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.     

The Taxonomy and Phylogeny of the Poorly known Heterotrich Ciliate Ampullofolliculina lageniformis Hadži, 1951 (Ciliophora: Heterotrichea)

Ampullofolliculina Had?i, 1951 is a monotypic genus, the only species being A. lageniformis which was first discovered in estuarine habitats in the U.S. and has never been redescribed. In the present study, we investigated the taxonomy and phylogeny of A. lageniformis Had?i, 1951 based on analyses of a population collected from a brackish wetland in Ningbo, China. The main characteristics of this species are as follows: trophont about 450–700 μm long in vivo with two short, rounded peristomial lobes of equal size; lorica flask‐shaped, transparent and smooth with a short, wide neck at the base of which two transparent valves are asymmetrically inserted; cortex with brownish to reddish cortical granules and greenish pigment granules; about 80 somatic kineties evenly arranged; moniliform macronucleus with 4–8 ellipsoidal nodules; swarmer dark green, vermiform in shape, about 200–350 μm long in vivo, with about 60 adoral membranelles and 85 somatic kineties, no mouth nor paroral membrane. Phylogenetic analyses inferred from SSU rDNA sequences show that A. lageniformis is closely related to Folliculina and Eufolliculina which nest within a large clade that comprises five families, i.e. Stentoridae, Blepharismidae, Fabreidae, Maristentoridae, and Folliculinidae.     

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.     

Morphology and Phylogenetic Position of an Unusual Stentor polymorphus (Ciliophora: Heterotrichea) Without Symbiotic Algae

We investigated the live morphology, infraciliature, and small subunit rRNA gene sequences of an unusual population of Stentor polymorphus without symbiotic algae that was isolated from the southeastern region of Brazil. The morphological and molecular data confirmed the identity of this strain as S. polymorphus. The Brazilian S. polymorphus organism is 850–2,000 μm in length in vivo and has colorless cortical granules, a moniliform macronucleus with 6–12 nodules, somatic ciliature composed of 50–60 kineties, a single contractile vacuole located to the left of the cytostome, and a conspicuous oral pouch, and it does not build a lorica. Based on the phylogenetic analyses, the Brazilian S. polymorphus was located within a cluster consisting of four other S. polymorphus sequences, with high support values using both the Bayesian inference and maximum likelihood algorithms. Our study presents the first report of a S. polymorphus population without its symbionts under natural conditions. On the basis of our findings, we propose that the presence or absence of symbiotic algae should not be used as a taxonomic character for the identification of Stentor species.     

Reconciling cladistic and genetic analyses in choreotrichid ciliates (Ciliophora, Spirotricha, Oligotrichea)

Fifty-six features of halteriid, oligotrichid, and choreotrichid ciliates are cladistically analysed, including an updated hypothesis about the evolution of the somatic ciliary patterns. Based on its morphology, Lynnella clusters with Parastrombidinopsis, Parastrombidium, and Strombidinopsis, while it is basal to the other choreotrichids in the molecular phylogenies. The two clusters of Favella species in small subunit rRNA gene trees are supported by morphological features, justifying a separation at genus and family level. The genus Favella has a smooth lorica surface and a somatic ciliary pattern comprising a left and lateral ciliary field as well as two dorsal kineties and a monokinetidal ventral kinety abutting on the right ciliary field. The new genus Schmidingerella n. gen., established for the second Favella cluster, groups with Metacylis and Rhabdonella in the molecular trees. It differs from Favella in (i) a lorica wall with reticulate surface ridges and minute openings and (ii) a ventral kinety that is distinctly apart from the right ciliary field and composed of a monokinetidal anterior and a dikinetidal posterior portion. The genera Codonaria, Codonella, and Codonellopsis are affiliated with the family Dictyocystidae, whose diagnosis is improved to include the lorica sac.     

Morphological and Molecular Description of Three New Species of the Cyrtophorid Genus Chlamydodon (Ciliophora,Cyrtophoria)

This study investigates the morphology and molecular characteristics of three new cyrtophorid ciliates isolated from China seas: Chlamydodon salinus n. sp., Chlamydodon caudatus n. sp., and Chlamydodon paramnemosyne n. sp. Of these, C. salinus n. sp. differs from its congeners through a combination of body size, a cross‐striated band that is not continuous, the presence of 30–34 somatic kineties, 11–15 nematodesmal rods, and 13 contractile vacuoles. Chlamydodon caudatus n. sp., meanwhile, is characterized by having a conspicuous tail, a continuous cross‐striated band, 34–40 somatic kineties, about 15 contractile vacuoles, and 20–24 nematodesmal rods. Compared with other Chlamydodon species, the third new one, C. paramnemosyne n. sp., could be identified by its continuous cross‐striated band, 16–18 somatic kineties, 5 contractile vacuoles, and 9–12 nematodesmal rods. Based on the sequence of the small subunit (SSU) rRNA gene, the phylogeny of these three new species was analyzed, indicating that they all clustered with other congeners to form a monophyletic assemblage. Based on previous studies and the present work, a brief revision of the genus Chlamydodon is supplied, and a key to aid the identification of Chlamydodon species is given.     

Three new entocommensal ciliates from digestive tract of sea urchins of the Weddell Sea,Antarctica (Protozoa,Ciliophora)

Three new entocommensal ciliates (Spirostrombidium echini sp. nov., Entodiscus pseudoechini sp. nov. and Cryptochilum antarcticum sp. nov.) from the digestive tract of sea urchins in Antarctica (Weddell Sea) were studied using protargol and silver nitrate impregnation methods. Based on our reinvestigations, improved diagnoses for the genera Entodiscus and Cryptochilum are provided. According to the general morphology, E. pseudoechini is recognized by a higher number of ciliary rows, the absence of a caudal cilium which is typically present for other congeners, and shortened somatic kineties direct to the ventral surface, of which the last somatic kinety does not pass through the caudal pole as in most other scuticociliates. C. antarcticum differs from the known congeners in its particularly high number of somatic kineties. S. echini is distinguished by the combination of habitat, body shape, structure of buccal apparatus and arrangement of somatic kineties. Accepted: 29 March 1999     

Pelagostrobilidium liui n. sp. (Ciliophora,Choreotrichida) from the Coastal Waters of Northeastern Taiwan and an Improved Description of Pelagostrobilidium minutum Liu et al., 2012

The number of somatic kineties in Pelagostrobilidium ranges from 4 to 6 according to the present state of knowledge. This study investigates Pelagostrobilidium liui n. sp. using live observation, protargol stain, and small subunit rDNA data sequencing. Pelagostrobilidium liui n. sp. is characterized by having a spherical‐shaped body, four somatic kineties, with kinety 2 spiraled around the left side of body, about six elongated external membranelles, and invariably no buccal membranelle. It differs from its most similar congener, Pelagostrobilidium minutum Liu et al., 2012 , in (i) cell shape; (ii) macronucleus width; (iii) oral apparatus; (iv) anterior orientation of kinety 2; (v) location where kinety 2 commences; (vi) arrangement of kinety 1; (vii) distance between the anterior cell end and the locations where kineties commence; and (viii) the presence of 12 different bases (including two deletions) in the small subunit rDNA sequences. The diagnosis of P. minutum Liu et al., 2012 is also improved to include the following new characteristics: invariably four somatic kineties; kineties 2 and 4 alone commence at the same level; kinety 2 originates from right anterior cell half on ventral side, extends sinistrally posteriorly, over kinety 1, around left posterior region, terminates near posterior cell end on dorsal side; kinety 1 commences below anterior third of kinety 2.     

Redescription of Parasonderia vestita () comb. nov. (Ciliophora,Plagiopylida), with notes on its phylogeny based on SSU rRNA gene

During faunistic studies on psammophilic ciliates along the coast of Qingdao, China, a population of the poorly known species Parasonderia vestita (Kahl, 1928) comb. nov. (basionym: Plagiopyla vestita Kahl, 1928) was found and investigated using silver staining methods. These revealed that its oral ciliature is rather unique and composed of polykinetids comprising four parts: prebuccal polykineties, postbuccal polykineties, parabuccal polykineties, and intrabuccal polykineties. Both the pre- and the postbuccal polykineties are, as extensions of the somatic kineties, spiraling and extending from cell surface into buccal cavity. The somatic kineties are composed mainly of dikinetids with some monokinetids and trikinetids inserted. They are separated into two types: four circle kineties and 24–28 bipolar kineties. The circle kineties start from the side of oral region and connect with the opposite section at the end of the body. Phylogenetic analysis based on SSU rRNA gene sequence data indicates that P. vestita falls into the core part of the order Plagiopylida and groups with an environmental sequence with high support and forms a sister clade with Lechriopyla mystax, Plagiopyla frontata and P. nasuta.     

Tetrahymena australis (Protozoa,Ciliophora): A Well‐Known But “Non‐Existing” Taxon – Consideration of Its Identification,Definition and Systematic Position

A cryptic species of the Tetrahymena pyriformis complex, Tetrahymena australis, has been known for a long time but never properly diagnosed based on taxonomic methods. The species name is thus invalid according to the International Code of Zoological Nomenclature. Recently, a population isolated from a freshwater lake in Wuhan, China was investigated using live observations, silver staining methods and gene sequence data. This organism can be separated from other described species of the T. pyriformis complex by its relatively small body size, the number of somatic kineties and differences in sequences of two genes, namely the small subunit ribosomal RNA (SSU rRNA) and the mitochondrial cytochrome c oxidase subunit I (cox1). We compared the SSU rRNA gene sequences of all available Tetrahymena species to reveal the nucleotide differences within this genus. The sequence of the Wuhan population is identical to two sequences of a previously isolated strain of T. australis (ATCC #30831). Phylogenetic analyses indicate that these three sequences (X56167, M98015, KT334373) cluster with Tetrahymena shanghaiensis (EF070256) in a polytomy. However, sequence divergence of the cox1 gene between the Wuhan population and another strain of T. australis (ATCC #30271) is 1.4%, suggesting that these may represent different subspecies.     

Morphology and Morphogenesis of Strobilidium caudatum (Fromentel), Meseres corlissi N. Sp., Halteria grandinella (Müller), and Strombidium rehwaldi N. Sp., and a Proposed Phylogenetic System for Oligotrich Ciliates (Protozoa,Ciliophora)1

ABSTRACT. The morphology and morphogenesis of some oligotrichs were investigated using protargol impregnation, silver carbonate impregnation and scanning electron microscopy. The somatic kineties of Strobilidium caudatum form a spiral at the posterior pole. Strobilidiids without such a spiral are transferred to the genus Rimostrombidium. Fourteen new combinations and a nomen novum, Strobilidium kahli, are necessary, Meseres corlissi n. sp. is characterized by eight somatic kineties composed of long cilia which are not fused to “bristles” as they are in Halteria. Strombidium oblongum shows similar characteristics and is thus combined with Meseres. Strombidium rehwaldi n. sp. has an anterior and an equatorial girdle of extrusomes. The morphogenesis of Meseres and Halteria is very similar, i.e. the entire somatic ciliature and the oral primordium originate apokinetally on the cell surface; the parental somatic ciliature is resorbed. In strobilidiids and tintinnids, the oral anlagen develop in a subsurface pouch and the parental somatic kineties, which are not resorbed, elongate by intrakinetal proliferation of basal bodies. In strombidiids, the oral primordium develops in an intracellular sac or tube. These morphogenetic peculiarities and distinct morphologic characters (e.g. arrangement of adoral membranelles) were applied in constructing a phylogenetic system for oligotrichs using hypotrichs as outgroup. This shows that halteriids are more closely related to hypotrichs than they are to other oligotrichs. The Halteriidae are thus raised to ordinal and subclass ranks, Halteriida n. ord., Halteriia n. subcl.     

A Contribution to the Morphology and Phylogeny of Chlamydodon,with Three New Species from China (Ciliophora,Cyrtophoria)

Three new cyrtophorian ciliates isolated from coastal areas of China were described based on morphological and genetic data. The Chlamydodon mnemosyne‐like species Chlamydodon similis sp. n. differs from its congeners mainly by its number of somatic kineties. Chlamydodon oligochaetus sp. n. is distinguished from its congeners mainly by having fewer somatic kineties, and/or an elongated body shape. Chlamydodon crassidens sp. n. is characterized mainly by an inverted triangular body shape, a posteriorly interrupted cross‐striated band (5–6 μm wide), and a large cytostome. Moreover, we provided small‐subunit (SSU) rDNA sequences of C. similis sp. n. and C. oligochaetus sp. n. Maximum likelihood (ML) and Bayesian inference (BI) consistently placed C. similis sp. n. as a sister to C. paramnemosyne, but showed different branching position of C. oligochaetus sp. n., which may be due to a low taxon sampling in the Chlamydodontidae and/or an insufficient resolution of the marker gene at species level.     

Morphology of Three Species of Amphileptus (Protozoa,Ciliophora, Pleurostomatida) from the South China Sea,with Note on Phylogeny of A. dragescoi sp. n.

Two new and one problematic species of pleurostomatids, Amphileptus dragescoi sp. n., A. wilberti sp. n., and A. marinus from coastal areas of the South China Sea, are described based on observations of live and protargol‐impregnated specimens. Amphileptus dragescoi is different from its congeners by the presence of an apical group of extrusomes and the possession of 12–15 right and five left somatic kineties, two macronuclear nodules, and a single terminally positioned contractile vacuole. Amphileptus wilberti is diagnosed by oval or pyriform body, 15–19 right and seven or eight left somatic kineties, extrusomes arranged only in anterior portion of oral slit, usually three ventrally located contractile vacuoles, and two macronuclear nodules. Amphileptus marinus (Kahl, 1931) Song et al., 2004 is redescribed and its diagnosis is improved. One isolate which was misidentified as A. marinus by Song et al. (2004) is believed to represent an unknown form, named here as Amphileptus songi sp. n. Phylogenetic analyses of the SSU rDNA sequences indicate that the genus Amphileptus is paraphyletic, but its monophyly is not rejected by statistical tree topology tests.     

Redescription of Antetintinnidium mucicola (Claparède and Lachmann, 1858) nov. gen., nov. comb. (Alveolata,Ciliophora, Tintinnina)

Tintinnid ciliates have traditionally been described and classified exclusively based on their lorica features. Although information on the cell characters is urgently needed for a natural classification, more molecular than cytological data has been accumulated over recent years. Apparently, the tintinnids developed in the marine environment and entered freshwater several times independently. Typical freshwater tintinnids belong to the genera Tintinnidium and Membranicola. The species are comparatively well‐known regarding their morphology and characterised by two unusual de novo originating ciliary rows, the ventral organelles. In contrast, the cell features in the marine/brackish Tintinnidium species, specifically their somatic ciliary patterns, are insufficiently known or not known at all. Therefore, the morphology of a common marine/brackish representative, Tintinnidium mucicola, is redescribed based on live observation and protargol‐stained material. Furthermore, biogeographical and autecological data of the species are compiled from literature and own records. The phylogenetic relationships of T. mucicola are inferred and the diversity of the family Tintinnidiidae is assessed from 18S rDNA sequences. The study shows that T. mucicola is not only molecularly distinct, but also characterised by many plesiomorphic features, for instance, it does not possess a verifiable homologue to the ventral organelles. Hence, a new genus, Antetintinnidium nov. gen., is established for T. mucicola. The new insights into the diversity of Tintinnidiidae shed light on the early evolution of tintinnids and might provide clues on their adaptions to freshwater.     

Morphological description of three marine ciliates (Ciliophora, Scuticociliatia), with establishment of a new genus and two new species

Three marine scuticociliates, Falcicyclidium fangi nov. gen., nov. spec., Falcicyclidium atractodes nov. spec., and Cristigera media Kahl, 1928 were investigated using live observation and silver impregnation methods. The genus Falcicyclidium is distinguished by the combination of: (i) dorsoventrally flattened body, (ii) hook-like (falciform) paroral membrane, (iii) anterior end of paroral membrane posterior to anterior end of membranelle 1, and (iv) multiple caudal cilia. Falcicyclidium fangi nov. spec., the type of the new genus, can be recognized by the combination of its large size, extremely dorsoventrally flattened (3:1) body, consistently 10 somatic kineties, and the broad, elongate buccal area occupying 60% of the body length. Falcicyclidium atractodes nov. spec. is mainly characterized by a unique spine projecting from both the anterior and posterior end. The uncommon form, Cristigera media is redescribed based on the population from Qingdao, the statistic data and additional features, especially the morphology of the living cells, are documented.     

Morphology and Molecular Phylogeny of Two Poorly Known Species of Protocruzia (Ciliophora: Protocruziida)

The ciliate genus Protocruzia is a highly confused group, which was formerly placed in the class Heterotrichea or Karyorelictea, and is according to the most recent system tentatively assigned to the class Spirotrichea. In the present study, the morphology, ciliary pattern, and molecular phylogeny of two poorly known species, Protocruzia tuzeti Villeneuve‐Brachon, 1940, and Protocruzia granulosa Kahl, 1933, isolated from coastal waters of China, were investigated. Protocruzia tuzeti differs from its congeners mainly in possessing 6 adoral membranelles, 8–11 somatic kineties, and postoral dikinetids. Protocruzia granulosa is characterized by its extremely slender body, three postoral kineties, and 13 or 14 somatic kineties. The morphogenesis of P. granulosa is similar to that of P. tuzeti, especially in the parakinetal mode of stomatogenesis and the reorganization of the parental paroral membrane; however, more than one somatic kinety joins in the formation of the oral primordium in P. granulosa. Phylogenetic analyses based on small subunit ribosomal RNA gene revealed that six Protocruzia species form a fully supported clade that does not belong to any ciliate class; therefore, our data support the establishment of the class Protocruziea Gao et al. (Sci. Rep., 6, 2016, 24874).     

Phylogeny of the order Choreotrichida (Ciliophora, Spirotricha, Oligotrichea) as inferred from morphology, ultrastructure, ontogenesis, and SSrRNA gene sequences

The phylogeny within the order Choreotrichida is reconstructed using (i) morphologic, ontogenetic, and ultrastructural evidence for the cladistic approach and (ii) the small subunit ribosomal RNA (SSrRNA) gene sequences, including the new sequence of Rimostrombidium lacustris. The morphologic cladograms and the gene trees converge rather well for the Choreotrichida, demonstrating that hyaline and agglutinated loricae do not characterize distinct lineages, i.e., both lorica types can be associated with the most highly developed ciliary pattern. The position of Rimostrombidium lacustris within the family Strobilidiidae is corroborated by the genealogical analyses. The diagnosis of the genus Tintinnidium is improved, adding cytological features, and the genus is divided into two subgenera based on the structure of the somatic kineties. The diagnosis of the family Lohmanniellidae and the genus Lohmanniella are improved, and Rimostrombidium glacicolum Petz, Song and Wilbert, 1995 is affiliated.     

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.