Honggang Ma

A redescription of the oxytrichid Tetmemena pustulata (Müller, 1786) Eigner, 1999 and notes on morphogenesis in the marine urostylid Metaurostylopsis salina Lei et al., 2005 (Ciliophora, Hypotrichia).

Two hypotrichous ciliates from China were investigated. The common oxytrichid species Tetmemena pustulata (Müller, 1786) Eigner, 1999, isolated from the estuary of the Pearl River in southern China, was investigated with emphasis on its living morphology and infraciliature. Tetmemena pustulata is characterized as follows: body elliptical to obovoid in shape; 75-115 × 40-60 μm in vivo; two macronuclear nodules and two micronuclei; one contractile vacuole left of midline and somewhat ahead of midbody positioned; three frontal, four frontoventral, one buccal, three postoral ventral, two pretransverse ventral and five transverse cirri; cirrus III/2 ahead of level of cirrus IV/3; cirrus IV/2 arranged more anteriorly than cirrus V/4; transverse cirri not forming two distinct groups; three prolonged and widely separated caudal cirri; six dorsal kineties in Oxytricha-pattern with dorsal kineties 3 and 4 bipolar. The marine urostylid species Metaurostylopsis salina Li et al., 2005, isolated from an aquarium in Qingdao, northern China, was investigated with emphasis on its morphogenesis which is characterized by the de novo formation of the oral primordium in the proter and the development of the marginal rows from two anlagen that form within each parental structure separately in both dividers.

Morphology, ontogeny and molecular phylogeny of a new brackish water ciliate Bakuella subtropica sp. n. (Ciliophora, Hypotricha) from southern China

This paper investigates the morphology, ontogenesis and small subunit (SSU) rRNA gene-based phylogeny of a new urostylid ciliate, Bakuella subtropica sp. n., discovered from the estuary of the Pearl River in Guangzhou, southern China. The new species is diagnosed by its elongate body, one buccal and one parabuccal cirrus, midventral complex comprised of 9-23 midventral pairs and one or two midventral rows extending to four fifths of body length, yellow-brown to yellow-greenish cortical granules and an estuary habitat. Its main ontogenetic features are: (1) in the proter, the parental adoral zone of membranelles is completely renewed by new structures and old midventral pairs join the formation of frontal-midventral-transverse cirral anlagen (FVT-anlagen); (2) in the opisthe, the oral primordium originates apokinetally, FVT-anlagen are formed besides and some old midventral cirri join the formation; (3) the anlagen for marginal rows and dorsal kineties develop intrakinetally; and (4) the numerous macronuclear nodules fuse into a single mass before dividing. Based on the SSU rDNA sequences, phylogenetic analyses show a close relationship between Bakuella subtropica sp. n., Apobakuella and Neobakuella, forming a clade separated from the other genera in the family Bakuellidae. Available morphological and ontogenetic data challenge the monophyly of Bakuellidae.

Beyond the “Code”: A Guide to the Description and Documentation of Biodiversity in Ciliated Protists (Alveolata, Ciliophora)

Recent advances in molecular technology have revolutionized research on all aspects of the biology of organisms, including ciliates, and created unprecedented opportunities for pursuing a more integrative approach to investigations of biodiversity. However, this goal is complicated by large gaps and inconsistencies that still exist in the foundation of basic information about biodiversity of ciliates. The present paper reviews issues relating to the taxonomy of ciliates and presents specific recommendations for best practice in the observation and documentation of their biodiversity. This effort stems from a workshop that explored ways to implement six Grand Challenges proposed by the International Research Coordination Network for Biodiversity of Ciliates (IRCN‐BC). As part of its commitment to strengthening the knowledge base that supports research on biodiversity of ciliates, the IRCN‐BC proposes to populate The Ciliate Guide, an online database, with biodiversity‐related data and metadata to create a resource that will facilitate accurate taxonomic identifications and promote sharing of data.

Morphology, morphogenesis and molecular phylogeny of a soil ciliate, Pseudouroleptus caudatus caudatus Hemberger, 1985 (Ciliophora, Hypotricha), from Lhalu Wetland, Tibet

Pseudouroleptus caudatus caudatus Hemberger, 1985, a soil ciliate isolated from Tibet, was studied in vivo and after protargol impregnation. The Tibetan population is mainly characterized by: elongate body with narrowly rounded anterior end and tapered posterior end; length of buccal area relative to body length ca. 20-25%; cortical granules colourless, round, densely distributed throughout sub-pellicular layer of cell; one parabuccal cirrus; post-peristomial cirrus lacking in 75% of specimens analyzed; left and right ventral rows commence at same level; four dorsal kineties; 3-6 inconspicuous caudal cirri; two macronuclear nodules; 2-7 micronuclei; contractile vacuole located at about 33% of body length near left margin. Morphogenesis is characterized by: (1) parental adoral zone of membranelles retained completely; (2) anterior segments of streaks VI and IV and the whole of streak V form the anterior, middle, posterior segments of the mixed row, respectively; (3) right ventral row originates de novo in both daughter cells; (4) marginal rows develop intrakinetally; (5) dorsal kinety anlage 3 develops de novo in the proter and intrakinetally in the opisthe; and (6) the two macronuclear nodules fuse into a single mass which then divides. Molecular phylogenies corroborate the morphological identification and support the close relationship between Pseudouroleptus and Strongylidium.

Morphology and morphogenesis of a soil ciliate, Rigidohymena candens (Kahl, 1932) Berger, 2011 (Ciliophora, Hypotricha, Oxytrichidae), with notes on its molecular phylogeny based on small-subunit rDNA sequence data.

The morphology and morphogenesis of the stylonychine hypotrich Rigidohymena candens (Kahl, 1932) Berger, 2011, isolated from garden soil in Qingdao, China, were investigated using live observation and protargol impregnation methods. The Qingdao isolate possesses all diagnostic morphological characters of R. candens. The main events during binary fission are as follows: (i) 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; (ii) five streaks of fronto-ventral-transverse cirral anlagen are segmented in the pattern 3 : 3 : 3 : 4 : 4 from left to right, which form two frontal, four frontoventral, one buccal, five ventral and five transverse cirri, respectively; (iii) dorsal morphogenesis is in the typical Oxytricha pattern; (iv) three caudal cirri are formed, one at the posterior end of each of dorsal kineties 1, 2 and 4; and (v) the postoral ventral cirrus V/3 is not involved in primordia formation. The morphological and morphogenetic observations and phylogenetic analyses based on the small-subunit rDNA sequence data support the validity of Rigidohymena Berger, 2011 and its systematic position in the subfamily Stylonychinae.

Redescriptions of Two Marine Scuticociliates from China, with Notes on Stomatogenesis in Parauronema longum (Ciliophora, Scuticociliatida)

The morphology and infraciliature of two marine scuticociliates, Pleuronema puytoraci Groliere and Detcheva, 1974, and Parauronema longum Song, 1995, collected from China, were investigated using live observation and protargol impregnation methods. Based on the data obtained for the China population, new information of the living morphology of Pleuronema puytoraci is documented and details of the complete infraciliature is available for the first time. The stomatogenesis of Parauronema longum is basically similar to that of its congeners and can be summarized as follows: membranelle 1, membranelle 2 and the scutica of the opisthe originate from the parental paroral membrane, whereas membranelle 3 of the opisthe develops from the parental scutica; the paroral membrane originates from the parental paroral membrane.

Diversity of free-living marine ciliates (Alveolata, Ciliophora): Faunal studies in coastal waters of China during the years 2011–2016

In the period 2011-2016, a series of investigations were carried out on the marine and brackish free-living ciliate fauna of the temperate-tropical coastal waters of China. About 210 morphotypes including over 100 new species within six groups (cyrtophorians, hypotrichs s.l., karyorelicteans, oligotrichs, pleurostomatids, and scuticociliates) were isolated and described in detail from observations of live cells and silver-stained specimens. Based on their morphology, morphogenesis and molecular phylogeny, three new families (Wilbertomorphidae, Kentrophyllidae, Protolitonotidae) and 22 new genera (Apotrachelocerca, Wilbertomorpha, Protolitonotus, Paracyrtophoron, Heterohartmannula, Aporthotrochilia, Falcicyclidium, Paramesanophrys, Pseudodiophrys, Monocoronella, Neourostylopsis, Apobakuella, Parabistichella, Heterokeronopsis, Heterotachysoma, Antiokeronopsis, Apoholosticha, Pseudogastrostyla, Antestrombidium, Sinistrostrombidium, Williophrya, and Varistrombidium) were established. In the present review, we summarize these studies which show there is a large, undiscovered diversity of ciliates, especially in undersampled habitats, such as subtropical/tropical coastal waters, mangrove wetlands, estuaries and aquaculture ponds. We also highlight the importance of integrative approaches, combining morphology, morphogenesis and molecular phylogeny, in order to understand ciliate systematics and ecosystem function.

Morphology, morphogenesis and small-subunit rRNA gene sequence of the novel brackish-water ciliate Strongylidium orientale sp. nov. (Ciliophora, Hypotrichia)

A novel stichotrich ciliate, Strongylidium orientale sp. nov., was discovered from a mangrove river in Hong Kong, southern China, and its morphology was investigated through observations in vivo and after protargol impregnation. Cells are 80-120 × 35-50 µm in vivo and fusiform in shape, with rounded anterior and tapered posterior ends. It is characterized by its brackish habitat and by the presence of two types of cortical granules arranged irregularly throughout the cortex. Morphogenetic events of cell division and physiological reorganization are described. The main ontogenetic features were: (i) only the posterior portion of the parental adoral zone of membranelles was renewed by dedifferentiation of the old structures; (ii) the oral primordium in the opisthe occurred apokinetally; (iii) the left and right ventral rows originated intrakinetally and the final left ventral row was spliced from two cirri from the frontoventral cirral anlage, a short cirral row from the anlage for the right ventral row and a long cirral row which was formed from the whole anlage of the left ventral row; (iv) the marginal rows developed intrakinetally; (v) the dorsal kineties replicated entirely de novo and did not fragment; and (vi) the two macronuclear nodules fused into a mass and then divided. Based on small-subunit rRNA gene sequences, phylogenetic analyses showed a close relationship with its congener Strongylidium pseudocrassum and with the genus Pseudouroleptus.

Biodiversity of marine scuticociliates (Protozoa, Ciliophora) from China: Description of seven morphotypes including a new species, Philaster sinensis spec. nov.

Seven marine scuticociliates, Philaster sinensis spec. nov., Pseudocohnilembus hargisi Evans and Thompson, 1964. J. Protozool. 11, 344, Parauronema virginianum Thompson, 1967. J. Protozool. 14, 731, Uronemella filificum (Kahl, 1931. Tierwelt. Dtl. 21, 181) Song and Wilbert, 2002. Zool. Anz. 241, 317, Cohnilembus verminus Kahl, 1931, Parauronema longum Song, 1995. J. Ocean Univ. China. 25, 461 and Glauconema trihymene Thompson, 1966. J. Protozool. 13, 393, collected from Chinese coastal waters, were investigated using live observations, silver impregnation methods, and, in the case of the new species, SSU rDNA sequencing. Philaster sinensis spec. nov. can be recognized by the combination of the following characters: body cylindrical, approximately 130-150 × 35-55 μm in vivo; apical end slightly to distinctly pointed, posterior generally rounded; 19-22 somatic kineties; M1 triangular, consisting of 13 or 14 transverse rows of kinetosomes; M2 comprising 10-12 longitudinal rows; CVP positioned at end of SK1; marine habitat. We also provide improved diagnoses for Pseudocohnilembus hargisi, Parauronema virginianum, Uronemella filificum and Parauronema longum based on their original descriptions as well as the present work. Phylogenetic analyses support the monophyly of the genus Philaster.

Morphology, Ontogeny, and Phylogeny of Two Brackish Urostylid Ciliates (Protist, Ciliophora, Hypotricha)

The diversity of hypotrichous ciliates has encouraged numerous researchers to use a combination of morphological, morphogenetic, and phylogenetic data to provide a better understanding of the evolutionary relationships within this complex group. In this study, we investigate the morphology and morphogenesis of Pseudourostyla subtropica sp. nov., isolated from mangrove wetland. The new species can be distinguished from its congeners by the huge body size, many more adoral membranelles and marginal cirral rows, and numerous macronuclear nodules. In addition, we provide a morphological characterization of a population of Pseudourostyla nova Wiackowski 1988 from an estuarine habitat. The main events during binary fission of P. subtropica sp. nov. and the Chinese population of P. nova are also revealed to be conservative. The morphological, ontogenetic, and phylogenetic analyses based on the SSU rDNA sequences corroborate the monophyly of Pseudourostyla Borror, 1972, which corresponds well with previous research. The phylogenetic analyses also show that Pseudourostyla and Hemicycliostyla Stokes, 1886, both of which are assigned to the family Pseudourostylidae based on morphological and morphogenetic data, in fact fall into separated clades. The approximately unbiased tests, however, do not reject the possibility that the family Pseudourostylidae is a monophyletic lineage.