, respectively; (3) the postoral ventral cirrus V/3 is not involved in primordia formation demonstrating that this species belongs to the stylonychines; (4) marginal anlagen are formed intrakinetally and the right marginal anlagen develop much earlier than the left ones; (5) the generation of the dorsal kineties is of typical Oxytricha-pattern and three caudal cirri are formed, one at the posterior end of each of dorsal kineties 1, 2 and 4. Phylogenetic analyses based on SSU rDNA sequence data indicate that Rigidohymena is polyphyletic and that R. quadrinucleata clusters with R. candens with full support.

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.

Morphology, morphogenesis and molecular phylogeny of a novel saline soil ciliate, Lamtostyla salina n. sp. (Ciliophora, Hypotricha)

The morphology and morphogenesis of a new saline soil hypotrich, Lamtostyla salina n. sp., collected from Longfeng Wetland in Daqing, north China, were studied based on live observations and protargol stained specimens. The new species is characterized as follows: body very flexible but not contractile, lanceolate with anterior end broadly rounded, widest at about 1/3 of body length, posterior end narrowly rounded; cortical granules colourless and scattered; amphisiellid median cirral row ends ahead of mid-body, composed of 5-13 cirri; 4-20 frontoventral cirri arranged in 2-4 rows; three frontal, one buccal and 2-6 transverse cirri; usually one left and one right marginal row, composed of 17-51 and 20-51 cirri respectively; usually two dorsal kineties; two macronuclear nodules and two micronuclei. Morphogenesis is typical of the genus Lamtostyla: parental structures are involved in the formation of frontoventral transverse anlagen in the proter. Phylogenetic analyses based on small subunit ribosomal DNA sequence data reveal that the systematic position of Lamtostyla is rather unstable with low support values across the tree. However, a well-recognized close relationship between Lamtostyla and Bistichella are shown in all phylogenetic analyses.

Morphology of four cyrtophorian ciliates (Protozoa, Ciliophora) from Yangtze Delta, China, with notes on the phylogeny of the genus Phascolodon

The morphology of four cyrtophorian ciliates, Dysteria ovalis, D. semilunaris, Phascolodon vorticella, and Chlamydonellopsis calkinsi, were investigated using living observation and protargol-staining. The morphology of D. ovalis is revealed in detail for the first time, and it is characterized by the following combination of features: size 40-50×20-30μm in vivo; oval in outline; four right kineties, including two frontoventral kineties and one shortened leftmost right kinety; three left frontal kineties; two ventrally located contractile vacuoles; marine habitat. New Chinese populations of three other species correspond well with previous descriptions, but a well-developed alveolar layer on the cell surface of P. vorticella is reported for the first time. Phylogenetic analyses based on small subunit rRNA gene sequences clustered Dysteria ovalis with Mirodysteria decora, whereas D. semilunaris is grouped with D. lanceolata. Although Phascolodon appeared as sister to Pseudochilodonopsis in the present work, its accurate phylogenetic position is still uncertain because AU test did not reject the possibility that it clustered with Odontochlamys and Chilodonella.