Morphology, Cell-Division, and Phylogeny of Schmidingerothrix Elongata Spec

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European Journal of Protistology 62 (2018) 24–42

Morphology, cell-division, and phylogeny of Schmidingerothrix elongata spec. nov. (Ciliophora, Hypotricha), and brief guide to hypotrichs with Gonostomum-like oral apparatus Xiaoteng Lua,b,c,1, Jie Huangd,1, Chen Shaoa,∗, Helmut Bergere,∗ aThe Key Laboratory of Biomedical Information Engineering, Ministry of Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China bUniversity of Innsbruck, Research Institute for Limnology, Mondseestrasse 9, 5310 Mondsee, Austria cInstitute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China dKey Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China eConsulting Engineering Ofﬁce for Ecology, Radetzkystrasse 10, 5020 Salzburg, Austria

Received 29 June 2017; received in revised form 2 November 2017; accepted 6 November 2017

Abstract

The hypotrich Schmidingerothrix elongata spec. nov., discovered in saline (20‰) soil of the Longfeng Wetland, Daqing, northern China, was studied using live observation and protargol impregnation. It is characterized, inter alia, by colorless cortical granules arranged in short rows, three frontoventral cirral rows with the rightmost extending far posteriorly, and 4–8, usually six macronuclear nodules. Cell division proceeds as in congeners and conﬁrms the lack of dorsal ciliature. In phylogenetic analyses based on SSU rDNA, S. elongata is sister of S. salinarum + Paracladotricha salina. A re-investigation of the type slides of P. salina, type of Paracladotricha, revealed a misobservation in the original description. Since P. salina lacks, like Schmidingerothrix spp., a dorsal ciliature, Paracladotricha becomes a junior, subjective synonym of Schmidingerothrix with S. salina comb. nov. as fourth species. A review of the phylogenetic analyses dealing with Schmidingerothrix shows that its position is variable. However, together with the gonostomatid oral apparatus it can be hypothesized that Schmidingerothrix is a member of the Gonostomatidae or a close relative. A list of genera (14) and species (58) which have – like Schmidingerothrix – a gonostomatid oral apparatus, as well as a key to these genera are provided. © 2017 Elsevier GmbH. All rights reserved.

Keywords: China; Guide; Longfeng Wetland; Saline habitat; Soil biology; Taxonomy

Introduction

Schmidingerothrix was established by Foissner (2012) for ∗Corresponding authors. S. extraordinaria Foissner, 2012, a peculiar hypotrichous cil- E-mail addresses: [email protected] (C. Shao), iate from highly saline soils in Africa. Somewhat later, two [email protected] (H. Berger). further species were described from saline waters in Europe 1 Co-first author. https://doi.org/10.1016/j.ejop.2017.11.001 0932-4739/© 2017 Elsevier GmbH. All rights reserved. X. Lu et al. / European Journal of Protistology 62 (2018) 24–42 25 and China, respectively, namely S. salinarum Foissner et al., China, on 6 May 2014. Samples were malodorous (very likely 20141 and Paracladotricha salina Shao et al., 2017, type due to hydrogen sulfide), and filled with rotten leaves and of Paracladotricha Shao et al., 20171. A re-analysis of the branches. For preservation and future isolation, samples were type material of P. salina showed that the dorsal ciliature dried at room temperature (about 24 ◦C) immediately after was incorrectly described resulting in synonymy of Para- collection. cladotricha and Schmidingerothrix. Ciliates were made to excyst by applying the non-flooded In January 2015, an obviously undescribed hypotrich was Petri dish method (Foissner et al., 2014). They were then isolated from saline soil of Longfeng Wetland, a district of isolated and non-clonal cultures were established at room Daqing, northern China. The analysis of its morphology and temperature (about 24 ◦C) in Petri dishes containing filtered cell division as well as the sequence of the small subunit soil percolate and squeezed rice grains to enrich the bacterial ribosomal DNA (SSU rDNA) indicate that it represents a food. further Schmidingerothrix species. Living specimens were observed using bright field and dif- The phylogenetic position of Schmidingerothrix in molec- ferential interference contrast microscopy (Foissner 2014). ular trees is uncertain for two reasons, namely (i) the type Protargol preparation was used to reveal the ciliature and the species was not sequenced (Foissner 2012), and (ii) the nuclear apparatus (Wilbert 1975). Counts and measurements other species can be found at various positions, for exam- of prepared specimens were performed at a magnification ple isolated as single branch (e.g., Foissner et al., 2014; Lu of 1000×. Drawings of protargol-prepared cells were made et al. 2015; present work), as sistergroup of the urostylids with the aid of a drawing device (camera lucida). To illustrate (Li et al. 2014; Luo et al. 2016, 2017), or in a cluster the changes occurring during morphogenesis, old (parental) with Gonostomum (Heber et al. 2014; Huang et al. 2016). structures are depicted by contour whereas new ones are Foissner (2012) put Schmidingerothrix into the monotypic shaded black. family Schmidingerotrichidae. In the discussion of division, Foissner et al. (2014, p. 73) compared Schmidingerothrix Terminology salinarum with “some supposed relatives, viz. Cladotricha, Gonostomum, and Wallackia”. The similarity with these gen- General terminology is mainly according to Lynn (2008); era is mainly due to the oral apparatus, which is more or less for terms specific for hypotrichs, see Berger (1999, 2006, gonostomatid in all these taxa. 2008, 2011) and Foissner and Al-Rasheid (2006). The tail- Berger (2011) assigned 33 species in seven genera to the length was measured according to the “1/3-method” (Chen Gonostomatidae Small & Lynn, 1985. However, since then et al. 2016). The frontoventral cirral rows are designated as several new species and genera have been described. Thus, ontogenetic numbering (Shao et al. 2014, 2017), that is, the we provide an updated list of genera and species with such an rows have the same designation as the anlagen from which oral apparatus. Together with an updated key to the genera, they originate. It should be noted that the Schmidingerothrix this will simplify the identification of species described after extraordinaria (type species of the genus) lacks cirral row I the revision of Gonostomum by Berger (2011). and II, thus frontoventral cirral row (FR) in Foissner (2012) is row III in the present paper; whereas the frontoventral cirral rows (V1–3) of S. salinarum (Foissner 2014) equal to row Material and Methods III–V in the present paper. Sample collection, isolation, and identification ZooBank registration Saline soil samples (0–10 cm; salinity of soil percolate ZooBank registration of present work (see Recom- about 20‰; pH 10.0) were collected in the Longfeng Wet- ◦ ◦ mendation 8A of ICZN 2012): urn:lsid:zoobank.org:pub: land (lat 46 35 30 N, long 125 13 08 E), Daqing, northern 410D9370-F872-4D66-8FED-460082AAEA5A.

1 The names Schmidingerothrix salinarum Foissner et al., 2014, Para- cladotricha Shao et al., 2014, and Paracladotricha salina Shao et al., 2014 DNA extraction, PCR amplification and have been mentioned in online-only (electronic-only) papers which lack a sequencing ZooBank registration in the work itself (Foissner et al. 2014; Shao et al. 2014). Due to this lack, these two works are not published in the sense of Genomic DNA was extracted from single cells using nomenclature and the new names mentioned therein are not available (ICZN, 2012, Article 8.5.3; further papers suffering on the same problem and cited DNeasy Tissue kit (Qiagen, CA) following the manufac- in the present work are those by Heber et al. 2014 and Bharti et al. 2015). turer’s instructions, with the modification that 25% of the In the present work, all names mentioned in such “unpublished” papers are volume suggested for each reagent solution was used. The disclaimed for nomenclatural purposes (ICZN, 1999, Article 8.3). The orig- SSU rDNA gene was amplified according to Gao et al. (2014), inal description of Paracladotricha and P. salina was recently published by using the primers 18S-F (5-AAC CTG GTT GAT CCT GCC Shao et al. (2017), the original description of S. salinarum is in preparation. AGT-3) and 18S-R (5-TGA TCC TTC TGC AGG TTC ACC However, as explained by Shao et al. (2017), such an “unpublished” paper remains available as a source of published descriptions and illustrations. TAC-3 )(Medlin et al. 1988). 26 X. Lu et al. / European Journal of Protistology 62 (2018) 24–42

Phylogenetic analyses ventral membranelles. Three, rarely four frontoventral cirral rows with three (row II), five (III), and 23 (IV) cirri on aver- The SSU rDNA sequence of Schmidingerothrix elongata age. Right and left marginal cirral row composed of about spec. nov. and those of 69 other hypotrichs were downloaded 27 and 22 cirri on average, respectively. 4–8, usually seven from GenBank database for the phylogenetic analyses (for (median) macronuclear nodules arranged in or slightly left of accession numbers, see Fig. 6). In preliminary tests, we used body midline, 1–4 micronuclei. euplotids as outgroup. Usually, the core urostylids were sister Type locality. Saline soil from the Longfeng Wetland, to the large clade containing Schmidingerothrix (or its junior Daqing, northern China (details, see Material and Methods). synonym Paracladotricha; see below) and most remaining Etymology. The species-group name elongat·us, -a, -um hypotrichs, which is in agreement with two previously pub- (Latin adjective [m; f; n]; elongated, stretched; Hentschel and lished trees (Foissner et al., 2014; Jung et al. 2015). Thus, for Wagner 1996) refers to body outline. Schmidingerothrix is the final analyses, five urostylids were selected as outgroup feminine (Foissner 2012) and thus S. elongata is the correct (Fig. 6). species name. Sequences were aligned in GUIDANCE and ambiguous Type material. The protargol slide (registration num- columns in the alignment were removed with set parame- ber LX201501050308) containing the holotype specimen ters (below 0.367), using the GUIDANCE web server (Penn (Fig. 1F, G; circled with ink on cover slide) has been deposited et al. 2010a,b). Further modifications were made manually, in the Laboratory of Protozoology, Ocean University of China using BioEdit 7.0 (Hall 1999). Ambiguously aligned regions (OUC). One paratype slide has been deposited in the Nat- and gaps were excluded prior to the phylogenetic analyses ural History Museum, London, UK (registration number: resulting in a matrix of 1,714 characters. Maximum likeli- NHMUK 2015.3.24.1). The remaining paratype slides were hood (ML) analysis was performed, using RAxML-HPC2 deposited at the same site as the holotype.

v8.1.1 on XSEDE (Stamatakis et al. 2008) on the online Description (Figs. 1A–G, 2A–L, Table 1). Body size

server CIPRES Science Gateway (Miller et al. 2010) with 100–150 × 15–30 ␮m in vivo (n = 12), usually 120 × 15 ␮m; theGTR+G+I model as the optimal choice. Support for in protargol preparations 120 × 29 ␮m on average, that is, the best ML tree came from 1000 bootstrap replicates with specimens distinctly widened due to the preparation pro- the GTR + CAT model. Bayesian inference (BI) analysis cedures (Table 1); length:width ratio about 6.5–11.0:1, on was performed with MrBayes v3.2.2 on XSEDE (Ronquist average 8.3:1 in vivo, whereas 4.1:1 on average in protargol and Huelsenbeck 2003) on the online server CIPRES Sci- preparations. Body in vivo usually slender, almost worm- ence Gateway, using the GTR+I+G model as selected by shaped, anterior end rounded or transversely truncate and MrModeltest v.2.0 (Nylander 2004). Markov chain Monte with more or less distinct protrusion in gap between frontal Carlo (MCMC) simulations were run with two sets of four and ventral adoral membranelles; rear body portion tail-like chains for 2,000,000 generations with a sampling frequency narrowed, occupies 5% (Fig. 2B) to 15% (Fig. 2D) of body of 100 and a burn-in of 5000 trees (25%). All remaining trees length, tail usually also well-recognizable in protargol prepa- were used to calculate posterior probabilities using a 50% rations (Fig. 1F, G); body indistinctly contractile, but rather majority rule consensus. TreeView v1.6.6 (Page 1996) and ﬂexible and thus cell outline variable, i.e., slightly sigmoidal, MEGA 4.0 (Tamura et al. 2007) were used to visualize the elongated, or more or less coiled (Figs. 1A, B, D, 2A–G). tree topologies. Body dorsoventrally ﬂattened about 2:1, ventral side slightly For interpretation of bootstrap values we follow Vd’acnˇ y´ convex, dorsal side slightly concave. Nuclear apparatus in or

and Rajter (2015), that is, we consider values ≥95 as high, slightly left of cell midline, composed of 4–8, on average of from 70–94 as moderate, from 50–70 as low, and <50 as no 6.5 macronuclear nodules and 1–4, on average two micronu- support (Hillis and Bull 1993). Bayesian posterior probability clei attached or near to macronuclear nodules (Fig. 1A, B,

values <0.95 are considered as low and values ≥0.95 as high D, G); macronuclear nodules slenderly ellipsoid to ellip-

(Alfaro et al. 2003). soid (length:width ratio about 1.2–2.0:1), micronuclei about

3 ␮m in diameter. Cortical granules colorless, about 0.5 ␮m in diameter, arranged in longitudinally oriented, short rows usually composed of 4–6 granules, rarely visible in protargol Results preparations (Figs. 1C, 2H). Cytoplasm colorless to grayish,

contains numerous shiny spherical inclusions (about 1–8 ␮m Schmidingerothrix elongata spec. nov. in diameter), making cell opaque and dark at low magniﬁca-

tion (Figs. 1A, B, 2A–G). Contractile vacuole not observed.

Diagnosis. Body in vivo 100–150 × 15–30 ␮m, highly Locomotion by rotation around longitudinal axis of cell, or ﬂexible, elongate (length:width ratio 8.3:1 on average in slow to moderately fast crawling on substrate; in cultures, life), with distinct, pointed tail occupying about 5–15% of cells usually aggregate around rice grains.

body length. Cortical granules about 0.5 ␮m across, color- Adoral zone terminates at about 25% of body length in vivo less, arranged in short rows. Adoral zone extends to about and at about 29% on average in protargol preparations, invari- 25% of body length, composed of three frontal and about 20 ably composed of three frontal and an average of 20 ventral X. Lu et al. / European Journal of Protistology 62 (2018) 24–42 27

Table 1. Morphometric characterization of Schmidingerothrix elongata spec. nov. (elo; original data) and comparison with congeners, namely S. extraordinaria (ext; from Foissner 2012), S. salinarum (sal; from Foissner et al., 2014; species not validly published, see footnote at introduction), and S. salina comb. nov. (saa; from Shao et al. 2014).

Charactera Species HT Min Max Mean M SD CV n

Body, length elo 130 95 130 119.6 120.0 10.6 8.8 25 ext – 52 86 70.1 70.0 7.8 11.2 21 sal – 68 93 81.6 83.0 7.7 9.4 21 saa 83 72 106 92.2 – 8.9 9.7 16 Body, width elo 26 20 40 29.0 29.0 6.1 21.0 25 ext – 12 23 17.3 18.0 3.5 20.3 21 sal – 14 24 18.0 18.0 2.9 15.9 21 saa 32 29 48 37.1 – 4.8 12.7 16 Body, length:width ratio elo 6.2 2.9 6.2 4.3 4.3 0.9 22.1 25 ext – 3.7 7.1 4.9 4.1 0.9 18.1 21 sal – 2.9 5.5 4.0 4.8 0.6 15.7 21 saa 2.5 1.5 3.3 2.4 2.3 0.5 20.7 15 Adoral zone of membranelles, elo 35 27 45 34.3 35.0 3.6 10.6 25 length ext – 18 25 20.6 21.0 1.8 8.6 21 sal – 22 33 26.5 26.0 2.5 9.3 21 saa 28 24 34 28.8 29.0 3.2 11.1 15 Frontal membranelles, number elo 3 3 3 3.0 3.0 0.0 0.0 25 ext – 3 3 3.0 3.0 0.0 0.0 21 sal – 3 3 3.0 3.0 0.0 0.0 21 saa b 3 3 3 3.0 3.0 0.0 0.0 16 Ventral membranelles, number elo 20 13 23 19.8 20.0 2.0 10.0 25 ext – 14 17 15.3 16.0 1.0 6.3 21 sal – 18 22 20.8 21.0 1.1 5.4 19 saa 19 – – – 21.0 – – 20 Endoral membrane, length elo 10 10 15 13.9 14.0 1.3 9.6 25 ext – 7 10 8.7 9.0 1.2 13.3 21 sal – 8 15 12.0 12.0 1.9 15.7 21 saa 12 8 14 11.3 12.0 1.7 14.8 15 Anterior body end to begin of elo 19 17 22 18.8 19.0 1.3 6.9 25 endoral membrane, distance ext – 8 14 10.4 10.0 1.5 14.1 21 sal – 10 15 12.7 13.0 1.4 10.9 21 saa 17 10 20 14.2 14.0 2.9 20.6 15 Frontal cirri, number eloc 0 0 0 0 0.0 0.0 0.0 25 ext – 1.0 2.0 1.2 1.0 – – 21 sal – 3.0 3.0 3.0 3.0 0.0 0.0 21 saa 3 3 3 3.0 3.0 0.0 0.0 16 Frontoventral cirral rows, elo 3 3 4 3.0 3.0 0.2 6.6 25 number ext – 1 1 1.0 1.0 0.0 0.0 21 sal – 3 3 3.0 3.0 0.0 0.0 29 saa 3 3 3 3.0 3.0 0.0 0.0 16 Frontoventral cirral row II, elo 3 3 4 3.1 3.0 0.3 9.0 25 number of cirri ext – 0 0 0.0 0.0 0.0 0.0 21 sal – 0 0 0.0 0.0 0.0 0.0 21 saa – 0 0 0.0 0.0 0.0 0.0 16 28 X. Lu et al. / European Journal of Protistology 62 (2018) 24–42

Table 1 (Continued)

Charactera Species HT Min Max Mean M SD CV n

Frontoventral cirral row III, elo 5 4 6 5.0 5.0 0.5 9.2 25 number of cirri ext – 2 6 3.4 3.0 0.9 25.4 21 sal – 2 5 4.1 4.0 0.7 18.3 21 saa 5 4 7 5.7 – 1.1 19.3 16 Frontoventral cirrial row IV, elo 24 19 30 23.2 23.0 2.9 12.7 25 number of cirri ext – 0 0 0.0 0.0 0.0 0.0 21 sal – 12 20 17.5 18 0.5 12.0 21 saa 15 12 25 17.7 – 3.8 21.5 16 Frontoventral cirral row V, elo – 18 27 22.5 22.5 – – 2 number of cirri ext – 0 0 0.0 0.0 0.0 0.0 21 sal – 2 12 5.3 5.0 2.5 47.9 21 saa 18 10 18 14.1 – 3.8 27.0 16 Anterior body end to posterior elo 10 8 12 10.2 10.0 0.7 7.3 25 end of frontoventral cirral row II, distance ext – 0 0 0.0 0.0 0.0 0.0 21 sal – 0 0 0.0 0.0 0.0 0.0 21 saa – 0 0 0.0 0.0 0.0 0.0 16 Anterior body end to posterior elo 17 13 19 16.3 17.0 1.4 8.5 25 end of frontoventral cirral row III, distance ext – 8 16 11.4 11.0 2.0 17.9 21 sal – 10 18 13.2 13.0 1.6 12.4 21 saa 36 36 78 58.2 62.0 11.1 19.0 15 Anterior body end to posterior elo 110 83 128 107.8 110.0 14.0 13.0 25 end of frontoventral cirral row IV, distance ext–––– – ––– sal – 50 73 61.4 60.0 6.6 10.7 21 saa 49 49 78 62.0 60.0 9.7 15.6 15 Anterior body end to posterior elo – 101 121 111.0 111.0 – – 2 end of frontoventral cirral row V, distance ext–––– – ––– sal – 7 73 26.2 19.0 – – 21 saa 48 50 76 63.0 61.0 9.2 16.2 15 Right marginal cirri, number elo 26 22 33 26.5 26.0 3.1 11.6 25 ext – 22 35 26.7 26.0 2.7 10.0 21 sal – 21 31 23.4 23.0 2.6 11.1 21 saa 25 20 31 25.8 – 3.4 13.2 16 Left marginal cirri, number elo 8 17 30 21.8 20.0 3.9 17.8 25 ext – 16 28 20.5 21.0 3.1 15.2 21 sal – 14 23 17.5 17.0 2.0 11.2 21 saa 4 13 25 18.3 – 3.3 18.0 16 Macronuclear nodules, number elo 2 4 8 6.5 7.0 1.5 23.6 25 ext – 4 5 4.0 4.0 0.3 7.9 21 sal – 3 6 4.2 4.0 0.6 14.7 29 saa 2 3 4 3.9 – 0.3 7.7 16 X. Lu et al. / European Journal of Protistology 62 (2018) 24–42 29

Table 1 (Continued)

Charactera Species HT Min Max Mean M SD CV n

Micronuclei, number elo 2 1 4 2.2 2.0 0.7 31.3 25 ext – 1 3 1.8 2.0 0.6 33.3 21 sal – 1 2 1.4 2.0 – – 29 saa 2 1 2 1.5 2.0 0.5 33.7 15 First macronuclear nodule, elo 9 5 30 10.4 9.0 5.6 53.9 25 length ext – 5 9 6.9 7.0 1.0 14.8 21 sal – 5 18 10.5 10.0 2.4 23.1 29 saa 16 9 16 11.6 11.0 1.8 15.8 15 First macronuclear nodule, width elo 4 3 11 5.6 5.0 1.8 31.7 25 ext – 3 5 3.4 3.0 0.6 16.8 21 sal – 3 6 4.0 4.0 0.6 16.0 29 saa 12 6 12.5 9.1 9.5 2.1 23.4 15 Micronuclei, length elo 3.0 2.5 5 3.1 3.0 0.5 14.8 25 ext – 2 5 3.0 3.0 1.0 32.0 21 sal – 2.5 4.0 3.2 3.0 0.4 12.1 29 saa 2.5 2 4 2.9 3.0 0.7 24.6 15 Micronuclei, width elo 3 1.5 4.5 3.0 3.0 0.5 15.8 25 ext – 1.2 2 1.8 1.8 0.3 15.4 21 sal – 1.5 3 2.1 2.0 0.3 15.1 29 saa 2.5 1.5 3.5 2.5 2.0 0.6 25.9 15 bData based on description. cMore or less distinctly off-set frontal cirri are lacking. a All data are based on protargol-preparations. Measurements in ␮m. Abbreviations: CV, coefﬁcient of variation in %; HT, holotype specimen (also included in sample n); M, median; Max, maximum; Mean, arithmetic mean; Min, minimum; n, number of cells measured; SD, standard deviation. -, data not available.

membranelles separated by a distinct gap; distal end of zone cirrus and cirri of other rows consisting of 2 × 2 basal bodies not extending posteriorly, DE-value thus 0.0 (Figs. 1A, B, (Fig. 1E). Frontoventral cirral row II usually composed of E, F, 2C, I, J, Table 1). Base of right frontal membranelle three cirri, including middle frontal cirrus, terminates dis-

smaller (2 × 2 basal bodies) than those of middle and left tinctly anterior of endoral membrane. Frontoventral cirral

frontal membranelle (each 2 × 4 basal bodies; Fig. 1E); cilia row III composed of ﬁve cirri on average including right

of frontal membranelles about 18 ␮m long in vivo; ventral frontal cirrus, terminates at or slightly ahead of level of ante- membranelles composed of only two long and one very short rior end of endoral membrane. Frontoventral cirral row IV

row of basal bodies (Fig. 1E), cilia decrease in length from composed of 23 cirri on average, commences slightly poste- about 18 ␮m anteriorly to 5 ␮m posteriorly in right half of rior to anterior body end (about 6% of body length in holotype

zone (Fig. 1A, B). Endoral membrane on average 14 ␮m long, specimen) and extends, like ventral cirral row V (if present composed of monokinetids, commences at 13–20%, on aver- at all) and marginal cirral rows, slightly helically on ventro- age at 16% of body length, terminates at posterior end of lateral side; row IV terminates at about 80% of body length adoral zone (Figs. 1E, F, 2K, Table 1). Paroral membrane in holotype (Fig. 1F). Frontoventral cirral row V composed absent, however, two of 25 specimens investigated have a of about 18 and 27 cirri, respectively; commencing at about second row of monokinetids(?) commencing right of ante- level of rear end of frontoventral cirral row III, terminating at rior end of endoral membrane and terminating at about half ca. 88% of body length (Fig. 1E). Right marginal cirral row length of endoral membrane (Fig. 2L). Presence/absence of begins dorsolaterally at anterior end of cell, terminates near lip fringes not checked. tip of tail. Left marginal cirral row begins near posterior end Cirral pattern rather simple because usually composed of of adoral zone, extends dorsally, and ends more or less subter- three frontoventral cirral rows (II–IV; two out of 25 speci- minally. Notably, the ﬁbres of the three frontal membranelles mens composed of four rows); one right and one left marginal intersect between the anteriormost cirri of frontoventral cirral row. Buccal cirrus, pretransverse ventral cirri, and transverse rows II and III, forming an inconspicuous dark spot, eas-

cirri lacking (Fig. 1E–G). Cirri 7–10 ␮m long in vivo. Dis- ily misinterpreted as frontal cirrus in heavily impregnated tinct frontal cirri lacking. Anterior two cirri of frontoventral specimens (Fig. 2I, J).

cirral row II composed of 2 × 3 basal bodies each, posterior 30 X. Lu et al. / European Journal of Protistology 62 (2018) 24–42

Fig. 1. Morphology and ciliature of Schmidingerothrix elongata spec. nov. (A–D, from life; E–G, protargol preparation). A, B. Ventral view of two representative individuals. C. Cortical granulation on ventral side. D. Various specimens showing ﬂexibility and variability of body shape and macronuclear apparatus. E. Ventral view of anterior body portion of a specimen with ﬁve frontoventral cirral rows; arrow indicates miniaturized right frontal membranelles. Note that the adoral membranelles are composed of three rows of basal bodies only. F, G. Ventral (F) and dorsal (G) view of holotype specimen, showing ciliature and nuclear apparatus; note that dorsal kineties and caudal cirri are lacking.

E, endoral membrane; FM, frontal adoral membranelles; LMR, left marginal row; Ma, macronuclear nodule; Mi, micronuclei; RMR, right

marginal row; VM, ventral membranelles; II–V, frontoventral cirral rows. Scale bars = 30 ␮m (A, B); 2.5 ␮m (C); 45 ␮m (D); 20 ␮m (E),

32 ␮m (F, G).

Dorsal ciliature genus-speciﬁc, that is, kineties and caudal nisable in the parental oral apparatus which is retained by the cirri are lacking (Fig. 1G). proter (Figs. 2V, 3A, C, E, G, 4A, C, E, G). Cell division of Schmidingerothrix elongata spec. nov. Frontoventral ciliature: In the opisthe, the frontoventral (Figs. 2M–W, 3A–H, 4A–H). This part of the life cycle is cirral anlagen II and III develop de novo to the right of the relatively straightforward due to the reduced ciliature. anterior portion of the oral primordium and the anlage of Oral apparatus: The oral primordium of the opisthe devel- the endoral (= frontoventral cirral anlage I). By contrast, the ops in mid-body near the left marginal cirral row (Figs. 2M, anlage for cirral row IV originates within the parental fron- 3A). The primordium divides forming a narrow right por- toventral cirral row IV (Figs. 2N–T, 3E, G, 4A, C, E). In the tion that becomes the anlage for the endoral membrane and a proter, the frontoventral cirral anlagen II, III, and IV develop wide left portion for the adoral zone of membranelles (Figs. within the parental rows (Figs. 2U, V, 3E, G, 4A, C, E). 2N–R, 3C, E, G). Subsequently, a short third row of basal bod- These anlagen elongate almost simultaneously by basal body ies is added to the ventral adoral membranelles; the endoral proliferation. No parental cirri are retained after division. anlage is likely composed of monokinetids (Figs. 2S, T, 4A). In specimens with four frontoventral cirral rows, row V is When the division furrow becomes visible, the left and middle obviously formed like row IV, namely, via the formation of frontal membranelles elongate slightly, while the right mem- anlagen within the parental row (Figs. 2W, 4E). branelle becomes smaller by resorbing basal bodies from left Marginal rows: Their formation proceeds as in most other to right side (Fig. 4C, E, G). No obvious changes are recog- hypotrichs, that is, two primordia originate within each row. X. Lu et al. / European Journal of Protistology 62 (2018) 24–42 31

Fig. 2. Photomicrographs of Schmidingerothrix elongata spec. nov. (A–H, from life; I–W, protargol preparation). A–G. Freely motile speci-

mens, showing variability of different body shapes. H. Distribution of cortical granules (about 0.5 ␮m in diameter) on ventral side. I, J. Ventral view of anterior body portion of two specimens showing, inter alia, the frontoventral ciliature, and the gap separating frontal and ventral adoral membranelles. Arrowheads indicate a dark spot where ﬁbres of frontal membranelles intersect; arrow in (J) marks rear end of frontoventral cirral row III. K, L. Endoral membrane; arrowhead in (L) denotes monokinetids right of endoral membrane. M–T, W. Development of oral primordium and frontoventral cirral anlagen in the opisthe; the specimen shown in (W) forms four frontoventral cirral rows (II–V). Double- arrowhead in (T) depicts the anlage for the right marginal row; arrows in (O–S) indicate anlage for the endoral membrane (= frontoventral

cirral anlage I). U, V. Development of frontoventral cirral anlagen in proter. II–V, frontoventral cirral anlagen II–V. Scale bars = 30 ␮m (A–G);

␮

10 m (I, J, U, V); 7 ␮m (K, L).

They become longer very likely due to formation of new Dorsal ciliature: During cell division no primordia, not basal bodies, but also by transformation of some parental even vestiges, could be recognized on the dorsal side (Figs. cirri (Figs. 2T, 3G, 4A–H). No parental cirri are retained for 3B, D, F, H, 4B, D, F–H). This conﬁrms the absence of dor- the next generation. 32 X. Lu et al. / European Journal of Protistology 62 (2018) 24–42

Fig. 3. Cell division in Schmidingerothrix elongata spec. nov. (protargol preparation). Ventral (A, C, E, G) and dorsal (B, D, F, H) views of two early (upper row) and two middle (lower row) dividers, showing development of oral primordium, formation of frontoventral and marginal cirral anlagen, and nuclear apparatus. Arrowheads in (E, G) mark anlage for endoral membrane (= frontoventral cirral anlage I). Arrows in (B) mark reorganisation band. Ma, macronuclear nodules; Mi, micronuclei; OP, oral primordium; RMA, anlage for the right marginal row;

RMR, right marginal row; II–IV, frontoventral cirral anlagen II–IV. Scale bars = 30 ␮m. sal kineties and caudal cirri in interphase specimens, ﬁrst The topologies of the ML and BI trees are similar and there- described by Foissner (2012). fore we only present the ML tree (Fig. 6). Schmidingerothrix Nuclear apparatus: Division proceeds as in gonostomatids elongata clusters with full support (ML/BI, 100/1.00) and most other hypotrichs (Figs. 2N–W, 3B, D, F, H, 4B, D, with S. salinarum + S. salina (for transfer of latter species F, H; Berger 1999, 2011). to Schmidingerothrix see below; for the type species S. Phylogenetic analyses based on SSU rDNA gene extraordinaria no gene sequence data are available). This sequences (Fig. 6). The SSU rDNA sequence of Schmidingerothrix cluster is sister to all other hypotrichs, Schmidingerothrix elongata spec. nov. was deposited in Gen- except for the urostylids which were ﬁxed as outgroup (see Bank database with the accession number KY085934. The Section “Material and methods”). length and GC content of the SSU rDNA sequence are Schmidingerothrix elongata differs from S. salinarum 1762 bp and 44.10%, respectively. in 36 bp and from S. salina also in 36 bp. By contrast, X. Lu et al. / European Journal of Protistology 62 (2018) 24–42 33

Fig. 4. Cell division in Schmidingerothrix elongata spec. nov. (protargol preparation). Ventral (A, C, E, G) and dorsal (B, D, F, H) views of a middle (A, B), three late (C–H) divider. Arrows in (A) mark right marginal row anlagen of proter and opisthe. Arrowheads in (E, G) denote formation of gap in adoral zone of opisthe. Division of nuclear apparatus proceeds as in most other hypotrichs. Note that the specimen shown in (E, F) forms an additional (V) frontoventral cirral row. E, parental endoral membrane; LMA, anlage for the left marginal row; Ma,

macronuclear nodules; Mi, micronuclei; RMA, anlage for the right marginal row; II–V, frontoventral cirral anlagen II–V. Scale bars = 30 ␮m. Schmidingerothrix salina differs from S. salinarum only in 2012. The type species, S. extraordinaria, was discovered 7 bp. in hypersaline soil of the Etosha National Park in Namibia. Slightly later, Foissner et al. (2014) found a second new species, S. salinarum, in a solar saltern in the Ria Formosa Discussion National Park near Faro, a town in Portugal. Almost simultaneously, Shao et al. (2014) described Paracladotricha salina, Generic assignment and comparison with now Schmidingerothrix salina (see next chapter), from a congeners (Fig. 5A–I) hypersaline, abandoned offshore mollusc-farming pond in the Jiaozhou Bay of Qingdao, China (for nomenclatural The absence of dorsal kineties and caudal cirri as well problems with S. salinarum, Paracladotricha and P. salina, as of a paroral membrane and of a buccal cirrus assign the see Introduction). For detailed, morphological comparison new species unequivocally to Schmidingerothrix Foissner, 34 X. Lu et al. / European Journal of Protistology 62 (2018) 24–42

Table 2. Morphological comparison of three features in the four Schmidingerothrix species, namely, S. extraordinaria (ext; from Foissner 2012), S. salinarum (sal; from Foissner et al., 2014; species not validly published, see footnote at introduction), S. salina (saa; from Shao et al. 2014, 2017), and S. elongata spec. nov. (elo; original data).

Character Species Average/character state

Frontal cirri distinctly off-set, number ext 1 sal 2 saa 2 elo 0 Frontoventral cirral rows, number ext 1 sal 3 saa 3 elo 3 Cortical granules ext Present sal Present saa Absent elo Present of the four species now assigned to Schmidingerothrix, see above: Schmidingerothrix salina (Shao et al. 2017) comb. Tables 1 and 2. nov. The classification of the new species in Schmidingerothrix Foissner (2012) established the monotypic family is not only supported by conspicuous morphological agree- Schmidingerotrichidae. In Shao et al. (2014, 2017), ments, but also by gene sequence data because S. elongata schmidingerotrichids comprise Schmidingerothrix and Par- is sister of a cluster composed of S. salinarum + S. salina acladotricha. Due to the synonymy proposed above, with maximum support (Fig. 6). On the other hand, the dis- Schmidingerotrichidae become again monotypic. tinct difference in the number of base pairs between the new species and S. salina (36 bp; corresponding 98% sequence similary) and S. salinarum (36 bp) supports the morphology- Morphogenesis based classification as new species (Nebel et al. 2011). Cell division of S. elongata proceeds basically as in the congeners and is rather simple due to the distinctly reduced ciliature (Foissner 2012; Foissner et al., 2014; Shao et al. Paracladotricha, a junior synonym of 2014). The main morphogenetic details can be summarized Schmidingerothrix as follows (Table 3, Fig. 5): (i) the parental adoral zone remains more or less unchanged and forms the adoral zone Shao et al. (2017) described a new species for which they of the proter; (ii) the parental frontoventral cirral rows are established the genus Paracladotricha (for explanation of involved in anlagen formation of the proter; (iii) in the opis- tricky nomenclature of this and other taxa described in an the, the oral apparatus and the short frontoventral cirral rows electronic-only journal, see footnote in the Introduction). (confined to the frontal area in interphasic specimens; e.g. According to the original description of P. salina, dorsal frontoventral cirral rows II and III in S. elongata) originate kineties are present, but highly reduced, that is, composed of de novo; (iv) long frontoventral cirral rows extending into only one or two basal body pairs in each row (Shao et al. 2014, the posterior half of the cell (e.g. frontoventral cirral row 2017). Due to the close relationship of Schmidingerothrix IV in S. elongata and S. salinarum are formed via anlagen elongata with S. salinarum and P. salina in the molecular originating within the parental rows); (v) rudiments of struc- tree (Fig. 6), we suspected that Shao et al. (2014) could have tures lacking in interphasic specimens (buccal cirrus, paroral misinterpreted the preparations. Thus, we re-examined the membrane, dorsal kineties, caudal cirri) are not recognisable protargol slides of P. salina and ascertained that, as in the during cell division; (vi) parental cirri are not retained for the other Schmidingerothrix species, dorsal kineties are absent. next generation. We found some small, stained particles that were obviously misinterpreted as basal body pairs. Since dorsal kineties are lacking, Shao et al. (2014) could not clarify the “forma- Notes on phylogeny of Schmidingerothrix tion” of the strongly reduced kineties. Thus Paracladotricha salina Shao et al., 2017 is type of the monotypic genus Para- The Schmidingerothrix species described so far have been cladotricha Shao et al., 2017 that becomes a subjective, junior analyzed molecular biologically, except for the type species synonym of Schmidingerothrix Foissner, 2012 as explained S. extraordinaria. Since a genus is primarily defined via the X. Lu et al. / European Journal of Protistology 62 (2018) 24–42 35

Fig. 5. Ciliature of Schmidingerothrix elongata (A, F), S. salina (B, G), S. salinarum (C, D, H), and S. extraordinaria (E, I) (A, F, original; B, from Shao et al. 2014; C, D, from Foissner et al., 2014; E, from Foissner 2012; G–I, originals after data from Shao et al. 2014, Foissner et al., 2014, and Foissner 2012;). II–V, frontoventral cirral cirral anlagen II–V. Broken lines in schematic illustrations (F–I) connect cirri which originate from the same anlage during morphogenesis. type species, the position of Schmidingerothrix in the trees somarginalia Berger, 2006 (mainly composed of oxytrichids published so far, is only a rough estimate. and uroleptids) in the tree published by Shao et al. (2014). Up to now, Schmidingerothrix species (including Para- Jung et al. (2015) found a sistergroup relationship between cladotricha salina, see above) have been included in at least Paracladotricha salina and S. salinarum. This group is sister 11 molecular trees. According to Foissner et al. (2014) and of a cluster mainly composed of amphisiellids and tra- Lu et al. (2015), S. salinarum branches off as single taxon chelostylids. According to Li et al. (2014), the cluster S. after the core urostylids and is sister of all other hypotrichs. salinarum + P.salina is sister of the core urostylids, however, Gonostomum species are distinctly separated from S. sali- with no support (17) in the ML tree. Heber et al. (2014) esti- narum in these trees. This branching pattern agrees with that mated the phylogenetic position of the psilotrichids. In their of the present analyses, where the three Schmidingerothrix tree, S. salinarum is sister of Gonostomum strenuum + G. taxa sequenced form a robustly supported cluster (Fig. 6). namibiense, but the support values are insigniﬁcant. In the By contrast, Paracladotricha salina (now S. salina, see Bayesian tree published by Bharti et al. (2015), P. salina + S. above) is, together with Gonostomum namibiense, sister of salinarum are related to Gonostomum species (including a large group composed of the core-urostylids and the Dor- Cotterillia bromelicola) and some species like Bistichella 36 X. Lu et al. / European Journal of Protistology 62 (2018) 24–42

Fig. 6. Maximum likelihood (ML) tree inferred from SSU rDNA sequences showing the systematic position of Schmidingerothrix elongata spec. nov. (bold) and the genus Schmidingerothrix (rectangle marked by arrow). Numbers near nodes are nonparametric bootstrap values for ML and posterior probability values for Bayesian inference (BI). “-” refers to disagreement in topology with the BI tree. All branches are drawn to scale. The names of the species are updated, that is, do not always agree with those in GenBank. We have omitted most names of higher taxa because, as in most (all?) other trees, the taxa are non-monophyletic. The scale bar corresponds to 0.02 expected substitutions per site. variabilis. In the analyses by Gao et al. (2016), dealing with cal cirrus, paroral membrane, dorsal kineties), perhaps due representatives from all main ciliate taxa, Paracladotricha to modiﬁcations caused by the extreme conditions present salina branches off somewhat earlier than the core urostylids in the highly saline (90‰!) soil of the type locality, i.e. in the tree based on SSU rDNA. According to Huang et al. the Etosha Pan, in Namibia. Foissner et al. (2014) proposed (2016), P. salina is sister of the genus Gonostomum, includ- an alternate scenario, namely, that taxa like Gonostomum, ing Cotterillia; the urostylids branch off later. By contrast, Oxytricha, and Uroleptus have evolved via Cladotricha from P. salina is more closely related to the urostylids than to the a Schmidingerothrix-like ancestor. gonostomatids in the trees of Luo et al. (2016, 2017). Shao et al. (2014) published a ﬁrst vague hypothesis about This overview shows that the phylogenetic position of the phylogenetic relationships between some taxa with a Schmidingerothrix estimated via gene sequence data is not gonostomatid oral apparatus. Their proposal basically sup- very stable and thus details should not be over-interpreted, ports the assumption of Foissner (2012) of a reduction of all the more as S. extraordinaria, the type species, is not the ciliature. Thus, we favour the hypothesis published in yet analysed (see above). Foissner (2012) hypothesized that the original description of Schmidingerothrix (Foissner 2012) S. extraordinaria is a “secondarily oligomerized” hypotrich, and by Shao et al. (2014) because the alternative discussed that is, it lost some common parts of the ciliature (e.g., buc- by Foissner et al. (2014) would require the assumption that X. Lu et al. / European Journal of Protistology 62 (2018) 24–42 37

Table 3. Morphogenetic comparison of the four Schmidingerothrix species.

Charactera S. extraordinaria S. salinarum S. salina S. elongata

UMA in proter Absent Present Present Absent FVA in proter, number 2 5 5 Mostly 3 FVA in opisthe, number 3 5 5 Mostly 4 FVA II in proter, origin De novo De novo De novo Intrakinetally FVA II in opisthe, origin De novo De novo De novo De novo FVA III in proter, origin Intrakinetally Intrakinetally Intrakinetally Intrakinetally FVA III in opisthe, origin De novo De novo De novo De novo FVA IV in proter, origin Na Intrakinetally Intrakinetally Intrakinetally FVA IV in opisthe, origin Na Intrakinetally Intrakinetally Intrakinetally FVA V in proter, origin Na Intrakinetally Intrakinetally Intrakinetally FVA V in opisthe, origin Na De novo Intrakinetally Intrakinetally FC derived from UMA, number 0 1 1 0 FC derived from FVA II, number 1 1 1 3 References 1 2 3 4

a Abbreviations: FC, frontal cirri; FVA, frontoventral cirri anlage; UMA, undulating membrane anlage (homologous to frontoventral cirri anlage I); II–V, frontoventral cirral anlagen II–V. Na, not applicable. References: 1 = Foissner (2012),2=Foissner et al. (2014; for a nomenclatural problem, see introduction), 3=Shao et al. (2014, 2017), 4 = present study. the ciliature of, for example, Gonostomum (bipolar dorsal Stokes, 1887, an oxytrichid (for revision, see Berger 1999), kineties with each one caudal cirrus; buccal cirrus and paroral in Bakuella Agamaliev & Alekperov, 1976, an urostylid (for membrane present) has evolved in the same way (that is, con- revision, see Berger 2006), or in Apogonostomum Foissner, vergently) as, for example, in the urostylids which branch off 2016, a gonostomatid (Foissner 2016). The agreements in earlier than Schmidingerothrix in some trees (e.g., Foissner some morphological features (oral apparatus, reduction of et al., 2014; Jung et al. 2015). By contrast, the hypothesis that some parts of ciliature) indicate that Schmidingerothrix is the last common ancestor of the Schmidingerothrix species a member of or at least closely related to the gonostom- has lost the above-mentioned structures needs no complex atids, an assumption supported by some gene sequence-based assumptions and is thus more parsimonious than the alterna- phylogenies where Schmidingerothrix or its junior synonym, tive (Foissner 2012; Shao et al. 2014). Paracladotricha, is closely related to Gonostomum (Heber Since Schmidingerothrix species lack a dorsal ciliature et al. 2014; Shao et al. 2014; Fig. 6). it is not possible to decide, via this morphological fea- The uncertainties in the estimation of the phylogenetic ture, whether this genus belongs to the Dorsomarginalia position of Schmidingerothrix are perhaps due to the low (presence of dorsomarginal kineties as morphological apo- number of gonostomatid/cladotrichid species (about five morphy; examples are the oxytrichids and the uroleptids) or without the three Schmidingerothrix species) analysed so far not (Berger 2006; p. 38; Berger 2008; p. 46). The discussion with molecular methods. According to the brief review below, of the gene sequence-based analyses (see above) shows that 56 species (including few incertae sedis) with a gonostomatid Schmidingerothrix branches off rather early in most studies, oral apparatus have been described so far. Perhaps the molec- indicating that it is a non-dorsomarginalian taxon (Fig. 6; ular analysis of more reliably identified species will improve e.g., Foissner et al., 2014; Shao et al. 2014). Foissner (2012; the veracity of the trees. p. 238, 250) supposed that it is an amphisiellid, but also discussed that it shows similarities with the gonostomatids, trachelostylids, and cladotrichids which were classified as Brief guide to hypotrichs with oral apparatus in supposed relatives by Foissner et al. (2014). The similar- Gonostomum-like pattern ity with the latter taxa is, inter alia or even mainly, due to the Gonostomum-like oral apparatus (for details on this Remarks. Some morphological features as well as some feature, see Berger 1999, 2011; Berger and Foissner 1997). phylogenetic analyses based on 18S rDNA indicate that In addition, several species of these taxa have reduced the Schmidingerothrix is a member of or at least closely related ciliature more or less distinctly. For example, Paragonosto- with the Gonostomatidae (see previous section). This group mum (Bigonostomum) species and Cladotricha similis have was revised by Berger (2011) who treated 33 species, a strongly reduced paroral membrane and lack transverse distributed in seven genera (two of them incertae sedis). How- cirri (Berger 2011; Foissner et al. 2002; Kumar and Foissner ever, since then rather many new species and genera have been 2016). The absence (loss) of caudal cirri, a main part of described, mainly by Foissner (2016). Thus, we provide an the dorsal ciliature, is a rather simple feature and is known updated list of genera (14) and species (58; including two for genera in most higher taxa, for example, in Tachysoma unpublished ones) with a Gonostomum-like oral apparatus as well as a key to genera to keep track of the taxa so far 38 X. Lu et al. / European Journal of Protistology 62 (2018) 24–42 described, especially because the differences are often rather body shape, length of adoral zone, bipartition of adoral zone, difficult to recognize. presence/absence of transverse and caudal cirri, and pres- There exist some further taxa whose oral apparatus resem- ence/absence and length of frontoventral cirral rows. In few bles that of the gonostomatids, for example, Kahliella Corliss, cases, the key is not completely unambiguous, for example, 1960 and Deviata Eigner, 1995. However, Kahliella belongs in Gonostomum, where G. sinicum forms the frontoventral- to the Dorsomarginalia, and molecular analyses indicate that transverse cirri from five or six anlagen (Lu et al. 2017) while both genera are neither closely related with Gonostomum nor the remaining species form them constantly from six anlagen but Heterogonostomum. In such cases, we recommend to follow both couplets.

List of genera and species with oral apparatus in Gonostomum-like pattern. The 14 genera are listed alpha- with Schmidingerothrix (e.g., Chen et al. 2015; Jung et al. betically, except for those classified as incertae sedis in the 2015; Li et al. 2014; Singh and Kamra 2014). For revision of gonostomatids by Berger (2011). The species assignable Kahliella and Deviata, see Berger (2011). are listed alphabetically within genera, except for the type Key to genera. Detailed live observations and/or protar- species, which is mentioned first. For each genus and species gol preparations are needed for the recognition of the generic you find a reference to the original description or to a detailed features. Important features for identification are, inter alia, X. Lu et al. / European Journal of Protistology 62 (2018) 24–42 39 revision. Note that synonyms of species and original combi- Berger (2011, p. 146). Further literature: Foissner (2016, nations are not mentioned. For a complete list of all these p. 647). (16) G. terrestre (Alekperov 2005) Berger, 2011. names for species described before 2010/2011, see Berger Remarks: For revision, see Berger (2011, p. 164); perhaps (2011). it belongs to Metagonostomum according to Foissner (2016, Apogonostomum Foissner, 2016; p. 611 p. 611). Incertae sedis in Gonostomum according to Berger Species assignable: (1) A. pantanalense Foissner, 2016; p. (2011): (17) Urosoma macrostomum Gellért, 1957. Remarks: 611 (type species). (2) A. vleiacola Foissner, 2016; p. 616. For revision, see Berger (2011, p. 168). Unpublished species: Cladotricha Gaievskaia, 1925; p. 259, 281. Remarks: For Gonostomum paronense Bharti et al., 2015. Remarks: The revision, see Berger (2011, p. 235). Name-bearing type genus “original description” of this species in an electronic-only of the Cladotrichidae Small & Lynn, 1985, a synonym of the work lacks the ZooBank registration; thus, not valid accord- Gonostomatidae according to Berger (2011, p. 51). ing to ICZN (2012), Article 8.5.3. Species assignable: (1) C. koltzowii Gaievskaia, 1925 (type Heterogonostomum Kumar & Foissner, 2016; p. 76 species). Remarks: For revision, see Berger (2011, p. 242). Species assignable: (1) H. salinarum Kumar & Foissner, (2) C. australis Blatterer & Foissner, 1988. Remarks: For 2016; p. 77 (type species, only 5 FVT-cirral anlagen). revision, see Berger (2011, p. 262). (3) C. chilensis Foissner, Metagonostomum Foissner, 2016; p. 611 2016; p. 541. (4) C. digitata Foissner, 2016; p. 550. (5) C. Species assignable: (1) M. gonostomoidum (Hemberger, halophila Wilbert, 1995. Remarks: For revision, see Berger 1985) Foissner, 2016 (type species). Remarks: Foissner (2011, p. 270). (6) C. sagittata Ruinen, 1938. Remarks: For (2016) made no formal combination (that is, term “comb. revision, see Berger (2011, p. 252). (7) C. sigmoidea Ruinen, nov.” not applied), but since this is the type species of 1938. Remarks: For revision, see Berger (2011, p. 254). (8) Metagonostomum the combination is likely made “automat- C. similis Kumar & Foissner, 2016; p. 66. Incertae sedis in ically”; in addition, Foissner (2016, p. 48) wrote, under Cladotricha according to Berger (2011): (9) Strongylidium the heading “new combinations”, that this species is trans- packii (Calkins in Pack, 1919) Kahl, 1932. Remarks: For ferred to Metagonostomum. For revision, see Berger (1999, revision see Berger (2011, p. 276). p. 392; Berger (2011, p. 158,asGonostomum gonosto- Cotterillia Foissner & Stoeck, 2011; p. 31 moidum (Hemberger 1985) Berger, 1999). According to Species assignable: (1) C. bromelicola Foissner & Stoeck, Foissner (2016), Gonostomum terrestre (see above) perhaps 2011; p. 31 (type species). Further literature: Berger (2011, also belongs to Metagonostomum. p. 57); Foissner (2016, p. 609). Neowallackia Berger, 2011; p. 280 Gonostomoides Foissner, 2016; p. 632 Species assignable: (1) N. franzi (Foissner 1982) Berger, Species assignable: (1) G. galapagensis Foissner, 2016; p. 2011 (type species). Remarks: For revision, see Berger (2011, 632 (type species). (2) G. bimacronucleatus Foissner, 2016; p. 281). (2) N. ghangriai (Kamra et al. 2008) Berger, 2011. p. 637. (3) G. caudatus Foissner, 2016; p. 640. (4) G. frater- Remarks: For revision, see Berger (2011, p. 295). (3) N. peter- culus Foissner, 2016; p. 644. gofi (Alekperov 2005) Berger, 2011. Remarks: For revision, Gonostomum Sterki, 1878; p. 36, 57. Remarks: For revi- see Berger (2011, p. 298). sion, see Berger (1999, p. 367), Berger (2011, p. 58). Paragonostomoides Foissner, 2016; p. 610 Name-bearing type genus of the Gonostomatidae Small & Species assignable: (1) P. minutum (Kamra et al. 2008) Lynn, 1985. Foissner, 2016; p. 48, 610, 905 (type species). Remarks: Species assignable: (1) G. affine (Stein 1859) Sterki, 1878 Foissner (2016) made no formal combination (that is, term (type species). Remarks: For revision, see Berger (1999, p. “comb. nov.” not applied), but since this is the type species 369), Berger (2011, p. 68). (2) G. albicarpathicum Vd’acnˇ y´ of Paragonostomoides, the combination is likely made “auto- & Tirjaková, 2006. Remarks: For revision, see Berger (2011, matically”. In addition, Foissner (2016, p. 48) wrote, under p. 135). (3) G. algicola Gellért, 1942. Remarks: For revision, the heading “new combinations”, that this species is trans- see Berger (2011, p. 116). (4) G. bromelicola Foissner, 2016; ferred to Paragonostomoides, and in the index he listed the p. 686. (5) G. caudatulum Foissner & Heber in Foissner, species as “minutum, Paragonostomoides”. For revision, see 2016; p. 660. (6) G. fraterculus Foissner, 2016; p. 696. Berger (2011, p. 204,asParagonostomum minutum). (7) G. halophilum Foissner, 2016; p. 651. (8) G. kuehnelti Paragonostomum Foissner et al., 2002; p. 819. Remarks: Foissner, 1987. Remarks: For revision, see Berger (1999, p. For revision, see Berger (2011, p. 172). Type species: P. 391), Berger (2011, p. 109). (9) G. lajacola Foissner, 2016; caudatum Foissner et al., 2002. p. 676. (10) G. multinucleatum Foissner, 2016; p. 679. (11) Subgenera assignable according to Berger (2011, p. G. namibiense Foissner et al., 2002. Remarks: For revision, 172): (1) Paragonostomum (Paragonostomum) Foissner see Berger (2011, p. 140). (12) G. salinarum Foissner, 2016; et al., 2002 (nominotypical subgenus). (2) Paragonostomum p. 658. (13) G. singhii Kamra et al., 2008. Remarks: Syn- (Bigonostomum) Berger, 2011. onymized with G. affine by Berger (2011, p. 69, 74, 85), Paragonostomum (Paragonostomum) Foissner et al., but after redescription considered as valid by Foissner (2016, 2002. Remarks: For revision, see Berger (2011, p. 176). p. 666). (14) G. sinicum Lu et al., 2017. (15) G. strenuum Species assignable: (1) P. (P.) caudatum Foissner et al., (Engelmann 1862) Sterki, 1878. Remarks: For revision, see 2002 in Berger (2011, p. 176) (type species). (2) P. (P.) aus- 40 X. Lu et al. / European Journal of Protistology 62 (2018) 24–42 traliense Foissner, 2016; p. 622 (original combination: P. Acknowledgements australiense Foissner, 2016); (3) P. (P.) rarisetum Foissner et al., 2002 in Berger (2011, p. 183). This work was supported by the Natural Science Foun- Paragonostomum (Bigonostomum) Berger, 2011; p. 184 dation of China (Projects numbers: 31772477, 31572247, Species assignable: (1) P. (B.) multinucleatum Foissner 31372148) and the Austrian Science Fund (FWF; project et al., 2002 in Berger (2011, p. 185) (type species). (2) P. numbers P23415-B17 to H. Berger). Our special thanks are (B.) binucleatum Foissner et al., 2002 in Berger (2011, p. given to Prof. Weibo Song (Ocean University of China, OUC) 192). for his insightful comments and suggestions during the prepa- Incertae sedis in Paragonostomum according to Berger ration of this manuscript. Many thanks are also due to Ms. (2011): P. simplex Foissner et al., 2005. Remarks: For revi- Zhao Lv for her kind help with gene sequencing. In addi- sion, see Berger (2011, p. 193). tion, we want to thank Dr. Thorsten Stoeck (University of Schmidingerothrix Foissner, 2012; p. 239 (new junior Kaiserslautern, Germany) for taxonomic advice. synonym: Paracladotricha Shao et al. 2017). Remarks: Name-bearing type genus of the Schmidingerotrichidae Foissner, 2012. Species assignable: (1) S. extaordinaria Foissner, 2012; p. References 239 (type species). (2) S. elongata spec. nov. (3) S. salina (Shao et al. 2017) comb. nov. (original combination: Para- Agamaliev, F.G., Alekperov, I.K., 1976. A new genus Bakuella cladotricha salina Shao et al., 2017; type species of junior (Hypotrichida) from the Caspian Sea and the Djei-ranbatansky synonym). Unpublished species: S. salinarum Foissner et al., water reservoir. Zool. Zh. 55, 128–131. 2014; p. 63, 73. Remarks: The “original description” in an Alekperov, I.K., 2005. An atlas of free-living ciliates. (Classes electronic-only work lacks the ZooBank registration (ICZN Kinetofragminophora, Colpodea, Oligohymenophora, Polyhy- 2012, Article 8.5.3); thus, not validly published. menophora). Borcali, Baku. 310 pp. (in Russian; translation of Wallackia Foissner, 1976; p. 390. Remarks: For revision, title by I. Alekperov). see Berger (2011, p. 206). Alfaro, M.E., Zoller, S., Lutzoni, F., 2003. Bayes or boot- Species assignable: (1) W.schiffmanni Foissner, 1976 (type strap? A simulation study comparing the performance of Bayesian Markov Chain Monte Carlo sampling and boostrap- species). Remarks: For revision, see Berger (2011, p. 209). ping in assessing phylogenetic confidence. Mol. Biol. Evol. 20, (2) W. bujoreani (Lepsi 1951) Berger & Foissner, 1989. 255–266. Remarks: For revision, see Berger (2011, p. 212). (3) W. ele- Berger, H., 1999. Monograph of the Oxytrichidae (Ciliophora, gans Foissner et al., 2002. Remarks: For revision, see Berger Hypotrichia). Monogr. Biol. 78, i–xiii, 1–1080. (2011, p. 227). Berger, H., 2006. Monograph of the Urostyloidea (Ciliophora, Hypotricha). Monogr. Biol. 85, i–xvi, 1–1304. Berger, H., 2008. Monograph of the Amphisiellidae and Trache- Incertae sedis in the Gonostomatidae lostylidae (Ciliophora, Hypotricha). Monogr. Biol. 88, i–xiii, 1–737. Remarks. The following two genera have been provision- Berger, H., 2011. Monograph of the Gonostomatidae and Kahliell- ally assigned to the gonostomatids by Berger (2011). Detailed idae (Ciliophora, Hypotricha). Monogr. Biol. 90, i–iv, 1–741. morphological and ontogenetic data (Trachelochaeta)as Berger, H., Foissner, W., 1989. Morphology and biometry of some well as molecular analyses (Trachelochaeta, Circinella) are soil hypotrichs (Protozoa: Ciliophora) from Europe and Japan. Bull. Br. Mus. Nat. Hist. (Zool.) 55, 19–46. needed for a more proper classification of these taxa. Berger, H., Foissner, W., 1997. Cladistic relationships and generic Circinella Foissner, 1994; p. 157. Remarks: For revision, characterization of oxytrichid hypotrichs (Protozoa, Ciliophora). see Berger (2011, p. 309). Arch. Protistenk. 148, 125–155. Species assignable: (1) C. arenicola Foissner, 1994 (type Bharti, D., Kumar, S., La Terza, A., 2015. Two gonostomatid ciliates species). Remarks: For revision, see Berger (2011, p. 317). from the soil of Lombardia, Italy; including note on the soil (2) C. filiformis (Foissner 1982) Foissner, 1994. Remarks: For mapping project. J. Eukaryot. Microbiol. 62, 762–772. revision, see Berger (2011, p. 333). (3) C. vettersi (Berger Blatterer, H., Foissner, W., 1988. Beitrag zur terricolen Cil- and Foissner 1989) Foissner, 1994. Remarks: For revision, iatenfauna (Protozoa: Ciliophora) Australiens. Stapfia 17, see Berger (2011, p. 327). 1–84. Trachelochaeta Srámek-Husek,ˇ 1954; p. 265. Remarks: Chen, L., Zhao, X., Ma, H., Warren, A., Shao, C., Huang, J., 2015. For revision, see Berger (2011, p. 300). Morphology, morphogenesis and molecular phylogeny of a soil ciliate, Pseudouroleptus caudatus caudatus Hemberger, 1985 Species assignable: (1) T. bryophila Srámek-Husek,ˇ 1954 (Ciliophora, Hypotricha), from Lhalu Wetland, Tibet. Eur. J. (type species). Remarks: For revision, see Berger (2011, p. Protistol. 51, 1–14. 303). Incertae sedis in Trachelochaeta according to Berger Chen, L., Lv, Z., Shao, C., Al-Farraj, S.A., Song, W., Berger, H., (2011): (2) Oxytricha (Opisthotricha) elongata Grandori and 2016. Morphology, cell division, and phylogeny of Uroleptus Grandori, 1934. Remarks: For revision, see Berger (2011, p. longicaudatus (Ciliophora Hypotricha), a species of the Urolep- 306). tus limnetis complex. J. Eukaryot. Microbiol. 63, 349–362. X. Lu et al. / European Journal of Protistology 62 (2018) 24–42 41

Corliss, J.O., 1960. The problem of homonyms among generic Ciliophora, Scuticociliatia) suggest its close relationship with names of ciliated protozoa, with proposal of several new names. thigmotrichids. Mol. Phylogenet. Evol. 75, 219–226. J. Protozool. 7, 269–278. Gao, F., Warren, A., Zhang, Q., Gong, J., Miao, M., Sun, P., Xu, D., Eigner, P.,1995. Divisional morphogenesis in Deviata abbrevescens Huang, J., Yi, Z., Song, W., 2016. The all-data-based evolution- nov. gen., nov. spec., Neogeneia hortualis nov. gen., nov. spec., ary hypothesis of ciliated protists with a revised classification and Kahliella simplex (Horvath) Corliss and redefinition of the of the phylum Ciliophora (Eukaryota, Alveolata). Sci. Rep. 6, Kahliellidae (Ciliophora, Hypotrichida). Eur. J. Protistol. 31, 24874 (14 pages). 341–366. Gellért, J., 1942. Életegyüttes a fakéreg zöldporos bevonatában Engelmann, T.W., 1862. Zur Naturgeschichte der Infusionsthiere. (Lebensgemeinschaft in dem grünpulverigen Überzug der Z. Wiss. Zool. 11, 347–393. Baumrinde). Acta Sci. Math. Nat., Univ. Francisco-Josephina Foissner, W., 1976. Wallackia schiffmanni nov. gen. nov. spec. Kolozsvár 8, 1–36. (Ciliophora, Hypotrichida) ein alpiner hypotricher Ciliat. Acta Gellért, J., 1957. Néhány hazai lomblevelü és tülevelü erdö talajá- Protozool. 15, 387–392. nak ciliáta-faunája Ciliatenfauna im Humus einiger ungarischen Foissner, W., 1982. Ökologie und Taxonomie der Hypotrichida Laub- und Nadelholzwälder. Annls Inst. biol. Tihany 24, 11–34. (Protozoa: Ciliophora) einiger österreichischer Böden. Arch. Grandori, R., Grandori, L., 1934. Studî sui protozoi del terreno. Protistenk. 126, 19–143. Boll. Lab. Zool. agr. Bachic. R. Ist. sup. agr. Milano 5, 1–341, Foissner, W., 1987. Neue terrestrische und limnische Ciliaten (Pro- Tavole I–XIV. tozoa, Ciliophora) aus Österreich und Deutschland. Sber. Öst. Hall, T.A., 1999. BioEdit: a user-friendly biological sequence Akad. Wiss., Math.-naturw. Kl., Abt. I 195, 217–268 (year 1986). alignment editor and analysis program for Windows 95/98/NT. Foissner, W., 1994. Morphology and morphogenesis of Circinella Nucleic Acids Symp. Ser. 41, 95–98. arenicola nov. gen. nov. spec., a cephalized hypotrich (Cilio- Heber, D., Stoeck, T., Foissner, W., 2014. Morphology and onto- phora, Hypotrichida) from sand dunes in Utah, USA. Eur. J. genesis of Psilotrichides hawaiiensis nov. gen., nov. spec. Protistol. 30, 156–170. and molecular phylogeny of the Psilotrichidae (Ciliophora, Foissner, W., 2012. Schmidingerothrix extraordinaria nov. gen. Hypotrichia). J. Eukaryot. Microbiol. 61, 260–277. nov. spec., a secondarily oligomerized hypotrich (Ciliophora, Hemberger, H., 1985. Neue Gattungen und Arten hypotricher Cili- Hypotricha, Schmidingerotrichidae nov. fam.) from hypersaline aten. Arch. Protistenk. 130, 397–417. soils of Africa. Eur. J. Protistol. 48, 237–251. Hentschel, E.J., Wagner, G.H., 1996. Zoologisches Wörterbuch. Foissner, W., 2014. An update of ‘basic light and scanning electron Tiernamen, allgemeinbiologische, anatomische, physiologische microscopic methods for taxonomic studies of ciliated protozoa’. Termini und Kurzbiographien, 6th ed. Jena, Gustav Fischer Ver- Int. J. Syst. Evolut. Microbiol. 64, 271–292. lag. Foissner, W., 2016. Terrestrial and semiterrestrial ciliates (Proto- Hillis, D.M., Bull, J.J., 1993. An empirical test of bootstrapping as a zoa, Ciliophora) from Venezuela and Galápagos. Denisia 35, method for assessing confidence in phylogenetic analysis. Syst. 1–912. Biol. 42, 182–192. Foissner, W., Al-Rasheid, K., 2006. A unified organization of the sti- Huang, J., Luo, X., Bourland, W.A., Gao, F., Gao, S., 2016. chotrichine oral apparatus, including a description of the buccal Multigene-based phylogeny of the ciliate families Amphisiel- seal (Ciliophora: Spirotrichea). Acta Protozool. 45, 1–16. lidae and Trachelostylidae (Protozoa: Ciliophora: Hypotrichia). Foissner, W., Stoeck, T., 2011. Cotterillia bromelicola nov. gen. Mol. Phylogenet. Evolut. 101, 101–110. nov. spec., a gonostomatid ciliate (Ciliophora, Hypotricha) from ICZN (International Commission on Zoological Nomenclature), tank bromeliads (Bromeliaceae) with de novo originating dorsal 1999. International Code of Zoological Nomenclature. Interna- kineties. Eur. J. Protistol. 47, 29–50. tional Trust for Zoological Nomenclature, London, 306 p. Foissner, W., Agatha, S., Berger, H., 2002. Soil ciliates (Protozoa, ICZN (International Commission of Zoological Nomenclature), Ciliophora) from Namibia (Southwest Africa), with emphasis on 2012. Amendment of Articles 8, 9, 10, 21 and 78 of the Inter- two contrasting environments, the Etosha region and the Namib national Code of Zoological Nomenclature to expand and refine Desert. Part I: Text and line drawings. Part II: Photographs. methods of publication. Bull. Zool. Nomencl. 69, 161–169. Denisia 5, 1–1459. Jung, J.-H., Park, K.-M., Min, G.-S., Berger, H., Kim, S., 2015. Foissner, W., Berger, H., Xu, K., Zechmeister-Boltenstern, S., 2005. Morphology and molecular phylogeny of an Antarctic popula- A huge, undescribed soil ciliate (Protozoa: Ciliophora) diversity tion of Paraholosticha muscicola (Kahl, 1932) Wenzel, 1953 in natural forest stands of Central Europe. Biodivers. Conserv. (Ciliophora, Hypotricha). Polar Sci. 9, 374–381. 14, 617–701. Kahl, A., 1932. Urtiere oder Protozoa I: Wimpertiere oder Ciliata Foissner, W., Filker, S., Stoeck, T., 2014. Schmidingerothrix sali- (Infusoria) 3. Spirotricha. Tierwelt Dtl. 25, 399–650. narum nov. spec. is the molecular sister of the large oxytrichid Kamra, K., Kumar, S., Sapra, G.R., 2008. Species of Gonostomum clade (Ciliophora, Hypotricha). J. Eukaryot. Microbiol. 61, and Paragonostomum (Ciliophora Hypotrichida, Oxytrichidae) 61–74. from the Valley of Flowers, India, with descriptions of Gonos- Gaievskaia, N., 1925. Sur deux nouveaux infusoires des mares salées tomum singhii sp. nov., Paragonostomum ghangriai sp. nov. – Cladotricha koltzowii, nov. gen. nov. sp. et Palmarium salinum and Paragonostomum minuta sp. nov. Indian J. Microbiol. 48, nov. gen. nov. sp. Russk. Arkh. Protist. 4, 255–288, Planches XV, 372–388. XVI. Kumar, S., Foissner, W., 2016. High cryptic soil ciliate (Ciliophora, Gao, F., Wang, P., Katz, L.A., Gao, S., Song, W., 2014. Hypotrichida) diversity in Australia. Eur. J. Protistol. 53, 61–95. Multigene-based phylogenetic analyses of cyclidiids (Protista, Lepsi, I., 1951. Modificarea faunei de protozoare tericole, prin irigatii agricole (La modification de la faune des protozoaires terricoles par des irrigations agricoles). Buletin sti. Acad. Repub. 42 X. Lu et al. / European Journal of Protistology 62 (2018) 24–42

pop rom., Seria: Geologie, geografie, biologie, stiinte tehnice si Ronquist, F., Huelsenbeck, J.P., 2003. MrBayes 3: Bayesian phy- agricole. Sectiunea de stiinte biologice, agronomice, geologice logenetic inference under mixed models. Bioinformatics 19, si geografice 3, 513–523. 1572–1574. Li, F., Lv, Z., Yi, Z., Al-Farraj, S.A., Al-Rasheid, K.A.S., Shao, Ruinen, J., 1938. Notizen über Ciliaten aus konzentrierten C., 2014. Taxonomy and phylogeny of two species of the genus Salzgewässern. Zoöl. Meded., Leiden 20, 243–256. Deviata (Protista Ciliophora) from China, with description of a Shao, C., Li, L., Zhang, Q., Song, W., Berger, H., 2014. Molecular new soil form, Deviata parabacilliformis spec. nov. Int. J. Syst. phylogeny and ontogeny of a new ciliate genus, Paracladotricha Evol. Microbiol. 64, 3775–3785. salina n. g., n. sp. (Ciliophora, Hypotrichia). J. Eukaryot. Micro- Lu, X., Shao, C., Yu, Y., Warren, A., Huang, J., 2015. Reconsidera- biol. 61, 371–380. tion of the ‘well-known’ hypotrichous ciliate Pleurotricha curdsi Shao, C., Li, L., Zhang, Q., Song, W., Berger, H., 2017. Corrigendum (Shi et al. 2002) Gupta et al., 2003 (Ciliophora, Sporadotrichida), to Molecular phylogeny and ontogeny of a new ciliate genus, with notes on its morphology, morphogenesis and molecular Paracladotricha salina n. g., n. sp. (Ciliophora, Hypotrichia) by phylogeny. Int. J. Syst. Evol. Microbiol. 65, 3216–3225. Shao et al. 2014. J. Eukaryot. Microbiol. 64, 901–902. Lu, X., Huang, J., Shao, C., Al-Farraj, S.A., Gao, S., 2017. Singh, J., Kamra, K., 2014. Molecular phylogeny of an Indian Morphology and morphogenesis of a novel saline soil hypotri- population of Kleinstyla dorsicirrata (Foissner, 1982) Foiss- chous ciliate, Gonostomum sinicum nov. spec. (Ciliophora, ner et al., 2002. comb. nov. (Hypotrichia, Oxytrichidae): an Hypotrichia, Gonostomatidae), including a report on the small oxytrichid with incomplete dorsal kinety fragmentation. J. subunit rDNA sequence. J. Eukaryot. Microbiol. 64, 632–646. Eukaryot. Microbiol. 61, 630–636. Luo, X., Fan, Y., Hu, X., Miao, M., Al-Farraj Song, W., 2016. Mor- Small, E.B., Lynn, D.H., 1985. Phylum Ciliophora Doflein, 1901. phology, ontogeny, and molecular phylogeny of two freshwater In: Lee, J.J., Hutner, S.H., Bovee, E.C. (Eds.), An Illustrated species of Deviata (Ciliophora, Hypotrichia) from Southern Guide to the Protozoa. Society of Protozoologists, Lawrence, China. J. Eukaryot. Microbiol. 63, 771–785. pp. 393–575. Luo, X., Gao, F., Yi, Z., Pan, Y., Al-Farraj, S.A., Warren, A., Srámek-Husek,ˇ R., 1954. Neue und wenig bekannte Ciliaten aus der 2017. Taxonomy and molecular phylogeny of two new brack- Tschechoslowakei und ihre Stellung im Saprobiensystem. Arch. ish hypotrichous ciliates, with the establishment of a new genus Protistenk. 100, 246–267. (Ciliophora, Spirotrichea). Zool. J. Linnean Soc. 179, 475–491. Stamatakis, A., Hoover, P., Rougemont, J., 2008. A rapid bootstrap Lynn, D.H., 2008. The Ciliated Protozoa: Characterization, Classi- algorithm for the RAxML Web servers. Syst. Biol. 57, 758–771. fication, and Guide to the Literature, 3rd ed. Springer, Dordrecht. Stein, F., 1859. Der Organismus der Infusionsthiere nach eige- Medlin, L., Elwood, H.J., Stickel, S., Sogin, M.L., 1988. The nen Forschungen in systematischer Reihenfolge bearbeitet. characterization of enzymatically amplified eukaryotic 16S-like I. Abtheilung. Allgemeiner Theil und Naturgeschichte der rRNA-coding regions. Gene 71, 491–499. hypotrichen Infusionsthiere. Engelmann, Leipzig. Miller, M.A., Pfeiffer, W., Schwartz, T., 2010. “Creating the Sterki, V., 1878. Beiträge zur Morphologie der Oxytrichinen. Z. CIPRES Science Gateway for inference of large phylogenetic Wiss. Zool. 31, 29–58. trees” in Proceedings of the Gateway Computing Environments Stokes, A.C., 1887. Some new hypotrichous infusoria from Amer- Workshop (GCE), 14 Nov. 2010, New Orleans, LA. p. 1–8. ican fresh waters. Ann. Mag. Nat. Hist. Ser. 5 (20), 104–114. Nebel, M., Pfabel, C., Stock, A., Dunthorn, M., Stoeck, T., 2011. Tamura, K., Dudley, J., Nei, M., Kumar, S., 2007. MEGA4: molecu- Delimiting operational taxonomic units for assessing ciliate envi- lar evolutionary genetics analysis (MEGA) software version 4.0. ronmental diversity using small-subunit rRNA gene sequences. Mol. Biol. Evol. 24, 1596–1599. Environ. Microbiol. Rep. 3, 154–158. Vd’acnˇ y,´ P., Rajter, L., 2015. Reconciling morphological and molec- Nylander, J.A.A., 2004. MrModeltest 2.2. Program distributed by ular classification of predatory ciliates: evolutionary taxonomy the author. Evolutionary Biology Centre, Uppsala University, of dileptids (Ciliophora, Litostomatea, Rhynchostomatia). Mol. Uppsala, Sweden. Phylogenet. Evol. 90, 112–128. Pack, D.A., 1919. Two ciliata of Great Salt Lake. Biol. Bull. Mar. Vd’acnˇ y,´ P., Tirjaková, E., 2006. A new soil hypotrich ciliate (Proto- Biol. Lab., Woods Hole 36, 273–282. zoa, Ciliophora) from Slovakia: Gonostomum albicarpathicum Page, R.D.M., 1996. TreeView: an application to display phyloge- nov. sp. Eur. J. Protistol. 42, 91–96. netic trees on personal computers. Comput. Appl. Biosci. 12, Wilbert, N., 1975. Eine verbesserte Technik der Protargolimpräg- 357–358. nation für Ciliaten. Mikrokosmos 64, 171–179. Penn, O., Privman, E., Ashkenazy, H., Landan, G., Graur, D., Pupko, Wilbert, N., 1995. Benthic ciliates of salt lakes. Acta Protozool. 34, T., 2010a. GUIDANCE: a web server for assessing alignment 271–288. confidence scores. Nucleic Acids Res. 38, W23–W28. Penn, O., Privman, E., Landan, G., Graur, D., Pupko, T., 2010b. An alignment confidence score capturing robustness to guide tree uncertainty. Mol. Biol. Evol. 27, 1759–1767.