taxonID	type	description	language	source
FE3787A3FFB4FFC091BB64F8B397FD00.taxon	diagnosis	Diagnosis. Body size in vivo 40 – 65 × 25 – 35 µm, oval in outline. Minute cortical granules densely arranged between ciliary rows. One macronucleus and usually two micronuclei. Adoral zone composed of about 19 membranelles. About eight cirral rows; the first cirri of the rightmost four rows enlarged significantly; about six transverse cirri, arranged in two rows posterior to the second and third inner cirral row; about four migratory cirri and eight dorsal kineties. Seawater habitat.	en	Hu, Yue, Suzuki, Toshikazu, Hu, Xiao-Zhong (2025): Taxonomic study on marine ciliates from Japan, with description of a new species, Caryotricha orientalis nov. spec. (Alveolata: Ciliophora). Zootaxa 5584 (2): 243-258, DOI: 10.11646/zootaxa.5584.2.5, URL: https://doi.org/10.11646/zootaxa.5584.2.5
FE3787A3FFB4FFC091BB64F8B397FD00.taxon	materials_examined	Type locality. New Fishing Port of Nagasaki, Japan.	en	Hu, Yue, Suzuki, Toshikazu, Hu, Xiao-Zhong (2025): Taxonomic study on marine ciliates from Japan, with description of a new species, Caryotricha orientalis nov. spec. (Alveolata: Ciliophora). Zootaxa 5584 (2): 243-258, DOI: 10.11646/zootaxa.5584.2.5, URL: https://doi.org/10.11646/zootaxa.5584.2.5
FE3787A3FFB4FFC091BB64F8B397FD00.taxon	etymology	Etymology. The species-group name orientalis recalls the fact that this species was first collected from oriental (Japanese) coastal waters. Ecological data. Water temperature 23.7 ºC, pH 8.2, salinity 34.0 ‰, DO 5.82 mg / L. Deposition of specimens. One protargol slide (registration number: NagC 2003101601) containing the holotype and paratype specimens was deposited at the Marine Biological Museum, Chinese Academy of Sciences, China. Three other slides with paratype specimens (registration numbers: NagC 2003101602, - 03, - 04) were deposited in the Laboratory of Protozoology, Ocean University of China, Qingdao, China.	en	Hu, Yue, Suzuki, Toshikazu, Hu, Xiao-Zhong (2025): Taxonomic study on marine ciliates from Japan, with description of a new species, Caryotricha orientalis nov. spec. (Alveolata: Ciliophora). Zootaxa 5584 (2): 243-258, DOI: 10.11646/zootaxa.5584.2.5, URL: https://doi.org/10.11646/zootaxa.5584.2.5
FE3787A3FFB4FFC091BB64F8B397FD00.taxon	description	Description. Body size in vivo 40 – 65 × 25 – 35 µm, with the ratio of body length to body width ca 1.5 – 1.8; oval in outline with anterior end narrowed and posterior end round (Figs. 1 A, 2 A – F); dorsoventrally somewhat flattened, with ventral side flat and dorsal side convex. Buccal field dominant, extending about 65 % of the cell length in vivo (Figs. 1 A, 2 F and H). Pellicle rigid, with cortical granules rod-shaped, about 1 µm long and 0.2 – 0.25 µm wide, arranged perpendicularly underneath in dense packs between cirral or ciliary rows (Figs. 1 B, C, 2 G, I). Cytoplasm full of many inclusions and several food vacuoles containing diatoms, especially in the posterior half of the cell, rendering cell opaque under low magnification except the transparent buccal cavity that is broad, about half of body width with the margin of buccal lip concaved where cirri are located (Figs. 1 A, 2 A – F, H). Macronucleus globular to ellipsoidal in shape, distributed in the anterior half of the cell, up to 15 µm across in vivo (Figs. 1 A, D, 2 C, F, I); mostly two, rarely one or three micronuclei recognized in stained specimens, globular to slightly oval, about 1.6 µm long (Figs. 1 D, 2 K). No contractile vacuole observed. Locomotion moderately quick, either by swimming around the body axis or crawling rapidly on the substrate. Adoral zone of membranelles slightly curved, extending about 68 % of body length in protargol preparations and consisting of about 19 membranelles (Figs. 1 D, 2 J; Table 1). Endoral membrane double-rowed in zig-zag pattern, while paroral membrane consisting of obliquely arranged rows of kinetosomes and three or four kinetosomes in each row; both being almost equally long and parallel to each other (Figs. 1 D, 2 J). On both ventral and dorsal sides, most cirri arranged in 8 or 9 longitudinally curved rows, of which the longest one extends to mid-body (Figs. 1 D, E, 2 J, L). Cirri generally uniform and non-grouped with exception of transverse cirri that are generally arranged in two short rows behind the second and third inner cirral rows (Figs. 1 D, 2 J), with cilia about 18 µm long in vivo. The bases of transverse cirri mostly long rectangular and larger than other cirri and thus clearly recognizable. Always the first cirrus of each of the rightmost four cirral rows on dorsal side conspicuously larger than other cirri (Figs. 1 E, L). One short migratory row posterior to buccal field, comprising about four cirri (Figs. 1 D, 2 J), with cilia 10 µm long in vivo. About eight dorsal kineties on the dorsal and ventrolateral sides, with dikinetids sparsely arranged; each dikinetid bearing two cilia, about 3 µm long in vivo (Figs. 1 D, E, 2 I, J, L). The leftmost dorsal kinety commencing subapically on dorsal side and extending to ventral side; the middle kineties shortened anteriorly and the rightmost one on dorsal side continuing anteriorly with the rightmost cirral row (counted clockwise from ventral side to dorsal side), thus making a mixed structure. Species identification of Japan form. As regards the simple, ancestral pattern of the dorsal dikinetids (both basal bodies of each dikinetid bearing one short cilium), uniform distribution of most cirri on the ventral and dorsolateral sides, and the presence of a short migratory row just behind peristome as well as rod-shaped cortical granules, the Japan form undoubtedly belongs to the genus Caryotricha. Up to now, there are only four species reported in Caryotricha, i. e., C. convexa Kahl, 1932 (type species), C. minuta (Xu et al., 2008) Miao et al., 2009, C. rariseta Jiang et al., 2013, and C. sinica Lian et al., 2020 (Kahl 1932; Xu et al. 2008; Miao et al. 2009; Jiang et al. 2013; Lian et al. 2020; Table 2). No morphometric data are available for C. convexa. According to the description by Kahl (1932) and illustration of Borror (1972), the cirral rows of C. convexa extend to the posterior end of the cell, which is very distinct from those of the present form (vs. about half of body length). Among the remaining three congeners, C. minuta is most similar to the present form in terms of body size and shape, the number and arrangement of transverse cirri, and the number of dorsal kineties (Xu et al. 2008; Miao et al. 2009; Tables 1 and 2), however, the latter can be clearly distinguished by a combination of the following morphological characters: relative shorter adoral zone (ca. 68 % of body length vs. on average 80 % of body length in C. minuta), the longest cirral row extending to mid-body with about 15 cirri (vs. two-thirds of body length, composed of 21 cirri for the holotype), the number and arrangement of migratory cirri (on average 4, sparsely spaced vs. 7 or 8, close-set) and lower number of adoral membranelles (17 – 20, on average 19 vs. 22 – 27, on average 25 in the Korea population, and 22 – 25, on average 23 in the China population). Furthermore, for the Japan isolates, the first cirrus of each of the rightmost four cirral rows has extremely larger base than others, a character not described for C. minuta. Actually, according to line illustration (Fig. 1 g) and micrograph (Fig. 2 n) given for China population of C. minuta, the first cirrus of each of the rightmost six cirral rows is slightly enlarged when compared with the remain cirri in these rows (Miao et al. 2009). Unfortunately, this feature cannot be determined for the Korea (type) population due to excessive staining. Additionally, the current form has lower number of cirral rows (8 – 9, mostly 8 vs. 9 – 12, on average 10, and invariably 11) and fewer cirri in cirral rows 1 – 3 (3 – 5, ca. 4; 5 – 7, on average 6; and 5 – 9, on average 8 vs. 7, 11 – 13, and 10 – 13 counted from illustrations; Tables 1 and 2). Therefore, both forms cannot be conspecific from morphological perspective. Xu et al. (2008) described rod-shaped, 3 – 4 µm long extrusomes, which cannot be justified owing to the lack of micrographs of live ciliates; the colorless cortical granules illustrated are ca. 1 µm long (estimated from Figure 6 in the original publication), similar to cortical granules in the present form in the length and arrangement mode, but they are different in the shape (ellipsoidal vs. rod-shaped). Miao et al. (2009) recorded bar-shaped cortical ‘ granules’ up to 5 µm long, which was, however, not substantiated by a micrograph provided (Figure 2 g in the original paper); according to the size of macronucleus (ca. 25 µm across), these cortical granules are about 1 µm long. These cortical granules in C. minuta show the same pattern as in the current form and two other congeners with data available (Jiang et al. 2013, Lian et al. 2020), suggesting it might be a plesiomorphic character for the genus Caryotricha. Caryotricha sinica Lian et al., 2020 is also closely related to the present form in terms of body size and shape, the numbers of adoral membranelles and cirral rows as well migratory cirri, but both can differ by the arrangement and number of transverse cirri (3 or 4 in a single pseudo-row in the former vs. 5 – 7, two- rowed in the latter), the number of dorsal kineties (5 vs. 8), and the number and arrangement of cirri in the rightmost cirral row (17 – 30, distinctly smaller and more narrowly spaced than others vs. 9 – 12, usual as others (Lian et al. 2020). Our form can be separated from C. rariseta Jiang et al., 2013 by having higher numbers of adoral membranelles (17 – 20, on average 19 vs. 13 – 15) and dorsal kineties (ca. 8 vs. 5), and in the number and arrangement of transverse cirri (5 – 7, arranged in two rows vs. 3 in a pseudo-row) (Jiang et al. 2013). Conclusively, the present form cannot be any extant species in the genus and a new species has to be proposed for it.	en	Hu, Yue, Suzuki, Toshikazu, Hu, Xiao-Zhong (2025): Taxonomic study on marine ciliates from Japan, with description of a new species, Caryotricha orientalis nov. spec. (Alveolata: Ciliophora). Zootaxa 5584 (2): 243-258, DOI: 10.11646/zootaxa.5584.2.5, URL: https://doi.org/10.11646/zootaxa.5584.2.5
FE3787A3FFB3FFCE91BB62CCB143FDF0.taxon	description	Description. Only several protargol-stained specimens are available, which still allows for the identification of species. Cell size 67 – 90 × 42 – 68 μm after protargol staining, elongate rectangular in outline (Fig. 3). Adoral zone of membranelles occupying 55 – 60 % of body length, divided into two parts and composed of 33 – 36 membranelles: about six membranelles in apical part, positioned on dorsal side and widely arranged; the remaining on ventral side; kinetosomal structure typical of euplotid (Fig. 3 A, C, G). Undulating membranes composed of paroral and endoral membranes, which are of about the same length, spatially intersecting (Fig. 3 A, G), but the detailed structure undetermined. Somatic ciliature basically stable. Nine or ten relatively weak frontoventral cirri, about 30 μm long, sparsely distributed throughout the frontal region; one of them located close to and ahead of transverse cirri (Fig. 3 A, C, H). Invariably, there are five transverse cirri, with the left four cirri markedly large, and the rightmost one rather small, aligned transversely; the cilia about 50 μm long (Fig. 3 A, C, I). Two or three left marginal cirri shifted posteriorly when compared to members of the genus Diophrys (Fig. 3 A, C, F). Invariably three caudal cirri on dorsal side of right cell margin, prominent because of hook-like (Fig. 3 B, C, J). Constantly six dorsal kineties on dorsal side, with 17 – 20, 26 – 28, 21 – 25, 24 – 28, 21 – 22, and 14 – 17 dikinetids (counted from left to right), respectively; all kineties dikinetidal, closely spaced at the anterior end and loosely spaced at the posterior end, and conspicuously shortened posteriorly except the second one, which is the longest and extends to the rear end of cell (Fig. 3 B D); only the anterior basal body of each dikinetid bearing a 4 μm long cilium. Invariably two ellipsoidal macronuclear nodules, 18 – 20 × 8 – 10 μm, which are connected by a thin fiber (Fig. 3 B, E); micronucleus not observed in preparations. Fine cortical granules densely aligned in rows along dorsal kineties on dorsal side (not shown). Ecological data. Water temperature 27.6 ºC, pH 8.2, salinity 32.8 ‰, DO 7.6 mg / L. Morphological comparison. This species was originally described by Mansfeld (1923) under the name Diophrys irmgard, which was transferred to the newly erected genus Paradiophrys by Jankowski (1978). Hill and Borror (1992) first studied several USA isolates of Paradiophrys irmgard using the protargol staining method, which revealed considerable variability in body size, and the number and distribution of frontoventral cirri and transverse cirri (Table 3), but relatively minor difference in cell shape and the arrangement of left marginal cirri and dorsal kineties among populations. Song et al. (2007) redescribed it as Diophrys irmgard and provided morphometric data based on a China population, compiled in the monograph by Song et al. (2009). The present form investigated is very similar to type population in body shape and size after fixation, the number and the positioning of cirri, especially left marginal cirri, so it can be identified as Paradiophrys irmgard, a new record for Japan. With regards to ciliature, the present form is very similar to Qingdao and USA populations in: (i) the number of adoral membranelles (33 – 36 vs. 25 – 39); (ii) posteriorly shifted left marginal cirri; and (iii) constantly two macronuclear nodules and six dorsal kineties. Nevertheless, minor differences exist among these isolates in terms of the numbers of frontoventral cirri and transverse cirri as well as left marginal cirri, variable characters commonly recognized within some species of Diophrys - complex (Song et al. 2007; Hu 2008; Jiang et al. 2011; Luo et al. 2014). Hill and Borror (1992) did not provide the details of paroral and endoral membranes, but described ‘ a monokinetid endoral row of cilia and a large polykinetid paroral membrane extend from the cytostome anteriorly along the right edge of the buccal overture’, inferring that both are equal long as shown in Paradiophrys multinucleata and Diophrys species; according to the illustrations, it may occupy about 3 / 4 of the length of buccal field. Therefore, all these divergences discussed above could be accepted as intraspecific variation. Song et al. (2007) recorded an extremely reduced endoral membrane in their form, which might represent a distinct species in the genus. However, as regards its high similarity with populations of P. irmgard reported previously and in this study, it might be conservatively considered as a population of the species. Within Paradiophrys, only three congeners can be compared with the Nagasaki population of Paradiophrys irmgard (Table 3). P. kahli (Dragesco, 1963) Jankowski, 1978 has only been described once without details of the ciliature (Dragesco 1963), but can be distinguished from P. irmgard by its unsculptured surface, small buccal field, slender body shape, and most frontoventral cirri clustered together right of buccal field as well as single caudal cirrus. P. multinucleata (Hartwig, 1973) Jankowski, 1978 was first reported by Hartwig (1973) to have many macronuclear nodules clustered. This species was later described to possess six frontoventral and four transverse cirri, 20 - 30 macronuclear fragments and a dorsal ridge along the right side of the cell (Hill & Borror 1992), and thus cannot be confused with P. irmgard. The Nagasaki isolate of P. irmgard differs from Paradiophrys zhangi Jiang et al., 2011 by more adoral membranelles (33 – 36 vs. 26 – 30), endoral membrane (nearly equal to paroral membrane vs. highly reduced, one-third of paroral membrane in length), more frontoventral cirri (9 or 10, sparsely arranged vs. usually 7, two-grouped), and more dikinetids (26 – 28 vs. 21, counted from illustration of holotype) in the second dorsal kinety (Jiang et al. 2011).	en	Hu, Yue, Suzuki, Toshikazu, Hu, Xiao-Zhong (2025): Taxonomic study on marine ciliates from Japan, with description of a new species, Caryotricha orientalis nov. spec. (Alveolata: Ciliophora). Zootaxa 5584 (2): 243-258, DOI: 10.11646/zootaxa.5584.2.5, URL: https://doi.org/10.11646/zootaxa.5584.2.5
FE3787A3FFBDFFCD91BB64E2B7D8FBDC.taxon	description	Description. Cell size in vivo 60 – 85 × 25 – 40 μm (estimated from live and stained specimens), elongate lanceolate with anterior end tapering and posterior end round; length: width ratio ca. 2.5 – 3: 1 (Fig. 5 A, B). Flexible but not distinctly contractile. Cytoplasm greyish at low magnification, and the posterior cell portion often packed with different sized globules. Constantly two ellipsoid macronuclear nodules distinctly separated, 11 – 21 × 8 – 13 μm after protargol staining, with one spherical micronucleus between (Figs. 4 B, 5 E and G). Movement characteristic, that is, often immobile for several minutes with radiating distal adoral membranelles lying, then jumping suddenly. Buccal field less than 30 % of body length (Fig. 5 A, B); buccal cavity rather short and narrow; cytopharyngeal fibers extending posteriorly to mid-body (Fig. 5 C). Adoral zone of membranelles divided into two parts: usually five apical membranelles with cilia up to 25 μm long, spine-shaped and radiating (Fig. 5 A – C), proximal part with nine or ten membranelles with short cilia, the posterior-most two often covered by lip, detached from other proximal membranelles in protargol preparations (Figs. 4 A, 5 C, G). Undulating membranes located at the mid-portion of the buccal field, parallel to each other, and monokinetidal, with paroral membrane ahead of endoral membrane, and the former about half of the latter in length (Figs. 4 A, 5 G). All cirri relatively fine, 15 – 20 μm long, except transverse cirri that are strong with cilia up to 25 μm long, projecting beyond the rear end of body (Fig. 5 A). Cirral pattern rather stable (Figs. 4 A, 5 G). Cirri in frontal field arranged in fixed pattern but shifted backward when compared with typical oxytrichids, of which three frontal cirri located near distal end of adoral zone, one buccal cirrus behind endoral membrane, and four frontoventral cirri behind the level of cytostome. Other cirri on ventral side including three postoral ventral cirri (about in mid body), and two pretransverse ventral cirri just anterior to five transverse cirri. The left marginal row comprised of nine cirri, which starts behind the cytostome and extends to the posterior end of the cell; the right marginal row, commencing in the mid-body, composed of only five cirri. Consistently six dorsal kineties with stiff cilia 7 μm long (Fig. 5 D). Among them kineties 1, 2, 3 and 5 are almost bipolar. Kinety 4 quite shortened anteriorly, with only four pairs of basal bodies. Kinety 6 shortened posteriorly, extending to mid-body (Figs. 4 B, 5 F). Constantly three fine caudal cirri (Fig. 4 B) located at ends of kineties 1, 2 and 4, consisting of two basal body pairs each. A late divider was recognized (Fig. 5 H – J), from which some traits can be deduced as follows: A new adoral zone of membranelles develops independently in opisthe; five streaks of cirral anlagen (II-VI) plus undulating membranes anlage were formed in both proter and opisthe, respectively. These streaks begin to fragment and (finally) differentiate into new cirri in the following mode: 1: 3: 3: 3: 4: 4 (from left to right), which confirms the presence of 18 frontal-ventral-transverse cirri in interphasic cell of the present form. Two sets of anlagen occur ahead of the parental right marginal row. Dorsal kineties anlagen seem to originate within some old structures. Ecological data. Water temperature 14.8 ºC, pH 8.2, salinity 34.9 ‰, DO 8.1 mg / L. Comparison with some populations. The species was dated to more than 150 years ago, when Cohn first recorded it under the present name. After that, it has been redescribed many times with some details under different names, namely Oxytricha (Actinotricha) saltans, and Oxytricha saltans (Kahl 1932; Berger 1999). Detailed redescriptions with ciliature data of O. saltans were provided by Song et al (1991) and Song & Wilbert (1997). Berger (1999) comprehensively reviewed the research history of Oxytricha saltans. Until 2011, Actinotricha saltans was reactivated by Shao et al. (2011). Only a few live and stained specimens are available for the current form. However, with reference to the bipartite adoral zone with the crown-like apical membranelles, short and parallel undulating membranes, one left and one extremely shortened right marginal row, more than three dorsal kineties, and caudal cirri present, it should be classified into Actinotricha, a monotypic genus with only A. saltans included. Prior to this study, the species had never been recorded in the coastal waters of Japan despite its cosmopolitan distribution. The Japan population resembles previous populations of the species very much in body size and shape, nuclear apparatus, extremely long dorsal cilia as well as the arrangement of cirri (three frontal, one buccal, four frontoventral, three postoral, two pretransverse ventral and five transverse cirri) on ventral size, which was distinctly illustrated in Rees (1884) (redrawn as Fig. 87 e and g in Berger, 1999) and its identification is unquestionable. In terms of ciliature, only Qingdao populations can be used for comparison (Song et al. 1991; Song & Wilbert 1997). It is curious that two Qingdao populations have almost identical morphometric data. But the present form corresponds well in most diagnostic features (see above), except minute difference in the number of frontoventral cirri (4 vs. 3 as described). The presence of four frontoventral cirri in the Japan isolate can be confirmed by a late divider (see above). By contrast, the record of three frontoventral cirri was not substantiated by any micrograph in Qingdao population of Song et al. (1991). Considering all species of genus Oxytricha, in which this species was placed for a long time, constantly have four frontoventral cirri, misinterpretation cannot be excluded for the 1991 population. Of course, another possibility occurs, i. e. the form reported in 1991 did possess the slight reduction of frontoventral cirri, which can be attributed to the resorption of kinetosomes during pattern formation. Song & Wilbert (1997) also described another Qingdao population with invariable seven frontal cirri (including buccal and frontoventral cirri; see Fig. 5 b and d in the original publication). However, the line illustrations are inconsistent with the micrograph of one stained specimen provided in the same paper (the original Fig. 20, unfortunately, not cited), which show the presence of four frontoventral cirri. Therefore, misinterpretation existed for the description of 1997 population. As regards the details about dorsal ciliature, the location and shortness of dorsal kineties 4 and 6 recognized in current study may infer that this species shows dorsal kinety fragmentation and dorsomarginal kinety, a feature also illustrated by Song et al. (1991) and Song & Wilbert (1997) though these authors did not mention them clearly.	en	Hu, Yue, Suzuki, Toshikazu, Hu, Xiao-Zhong (2025): Taxonomic study on marine ciliates from Japan, with description of a new species, Caryotricha orientalis nov. spec. (Alveolata: Ciliophora). Zootaxa 5584 (2): 243-258, DOI: 10.11646/zootaxa.5584.2.5, URL: https://doi.org/10.11646/zootaxa.5584.2.5
