Family Gruberiidae Shazib et al., 2014
Genus Gruberia Kahl, 1932
Gruberia foissneri spec. nov. (Figures 2-4, Table 1)
Body about 400–800 × 30–50 μm in vivo, slightly contractile, slender with a conspicuously pointed caudal region; macronucleus sausage-shaped; pellicle with rod-shaped, dark-brownish cortical granules and rod-shaped mitochondria (?); 25–37 somatic kineties, several of which are shortened forming a suture near posterior end of body; 76–174 adoral membranelles; paroral membrane fragmented, comprising 29–75 pieces; marine habitat.
A seawater aquarium in the Laboratory of Protozoology (N36°03′45″, E120°19′52″), Qingdao, China. The seawater, stones and sand in the aquarium were collected from Taipingjiao Marine Wetland Park and the Second Beach in Qingdao along with living sea anemones and Ulva lactuca. The water temperature was 24 °C and salinity was 30 ppt.
One protargol-stained slide containing the holotype specimen marked with an ink circle and one slide with paratype specimens are deposited in the Laboratory of Protozoology, Ocean University of China, China, with registration numbers CY201812200101 and CY201812200102. The other two paratype slides are deposited in the Natural History Museum, London, UK, with registration numbers NHMUN 2020.4.6.1 and NHMUN 2020.4.6.2.
We dedicate this new species to Prof. Wilhelm Foissner, Salzburg University, Austria, in recognition of his tremendous contributions to the study of ciliates.
The SSU rDNA gene sequence derived from a single cell isolated from the same population as the holotype is deposited in GenBank (accession number MN783327).
When fully extended, cell about 400–800 × 30–50 μm in vivo, on average about 560 × 40 μm (185–430 × 57–145 μm in protargol-stained specimens) with length to width ratio about 10–18:1. Body flexible and slightly contractile, elliptical in cross-section, anterior end beak-like, posterior part gradually narrows to a pointed end (Figures 2A, 3A–E, I). Macronucleus sausage-shaped with an obvious depression (Figures 2E, 3O–Q, 4H). Micronucleus difficult to recognize either in vivo or in protargol preparations. Contractile vacuole absent. Pellicle thick with rod-shaped, dark-brownish cortical granules (about 1.2 × 0.5 μm in size) embedded in cortex, forming 3–5 irregular lines between adjacent somatic kineties (Figures 2D, F, 3L, M). Mitochondria (?) rod-shaped, about 2.0 × 0.7 μm in size, located underneath cortex forming three or four rows between adjacent ciliary rows (Figures 2F, G, 3N). Cytoplasm opaque at low magnification due to numerous small granules and food vacuoles (Figure 3A–G, J). Locomotion by gliding over substratum.
Twenty-five to 37 somatic kineties composed of dikinetids, only one basal body of each dikinetid bears a cilium (Figures 2H, I, 4G). Somatic cilia 5–7 μm long. About 9–21 shortened somatic kineties, most of which originate from left margin of adoral zone of membranelles or oral cavity, remaining ones interspersed among bipolar kineties (Figures 2H, 4F). Several shortened kineties form a conspicuous suture on ventral side near posterior end of body (Figures 2I, 4I).
Length of oral area relative to body length highly variable, ranging from 25% – 45% (Figures 2B, 3A–E). Adoral zone extends from apical end to main body, oral groove slightly curved to right side, twisted in proximal region making a half-turn as it enters the buccal cavity (Figures 2H, I, 3A–G, 4B, D). About 76–174 adoral membranelles, each composed of one short and two long rows of basal bodies (Figures 2C, H, 4B, D). Cilia of membranelles 11–16 μm long in vivo. Paroral membrane fragmented into about 29-75 pieces and arranged along right side of adoral zone of membranelles, almost all fragments composed of two rows of kinetosomes except several anterior ones which comprise three rows; paroral membrane conspicuous, comprising two portions: fragmented main portion with each fragment composed of 2-5 pairs of kinetosomes; twisted, unfragmented posterior portion (Figures 2C, H, I, 4B–E). Cilia of paroral membrane conspicuous, well-developed, 19–22 μm long in vivo (Figure 3K).
Family Condylostomatidae Kahl in Doflein & Reichenow, 1929
Genus Linostomella Aescht in Foissner et al., 1999
Linostomella vorticella (Ehrenberg, 1833) Aescht in Foissner et al., 1999 (Figures 5–7, Table 1)
1833 Bursaria vorticella n. sp. – Ehrenberg, Abh dt Akad Wiss 237 (original description without illustration) (present work: Table 3) .
1838 Bursaria vorticella Ehrenberg, 1833 – Ehrenberg, Infusionsthierchen 326, 327 [Figure VI] (brief redescription) .
1841 Bursaria vorticella Ehrenberg – Dujardin, Zoophytes 511 (without morphological description, only simple review of Ehrenberg’s works ) .
1870 Condylostoma stagnale – Wrześniowski, Z wiss Zool 20: 487–489 [Figure 20] (redescription of living morphology) (present work: Table 3) .
1922 Condylostoma vorticella (Ehrenberg) Dujardin – Penard, Études Infusoires 201, 202 [Figure 200] (morphological redescription based on living cell) (present work: Table 3) .
1924 Condylostoma vorticella (Ehrenberg, 1833) – Fauré-Fremiet, Bull biol Fr Belg 6: 136–139 [Figure 45] (redescription from life) (present work: Table 3) .
1932 Condylostoma (Bursaria) vorticella (Ehrenberg, 1833) – Kahl, Tierwelt Dtl 25: 457 [Figures 12–14 on page 454, Figure 28 on page 458] (short revision with simple redescription) (present work: Table 3) .
1933 Condylostoma vorticella (Ehrenberg) Dujardin 1841 – Wang & Nie, Contr biol Lab Sci Soc China 10: 45–48 [Figure 36] (redescription of morphology based on living cells) (present work: Table 3) .
1967 Condylostoma vorticella – Tuffrau, Protistologica 3: 381, 382 [Figure 7] (brief redescription) .
1974 Condylostoma vorticella (Ehrenberg) – Pätsch, Arb Inst landw Zool Bienenkd 1: 48, 49 [Figure 38] (brief redescription, including the infraciliature information) (present work: Table 3) .
1978 Linostoma vorticella Ehrenberg – Jankowski, Tezisy Dokl zool Inst Akad Nauk SSSR, Jahr 39 (proposal for the establishment of genus Linostoma ) .
1986 Condylostoma vorticella Ehrenberg,1833 – Dragesco & Dragesco-Kernéis, Faune Tropicale 391–393 [Figures A–D] (simple redescription including infraciliature information) (present work: Table 3) .
1991 Condylostoma vorticella (Ehrenberg, 1838) – Packroff & Wilbert, Arch Protistenkd 140: 132–134 [Figure 7] (detailed morphological redescription from life and protargol-stained individuals) (present work: Table 3) .
1992 Linostoma vorticella (Ehrenberg, 1833) Jankowski, 1978 – Foissner et al., Informationsberichte des Bayer Landesamtes für Wasserwirtschaft 5/92: 390–393 [Figures 1–14] (diagnosis based on previous reports) (present work: Table 3) .
1999 Linostomella vorticella (Ehrenberg, 1833) Aescht nov. nom. nov. comb. – Foissner et al., Informationsberichte des Bayerischen Landesamtes für Wasserwirtschaft 3/99: 655–661 [Figures 1–32] (improved diagnosis provided based on detailed morphological redescription) (present work: Table 3) .
2007 Linostomella vorticella (Ehrenberg, 1838) – Alekperov et al., Protistology 5: 117, 118 [Figure 9, Plate 2D on page 114] (simple redescription) (Present work: Table 3) .
Prior to the current investigation, Linostomella vorticella has been found and reported numerous times, but some details of its morphology remain unknown. Based on both previous and present studies, an improved diagnosis is supplied.
Cell size in vivo about 90–210 × 70–160 μm; body ovoidal or ellipsoidal with anterior end obliquely truncated; macronucleus moniliform with 2–15 nodules; single contractile vacuole posteriorly positioned with a long collecting canal; cortical granules colorless to dark-gray; about 26–51 somatic kineties; buccal cavity conspicuous with numerous oral ribs; 36–51 adoral membranelles; freshwater and marine habitats.
Three voucher slides with protargol-stained specimens are deposited in the Laboratory of Protozoology, Ocean University of China (OUC) with registration numbers: CY2019010501-01, 02, 03.
Morphological description of the Qingdao population
Cell size 135–205 × 70–110 μm in vivo, about 175 × 95 μm on average. Body ovoid in outline with length to width ratio about 1.5–2.0:1 (Figures 5A, H, 6A–C). In general, anterior half wider than posterior half, apical end obliquely truncated, posterior end with a slight depression (Figures 5H, I, 6D, H). Macronucleus moniliform with 5–12 nodules, located in middle portion of body (Figures 5A, E, H, 6N, O, 7A, C). Micronuclei inconspicuous, closely associated with macronuclear nodules (Figure 7G). Contractile vacuole in posterior region, varies in shape during diastolic process, with a collecting canal that extends to anterior region of body (Figures 5A, G, 6K–M). Pellicle soft and thin with numerous spherical, dark-gray cortical granules (about 0.9 μm in diameter) densely distributed between ciliary rows (Figures 5C, 6G). Cytoplasm colorless, invariably filled with numerous globular particles and food vacuoles filled with algae (Figures 5A, 6J, K–N). Locomotion by swimming while rotating about main body axis.
Thirty-seven to 51 somatic kineties composed of dikinetids, only one basal body of each dikinetid bears a cilium (Figures 5D, E, 6F, 7H). Somatic cilia 9–12 μm long. About 11–18 ventral kineties are shortened since they originate below buccal cavity; all dorsal kineties extend along complete length of cell (Figures 5D, E, 7A, B, F).
Buccal cavity prominent, length about 35% – 60% of body length, with numerous oral ribs (Figures 5H, 6A–C, 7C, D). Oval glabrous protuberance with fiber-like stripes visible in slightly squashed specimens (Figures 5B, 6I, M). Adoral zone of membranelles prominent, composed of 36–51 membranelles, most of which consist of two rows of basal bodies of equal length; several adoral membranelles in middle portion consist of three rows of basal bodies, third row with only two or three basal bodies (Figures 5D, F, 7E). Cilia of adoral membranelles 20–30 μm long in vivo. Paroral membrane conspicuous, curved and lies along right margin of buccal cavity, anterior portion curves toward the left side of buccal cavity, posterior portion located near distal end of adoral zone (Figures 6A, E, 7B–D).