Perioral Kinety Research Articles

Morphological and molecular examination of the ciliate family Lagynusidae (Protista, Ciliophora, Prostomatea) with descriptions of two new genera and two new species from China

Ciliates in the class Prostomatea play an important role in the global microbial loop due to their significant abundances and broad feeding strategies at the foundation of food webs. Despite their importance in ecosystems, the taxonomy and systematics of this group of ciliates has long been poorly understood, with this being especially true for members of the family Lagynusidae. Here we examine four lagynusids collected from sandy beaches in China, using silver-staining and 18S rRNA gene sequencing techniques. These investigations revealed two new genera and two new species and provided details for two little known forms: Penardella marina gen. nov., sp. nov., Apolagynus cucumis (as reported by Penard. Études sur les infusoires d’eau douce. Georg and Cie, Genève, 1922) gen. nov., comb. nov., Lagynus minutus sp. nov., and Lagynus elegans (Engelmann in Z Wiss Zool 11:347–393, 1862) Quennerstedt (Acta Univ Lund 4:1–48, 1867). Penardella gen. nov. can be morphologically distinguished by having more than three dikinetidal perioral kineties. Apolagynus gen. nov. differs from the closely related genus Lagynus in the absence of a conspicuous neck-like region. The ciliature of Apolagynus cucumis is revealed here for the first time, which demonstrates the classification of this species within Lagynusidae. Furthermore, Apolagynus binucleatus (Jiang et al., 2021) comb. nov. is established according to the new finding. The results of our phylogenetic analyses based on the 18S rRNA gene support the establishment of two new genera and indicate that Lagynusidae is monophyletic, which further strengthens its valid taxonomic status.

Reconstruction of Evolutionary History of Pleurostomatid Ciliates (Ciliophora, Litostomatea, Haptoria): Interplay of Morphology and Molecules

Pleurostomatids are raptorial ciliates that form a very distinct group within the Haptoria. Traditionally, the order Pleurostoma- tida was divided into two families: the Amphileptidae with two perioral kineties and a suture formed by the right side ciliary rows, and the Litonotidae with three perioral kineties and without suture. However, molecular phylogenies depicted the traditional Amphileptidae as a paraphyletic assemblage nesting also the Litonotidae. To overcome this problem we have analyzed genealogy of pleurostomatids using morphological data and 18S rRNA gene sequences, including newly sequenced genera Acineria and Kentrophyllum. Specifically, we have combined a morphological and molecular approach and have used also some other phylogenetic tools such as phylogenetic networks, split spectrum analysis, quartet mapping as well as the likelihood method of tracing history of morphological characters. These analyses show that: (1) there are not two but three distinct pleurostomatid lineages - Epiphyllidae fam. nov., Amphileptidae and Litonotidae; (2) epiphyllids (Epiphyllum + Kentrophyllum) represent a basal pleurostomatid group which is defined by two perioral kineties, by the presence of a suture on both the right and the left side of the body, by the loss of the oral bulge extrusomes, and by the extrusome fringe extending all around the body except for the oral region; (3) the families Amphileptidae and Litonotidae are monophyletic each, and represent sister groups; (4) Acineria belongs to the Litonotidae, as already indicated by morphological data; (5) Loxophyllum is a monophyletic and crown genus of the Litonotidae; and (6) Litonotus is paraphyletic, which could be very likely caused by a rapid radiation event that did not allow primary nucleotide homologies to be fixed.

Taxonomic studies on three marine ciliates from China, including a new species (Ciliophora, Cyrtophorida)

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.

A New Species of the Genus Metacystis (Ciliophora, Prostomatida, Metacystidae) from a Wastewater Treatment Plant

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 degrees C) were recorded.

Three marine haptorid ciliates from northern China: Paraspathidium apofuscum n. sp., Trachelotractus entzi (Kahl, 1927) Foissner, 1997 and Apotrachelotractus variabialis Long, Song and Warren, 2009 (Protozoa, Ciliophora)

Three haptorid ciliates, Paraspathidium apofuscum n. sp., Trachelotractus entzi (Kahl, 1927) Foissner, 1997 and Apotrachelotractus variabialis Long, Song and Warren, 2009, isolated from sandy beaches in Qingdao, China, were morphologically investigated using both in vivo observations and silver impregnation methods. The new species, P. apofuscum, is highly contractile and has a terminally-located contractile vacuole, approximately 40 somatic kineties, and a dikinetid perioral kinety that does not form a closed circle. Redescriptions of A. variabialis and T. entzi are also provided based on the Qingdao populations.

Ontogenesis of Dileptus terrenus and Pseudomonilicaryon brachyproboscis (Ciliophora, Haptoria)

Dileptids are haptorid ciliates with a conspicuous proboscis belonging to the oral apparatus and carrying a complex, unique ciliary pattern. We studied development of body shape, ciliary pattern, and nuclear apparatus during and after binary fission of Dileptus terrenus using protargol impregnation. Additional data were obtained from a related species, Pseudomonilicaryon brachyproboscis. Division is homothetogenic and occurs in freely motile condition. The macronucleus is homomeric and condenses to a globular mass in mid-dividers. The proboscis appears in late mid-dividers as a small convexity in the opisthe's dorsal brush area and maturates post-divisionally. The oral and dorsal brush structures develop by three rounds of basal body proliferation. The first round generates minute anarchic fields that will become circumoral kinetofragments, while the second round produces the perioral kinety on the right and the preoral kineties on the dorsal opisthe's side. The dorsal brush is formed later by a third round of basal body production. The formation of various Spathidium-like body shapes and ciliary patterns during ontogenesis and conjugation of Dileptus shows a close relationship between spathidiids and dileptids. On the other hand, the peculiarities of the dileptid morphology and ontogenesis indicate a long, independent evolution.

Establishment of a New Amphileptid Genus, Apoamphileptus nov. gen. (Ciliophora, Litostomatea, Pleurostomatida), with Description of a New Marine Species, Apoamphileptus robertsi nov. spec, from Qingdao, China

A new pleurostomatid genus Apoamphileptus is described, which is diagnosed as: Belonging to the Amphileptidae with spica on right side; on each side of the cell, a single perioral kinety, which encircles the cytostome and does not extend to the posterior end of the cell; somatic kineties of both sides near ventral margin shortened and forming a postoral suture; two to several extra fragments with densely arranged dikinetids located in anterior portion of left side. As the type species, the morphology and infraciliature of Apoamphileptus robertsi nov. spec., isolated from a shrimp-farming pond near Qingdao (Tsingtao), China, have been investigated using living observations and the protargol silver impregnation method. The diagnosis for this new species is: Apoamphileptus 90-180 x 30-60 microm in vivo, body elongate pyriform-shaped and slightly flattened; with one cross-striated band along the cytostome; 2-6 (generally 4) large macronuclear nodules, one micronucleus; 33-43 right somatic kineties; left side 6-8 kineties; two extra anterior fragments on left side; about 13 contractile vacuoles dispersed throughout whole body; extrusomes absent or not recognizable; marine habitat. Some morphologically related morphotypes are discussed and tabulated. Regarding the pattern of infraciliature and other morphological features, the well-described fresh-water species, Amphileptus claparedii Stein, 1867 is believed to be a member of this new genus, hence a new combination is suggested: Apoamphileptus claparedii (Stein, 1867) nov. comb.

Re-establishment of the cyrtophorid genus Coeloperix Deroux, nov. gen., with a description of Coeloperix sleighi nov. spec. (Protozoa, Ciliophora, Cyrtophorida)

The cyrtophorid genus Coeloperix, which has remained invalid for over 20 years, is re-established. This taxon is characterized by Lynchellids without podites on the ventral side; somatic kineties making no noticeable naked gap between left and right areas; pre- and post-oral kineties completely separated; two terminal fragments; perioral kineties consisting of one continuous anterior and two detached posterior rows; with cross-striated band around perimeter between ventral and dorsal surfaces. Based on this definition, two nominal species formerly placed in the invalid genus have been included again in Coeloperix: Coeloperix dirempta (Deroux, 1970) nov. comb. [synonym: Lynchella dirempta; Deroux, 1970], C. aspidisciformis (Kahl, 1933) nov. comb. [syn. Lynchella aspidisciformis; Kahl, 1933]. Another two morphotypes C. eforiana (Tucolesco, 1962) nov. comb. [syn. Lynchella eforiana; Tucolesco, 1962] and C. lynchelliformis (Borror, 1972) nov. comb. [syn. Chlamydodon lynchelliformis; Borro, 1972] have been transferred into the new genus. The morphology of living cells and infraciliature of a new species, C. sleighi nov. spec., isolated from the coastal area of China, have been investigated. It is diagnosed by: size about 40×30 μm in vivo; consistently 4 preoral and 15–16 postoral kineties; 12–16 nematodesmata; cross-striated band with two separations in the equatorial area; 3–4 (usually 3) finger-like tentacles on the ventral side; macronucleus ellipsoidal; two contractile vacuoles diagonally located; marine habitat.

Redescription and neotypification of Amphileptus marinus (Kahl, 1931) nov. comb. (Ciliophora, Pleurostomatida), and reactivation of A. parafusidens Song & Wilbert, 1989

Amphileptus marinus (Kahl, 1931) nov. comb. [basonym: Lionotus ( Hemiophrys) marina Kahl, 1931], a large marine benthic ciliate which has been “forgotten” for a long time was recently re-identified in samples isolated from the coastal water of the Yellow Sea, north China. The morphology of living cells and the infraciliature were investigated in the present work, which demonstrates that this is a valid and a “true” Amphileptus and hence a new combination is suggested. Based on the Chinese population and original description, a redefinition and redescription have been supplied. The diagnosis for this species is: large marine Amphileptus in vivo about 200–450 μm long with a slender lanceolate body, two macronuclear nodules, several micronuclei; two perioral kineties, 10–12 left and 20–27 right somatic kineties; several contractile vacuoles positioned near the ventral margin in the posterior half of the cell; extrusomes bar-shaped, c. 12 μm long in vivo, densely arranged along ventral edge. Some morphologically related taxa are compared and a neotype is designated. Because of the conspicuous differences in vivo between Amphileptus parafusidens Song & Wilbert, 1989 and Lionotus punctatus Kahl, 1926, the proposal by Foissner et al. (1995) that these two organisms might be conspecific is discussed and rebutted. Morphometric data demonstrate also that A. parafusidens should be clearly separated from the seemingly misidentified form, Amphileptus punctatus sensu Foissner, 1984. Identification of three morphotypes is discussed and compared.

Ciliates from Antarctic sea ice

Five ciliates, Chlamydonella prostomata nov. sp., Paractedoctema acruosa nov. gen., nov. sp., Urocyclon ovatum nov. gen., nov. sp., Porpostoma grassei (Corliss and Snyder 1986) and Cytharoides balechi Tuffrau 1974, collected from sea ice in the Weddell Sea, Antarctica were morphologically and taxonomically investigated. The new genus Paractedoctema is characterized as: Cyclidiidae with naked snout-like apical end and three well-developed membranelles which are multi-rowed in structure and closely apposed one to another; paroral membrane extending anteriorly to about mid-level of M1; one caudal cilium; and silverline system Cyclidium-like. Since Urocyclon Small and Lynn 1985 is a nomen nudum because no type species has been fixed, we re-establish the genus and give a revised definition: uronematids mostly with inverted pear-shaped body and subequatorially positioned cytostome; apical plate dominant; membranelle 1 highly reduced; and paroral membrane extending anteriorly to about mid-level of membrane 2. Based on this new definition, a new combination is suggested: Homalogastra cymruensis (Perez-Uz and Hope 1997) comb. nov. (formerly Urocyclon cymruensis Perez-Uz and Hope 1997). For the well-known genus Chlamydonella, an improved diagnosis has been given according to our observations and the data obtained: Lynchellidae without plasmatic protrusions on ventral side; several to many somatic kineties making no noticeable naked gap between left and right areas; perioral kineties continuous or slightly fragmented with leftmost rows parallel to each other, which are arched transversely; and cytopharyngeal rods (nematodesmata) toothed. Macronucleus usually dimorphic. Regarding the related genus Lynchella Kahl 1933, we suggest that the original diagnosis by Kahl should be maintained. Thus, the genus diagnosis is re-provided: Lynchellidae with plasmatic protrusions on ventral side; several to many somatic kineties making no noticeable naked gap between left and right areas; perioral kineties continuous or fragmented with some rows parallel to each other; cytopharyngeal rods toothed; macronucleus generally dimorphic. In the light of the redefinition, a new combination has been made: Chlamydonella nordica (Jankowski 1968) comb. nov. (formerly Lynchella nordica Jankowski 1968).

Morphology and Ecology of Siroloxophyllum utriculariae (Penard, 1922) N. G., N. Comb. (Ciliophora, Pleurostomatida) and an Improved Classification of Pleurostomatid Ciliates

ABSTRACT. The morphology and infraciliature of Siroloxophyllum utriculariae (Penard, 1922) n. g., n. comb. were studied in live cells, with the scanning and transmission electron microscope, as well as in specimens impregnated with protargol and silver carbonate. The new genus, Siroloxophyllum, belongs to the Loxophyllidae and has a specific combination of characters, viz. an oral bulge surrounding almost the entire cell, three perioral kineties, a single brush kinety, and a single right dorsolateral kinety. The ecology and faunistics of S. utriculariae are reviewed. It is a rare and infrequent predator preferring clean freshwaters. The somatic monokinetid of S. utriculariae has typical haptorid ultrastructure, including two transverse microtubular ribbons. The oral bulge is patterned string‐like with riffles containing the transverse microtubular ribbons originating from the oral kinetids. Perioral kineties 1 and 2 consist of dikinetids having one basal body each ciliated; the nonciliated basal body is associated with a nematodesmal and a transverse microtubular ribbon. Perioral kinety 3 consists of ciliated monokinetids having a fine structure similar to the somatic kinetids; they form triads with the dikinetids from perioral kinety 2. The classification of pleurostomatid ciliates is reviewed. Two suborders (Amphileptina, Litonotina) and three families (Amphileptidae, Litonotidae, Loxophyllidae n. fam.) are recognized and defined.

Beiträge zur ciliatenfauna (Protozoa: Ciliophora) der Amper (Bayern, Bundesrepublik Deutschland)

Summary Three new and 2 little known ciliates occurring in the small river Amper (Bavaria, F. R. G.) are described. The diagnoses base on live observations, protargol stained specimens, and on morphometrical techniques. Chlamydonellopsis nov. gen.: Lynchellidae with a single, sligthly curved perioral kinety above the cyrtos. Chlamydonellopsis plurivacuolata nov. spec. has 4 contractile vacuoles, whereas C. polonica ( Foissner, Czapik & Wiackowski , 1981) nov. comb, has only 2 vacuoles. Pseudochilodonopsis caudata ( Perty , 1852) nov. comb. is resurrected and is characterized by the pointed posterior end which is turned to the right. The diagnosis of the genus Alinostoma ( Jankowski , 1980) is improved: Oblong Chilodonellidae, the praoral kinety of which is irregularly fragmented. Many contractile vacuoles in 2 rows. Alinostoma burkli nov. spec. differs from A. plurivacuolata ( Deroux & Dragesco , 1986) by the shape of the dorsal body which does not project the ventral side. The somatic kineties of Tintinnidium semiciliatum ( Sterki , 1879), a remarkable non-pelagic “Aufwuchs” species, consist of monokinetids and dikinetids. This separates T. semiciliatum distinctly from other pelagic fresh-water tintinnids the somatic kineties of which consist either of monokinetids or dikinetids. Oxytricha haematoplasma nov. spec, is separated from other oxytrichids by a diffusely (non granular) reddish coloured cytoplasm, yellow subpellicular granules, 4 dorsal kineties, and a single caudal cirrus.

Morphologie und Infraciliatur von Perispira pyriformis nov. spec., Cranotheridium foliosus ( Foissner, 1983) nov. comb. und Dileptus anser ( O. F. Müller, 1786) (Protozoa, Ciliophora)

Summary The morphology and the infraciliature of Perispira pyriformis nov. spec., Cranotheridium foliosus ( Foissner , 1983) nov. comb., and Dileptus anser Muller , 1786 are described from small alpine water bodies. Perispira pyriformis differs from known species of this genus by its marked pear-shaped body. The infraciliature consists of approximately 19 somatic kineties, 1 perioral kinety with paired basal bodies and a dorsal brush of 3 rows. The spiraling oral bulge may be derived from the straight oral bulge of Spathidium . This is supported by the observation that nematodesmata occur only in the anterior part of the oral bulge. Cranotheridium foliosus differs from the other species of this genus by its body shape and the nuclear apparatus. The infraciliature consists of about 25 somatic kineties and 1 perioral kinety with paired basal bodies from which very delicate nematodesmata originate. The dorsal brush is composed of several short rows at the left lateral side and 3 longer rows at the dorsal side. Perispira pyriformis and Cranotheridium foliosus have the peculiarities of the Spathidiidae and can be classified without difficulty into this family. Dileptus cygnus Claparede and Lachmann , 1859 is synonym with Vibrio anser O. F. Muller , 1786 (compare Dingfelder 1962). It is characterized by the conspicuous long and contractile proboscis and numerous contractile vacuoles extending to the top of the proboscis. The strongly varible number of the somatic kineties in different populations (see Grain and Golinska 1969) suggests the occurrence of presently inseparable sibling species.

Morphology and Morphogenesis of Fuscheria terricola n. sp. and Spathidium muscorum (Ciliophora: Kinetofragminophora)1

ABSTRACTThe morphology and morphogenesis of the kinetofragminophoran soil ciliates, Fuscheria terricola n. sp. and Spathidium muscorum Dragesco & Dragesco‐Kerneis, 1979, are described. Stained specimens (protargol) are characterized biometrically. The new species differs from the other species of the genus in its body size, body shape, number of kineties, length of extrusomes, and habitat. Both species have telokinetal stomatogenesis, which commences with a proliferation of kinetosomes at those kineties which bear the brosse. Fuscheria terricola does not have a complex perioral ciliature; indeed, it might be that this species has only monokinetids. Thus only a proliferation of kinetosomes and the separation of the kineties takes place in the prospective division furrow. In contrast, S. muscorum differentiates short dikinetid kinetofragments in the region of the division furrow, which are arranged to form the perioral kinety of the opisthe in the intermediate and late stages of the stomatogenesis. The right part of the perioral kinety develops first. This and other studies show that telokinetal stomatogenesis proceeds very differently depending on the differentiation of the oral ciliature; however, detailed studies on the morphogenesis of kinetofragminophoran ciliates are still too few in number for subtypes to be defined.

Die Infraciliatur und das Silberliniensystem von Sagittaria hyalina nov. spec., Chlamydonella polonica nov. spec. und Spirozona caudataKahl, 1926 (Protozoa, Ciliophora)

The morphology and ecology of Sagittaria hyalina nov. spec, Chlamydonella polonica nov. spec, and Spirozona caudata Kahl , 1926 were investigated. Sagittaria hyalina occurred in an ephemeral puddle of a path. Its somatic and oral infraciliature is very similar to that known from Platyophrya . However, its silverline system is very similar to that known from Colpoda and Cyrtolophosis . This particular combination of features supports the maintenance of the family Sagittariidae (R. and L. Grandori , 1935) which is shifted from the Hymenostomata to the Colpodida. Chlamydonella polonica is a beta-mesosaprobic up to alpha-mesosaprobic ciliate that differs from other species of the genus mainly by the lack of a Y-shaped perioral kinety. Spirozona caudata occurred in the mud of an alpha-mesosaprobic stream. The somatic infraciliature consists of 21 strongly left spiraled ciliary meridians, 9 of them form a ribbon-like structure at the right side of the body. Its oral apparatus is tetrahymenal. Although the infraciliature has some features in common with that one of the genus Colpidium the family Spirozonidae Kahl , 1926 is maintained. This is supported by the particular somatic infraciliature and some special structures of the oral apparatus. However, the Spirozonidae must be shifted from the Trichostomata to the Tetrahymenina. Es wurden die Morphologie und die Ökologie von Sagittaria hyalina nov. spec, Chlamydonella polonica nov. spec, und Spirozona caudata Kahl , 1926 untersucht. Sagittaria hyalina wurde in einer ephemeren Wegpfütze gefunden. Die somatische und orale Infraciliatur ist sehr ähnlich jener von Platyophrya . Das Silberliniensystem gleicht dagegen jenem der Gattungen Colpoda und Cyrtolophosis . Diese eigenartige Merkmalskombination spricht für die Aufrechterhaltung der Familie Sagittariidae (R. und L. Grandori, 1935), die aus den Hymenostomata herausgenommen und zu den Colpodida gestellt wird. Chlamydonella polonica , ist ein beta- bis alphamesosaprober Ciliat, der sich von den anderen Arten der Gattung besonders durch das Fehlen einer Y-förmigen perioralen Kinete unte scheidet. Spirozona caudata wurde im Schlamm eines alphamesosaproben Vorfluters gefunden. Die somatische Infraciliatur besteht aus 21 stark links spiralig verlaufenden Somakineten, von denen 9 auf der rechten Seite des Tieres stark verdichtet sind. Der Oralapparat ist tetrahymenid. Obwohl die Infraciliatur auffallende Gemeinsamkeiten mit jener der Gattung Colpidium aufweist, wird die Familie Spirozonidae Kahl , 1926 aufrechterhalten. Dafür sprechen die besondere somatische Infraciliatur und einige spezielle Strukturen des Oralapparates. Sie muß aber aus den Trichostomata herausgenommen und zu den Tetrahymenina gestellt werden.