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The genus Apofrontonia comprises vicarious species that until now have only been described in a few locations worldwide. It was assigned to the family Frontoniidae based on two diagnostic features, i.e., the closely arranged kinetal rows in the peniculi and vestibular kineties on the right side of the vestibular cavity’s opening. The first phylogenetic analysis of the genus was based on the 18S rRNA gene, and it was limited not only by the unavailability of other gene sequences from other species within the genus but also by the Peniculia in general. Apofrontonia jejuensis n. sp. was discovered in the coastal waters of Jeju Island, South Korea. Besides the genus-specific features, A. jejuensis n. sp. exhibits a fibrillar system associated with the oral ciliature, likely linked to nematodesmata-like structures, as seen in Frontonia species. This study increases the taxon sampling, offers further insights in the morphological variability of the genus Apofrontonia, and provides additional molecular support for its distinction from the genus Frontonia.

This study provides the first report on a community of free-living ciliated protists from the chemoautotrophic cave ecosystem of Frasassi, Italy. This subterranean groundwater ecosystem represents a hotspot of biodiversity that still needs to be fully explored with particular reference to microbial eukaryotes such as protist ciliates. A total of 33 taxa of ciliates were identified along with one species each of flagellate, heliozoans and naked amoebae, from four main sampling sites, namely, Grotta Solfurea (GSO), Lago Verde (LVE), Ramo Solfureo (RSO), and Pozzo dei Cristalli (PDC). The last consists of small microhabitats/ponds presenting different chemical–physical and biological parameters, such as sulfur and nutrient contents and the presence of bacterial biofilms. Furthermore, an analysis of the cryptic ciliate species biosphere as a ‘seedbank’ of diversity against cave ecosystem disturbance was also performed. This study also highlights some peculiar adaptations of cave-dwelling ciliates not described in their noncave-dwelling conspecifics, such as the extreme photosensitivity of Urocentrum turbo, the cannibalism of Coleps hirtus, the variable number of thorns in Aspidisca species as a defensive response to predation, and the frequent reorganization of ciliary structures in Euplotes aediculatus. The 18S rDNA sequences were generated for five species and were compared with those of the noncave-dwelling conspecifics. Finally, our results shed light on the still largely unknown ciliate diversity in the chemosynthesis-based sulfidic groundwater ecosystem of Frasassi.

Dragon fruit or pitaya is an exotic tropical plant that brings multiple benefits to human health thanks to its high nutritional value and bioactive compounds, including powerful natural antioxidants. Extracts from stems, flowers, peels, pulps of dragon fruit own a range of beneficial biological activities against pathogenic microbes including bacteria, fungi and viruses, and diseases like diabetes, obesity, hyperlipidaemia, and cancer. Moreover, dragon fruit extracts have cardiovascular and hepatoprotective properties, as well as prebiotic potential. Vietnam is a tropical country with favourable climate conditions for the development of pitaya plantations, which have great adaptability and tolerance to a wide range of environmental conditions (e.g. salinity adaptation, favour light intensity, drought resistance, etc.). The dragon fruit, thanks to its nutritional properties, biological activities, and commercial value has become a cost-effective product for the Vietnamese economy, particularly in the poorest areas of the Mekong Delta region, and a driving force in the sustainable development of Vietnam under the challenges posed by the global climate change such as saline intrusion and drought.

Euplotes baugilensis n. sp. was discovered in a temporary puddle that formed after rainfall on a mountain footpath near Gangneung-Wonju National University in Gangneung, South Korea. After isolation, a pure culture was established, and the new species was examined using live observation, silver-impregnation (protargol and 'wet' silver nitrate), scanning electron microscopy, and the analysis of the 18S rRNA gene sequence. Morphologically, E. baugilensis n. sp. is characterized by small body size (on average 49 × 31 µm in vivo), 9 ordinary fronto-ventral cirri (cirrotype-9) with one reduced cirrus V/2 (composed of four non-ciliated basal bodies), 5 transverse cirri, 7 or 8 dorsolateral kineties, 6 dorsal prominent ridges, and a dargyrome (silverline system) of double type. In this study, we have used a combination of morphological and molecular techniques to characterize E. baugilensis n. sp. and determine its phylogenetic position within the genus Euplotes. Molecular analysis using 18S rRNA gene sequences indicated that E. baugilensis n. sp. is most closely related to E. curdsi (with a sequence identity of 96.8 %). [ABSTRACT FROM AUTHOR]

The morphology and morphogenesis of two stylonychid ciliates, Stylonychia ammermanni Gupta et al., 2001 and Tetmemena bifaria ( Stokes, 1887 ) Berger, 2001 , isolated from soil samples of Lombardia region, Northern Italy, and water samples from Cheonggancheon stream, South Korea, were investigated. The Italian population of S . ammermanni was found to be very similar in morphology to the Indian type population and the junior synonym S. harbinensis Shi and Ammermann, 2004 since most of the morphometric data overlapped. On the contrary, the Korean population of S. ammermanni showed some non-overlapping differences in ciliature suggesting a separation at subspecies level, i.e., S. ammermanni ammermanni and S. ammermanni koreana nov. subspec. Furthermore, the resting cyst of the Italian population of S. ammermanni has many ring-shaped structures on the surface which, however, were not observed in the Korean population. Phylogenetic analyses based on the SSU rRNA gene sequences show that the Italian and Korean populations of S. ammermanni fit well into the S. mytilus complex and moderately support the subspecies separation. Additionally, we split Tetmemena bifaria into two subspecies, viz., T. bifaria bifaria and T. bifaria minima nov. subspec. based on differences in the number of adoral membranelles and number of cirri in the marginal rows of the Italian and the Argentinian populations in comparison with the populations described by Wirnsberger et al. (1985) . [ABSTRACT FROM AUTHOR]

The genus Psilotricha was established by Stein in 1859, with P. acuminata as the type species within the family Oxytrichidae. This species lacked a full description until it was re-discovered in 2001, showing that its morphological and morphogenetic characters confirmed the inclusion in the family Oxytrichidae. Since then, the genus Psilotricha has had a convoluted taxonomy despite the morphological evidence available. In this paper, we describe a new Psilotricha species, Psilotricha silvicola n. sp., from woodland soils in Southern England (United Kingdom). The morphology was investigated in live and protargol-impregnated specimens. Our findings show that P. silvicola n. sp. shares morphological characteristics with P. acuminata, including the distinctive cell shape and the long and sparse cirri. Phylogenetic analysis of the 18S rRNA gene places this new species within the family Oxytrichidae, nested apart from the family Psilotrichidae (which includes the genera Urospinula , Psilotrichides and Hemiholosticha), in a clade containing species of the family Oxytrichidae. Furthermore, the morphology of another Psilotricha species, P. viridis , found in a freshwater pond in the same woodland area, is also here described, bringing additional insight into the taxonomy of the genus. Our findings provide further evidence for inclusion of the genus Psilotricha within the oxytrichids. [ABSTRACT FROM AUTHOR]

A new Euplotes species, isolated from abyssal depths (>4000 m) of the North Atlantic Ocean, was described based on morphology, ciliary pattern and molecular data. Euplotes dominicanus sp. n. is characterized by a small body size (29–40 × 17–27 μm in vivo), 18–22 adoral membranelles, 10 frontoventral, five transverse and two left marginal cirri and one caudal cirrus, five or six dorsolateral kineties with 7–9 dikinetids in mid-dorsolateral kinety (DK3), and dorsal silverline system of the double- eurystomus type. Phylogenetic analyses inferred from 18S rRNA sequences show that Euplotes dominicanus sp. n. is most closely related to E. curdsi, with a sequence similarity of 97.6 %. Euplotes dominicanus sp. n. was able to survive hydrostatic pressures up to 500 bar indicating its barotolerance. Metabarcoding data demonstrate the presence of E. dominicanus sp. n. in sediments of several deep-sea basins. [ABSTRACT FROM AUTHOR]

The morphology and morphogenesis of a new ciliate species, Neobakuella aenigmatica n. sp., which was discovered in an estuary in Korea, were investigated, using live observation, protargol impregnation, and scanning electron microscopy. This new species is characterized by a large (185-300 × 55-105 μm in vivo), elongate-ellipsoidal, flexible but not contractile body. It has ellipsoidal, yellowish cortical granules, 1.3 × 1.0 μm in size. The species has invariably 3 frontal and 2 frontoterminal cirri, about 5-10 buccal and 1-6 parabuccal cirri, 7 midventral rows, and 1 right and 2-4 left marginal rows. The outer left marginal row(s) consists of 1-7 short rows of cirri. The nuclear apparatus comprises 130 macronuclear nodules and 2 spherical micronuclei on average. The dorsal ciliature consists of 3 dorsal kineties. The leftmost left marginal row(s) likely develops from anlagen originating from both the rightmost and leftmost left marginal row(s). The molecular phylogenetic tree based on SSU rDNA suggests the nonmonophyly of the genus Neobakuella., (© 2019 International Society of Protistologists.)

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., (© 2017 The Authors Journal of Eukaryotic Microbiology published by Wiley Periodicals, Inc. on behalf of International Society of Protistologists.)

The identification of species within the genus Tetrahymena is known to be difficult due to their essentially identical morphology, the occurrence of cryptic and sibling species and the phenotypic plasticity associated with the polymorphic life cycle of some species. We have combined morphology and molecular biology to describe Tetrahymena aquasubterranea n. sp. from groundwater of Cape Town, Republic of South Africa. The phylogenetic analysis compares the cox1 gene sequence of T. aquasubterranea with the cox1 gene sequences of other Tetrahymena species and uses the interior-branch test to improve the resolution of the evolutionary relationships. This showed a considerable genetic divergence of T. aquasubterranea to its next relative, T. farlyi, of 9.2% (the average cox1 divergence among bona fide species of Tetrahymena is ~ 10%). Moreover, the analysis also suggested a sister relationship between T. aquasubterranea and a big clade comprising T. farleyi, T. tropicalis, T. furgasoni and T. mobilis. The morphological data available for these species show that they share with T. aquasubterranea a pyriformis-like life style and at least two of them, T. farleyi and T. mobilis, a similar type II silverline pattern consisting of primary and secondary meridians. Tetrahymena aquasubterranea exhibits a biphasic life cycle with trophonts and theronts, is amicronucleate, and feeds on bacteria., (© 2013 The Author(s) Journal of Eukaryotic Microbiology © 2013 International Society of Protistologists.)

Microdiaphanosoma arcuatum Wenzel, 1953 is a world-wide distributed ciliate, recorded mainly in soil samples, which we have also identified in ground water samples from South Africa. This ciliate has been frequently overlooked or not determined due to its small size, ∼12 μm. The genus Microdiaphanosoma is nowadays included in the class Colpodea, order Bryometopida, family Kreyellidae. The first complete small subunit (SSU) rDNA gene sequence of this ciliate was obtained from a South African isolate. Phylogenetic analysis including available SSU rDNA sequences from another Colpodea species in the GenBank strongly supported the position of M. arcuatum within the order Cyrtolophosidida instead of the order Bryometopida. The analysis also suggested a sister relationship between this species and species from the family Cyrtolophosididae., (© 2011 The Author(s). Journal of Eukaryotic Microbiology© 2011 International Society of Protistologists.)

Six soil samples from natural and cultivated sites of Saudi Arabia were investigated for ciliate diversity, using the non-flooded Petri dish culture method, live observation, and silver impregnation. We identified 135 species, all new for the fauna of Saudi Arabia, of which seven were undescribed: Spathidium alqasabi nov. spec.; Enchelyodon alqasabi nov. spec.; Metauroleptus arabicus nov. gen., nov. spec.; Pseudohemisincirra arabica nov. gen., nov. spec.; Saudithrix terricola​ Berger, Al-Rasheid and Foissner, 2006; Oxytricha arabica nov. spec.; and Erimophrya monostyla nov. spec. Based on Spathidium alqasabi, S. seppelti foissneri​ Vd'ačný et al., 2006 and S. seppelti etoschense​ Foissner et al., 2002 are raised to species rank; for the latter, a new name is required to avoid homonymy: Spathidium fraterculum nov. nom. The new genus Metauroleptus, which possesses two long and two to three short ventral cirral rows, generates all dorsal kineties intrakinetally and produces caudal cirri exclusively in dorsal kinety 1. Metauroleptus belongs to the hypotrichs, while family classification remains doubtful. The same applies to the new hypotrich genus Pseudohemisincirra, which has frontoventral and transverse cirri, while buccal cirri and caudal cirri are absent. The number of species contained in Saudi Arabian soils, including sand dunes, is in the range reported from other regions of the earth, suggesting that ciliates are well adapted to dry habitats, possibly mainly by their ability to produce very resistant resting cysts, most surviving for a long time due to reduced metazoan predation.