Platina marina Jiang & Wang & Liao & Al-Farraj & Warren & Hu 2024, gen. nov., sp. nov.
Creators: name: Jiang, Limin
name: Wang, Congcong
name: Liao, Lijian
name: Al-Farraj, Saleh A.
name: Warren, Alan
name: Hu, Xiaozhong
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Chromista
Ciliophora
Prostomatea
Prostomatida
Apsiktratidae
Platina
Platina marina

description: Platina marina gen. nov., sp. nov.
(Figs 2, 3; Table 1)
Zoobank registration: urn:lsid:zoobank.org:act: 3EAF307E-73C6-4AF9-BD92-67ADE3BB3193
Diagnosis: Body size ~40–85 μm × ~15–25 μm in vivo; dorsoventrally flattened ~2:1; single globular to ellipsoidal macronucleus and single ellipsoidal micronucleus; circumoral kinety with a ventral gap, composed of 10–12 dikinetids; ~45 longitudinal perioral kineties forming six rings, i.e. four anterior rings arranged as two pairs and two well-separated posterior rings; 9–11 longitudinal somatic kineties forming 15–21 transverse rows that are confined to the ventral side except for the second transverse row, which surrounds the body.
Type locality: Intertidal zone of the Yellow Sea coast near Zhanqiao Pier, Qingdao (36°04ʹ03″N, 120°19ʹ35″E), Shandong Province, China. The salinity was 31‰ and the water temperature 10°C.
Type specimens: A protargol slide containing the holotype specimen (registration number:JLM2021113001-1; Fig.2B, C) was deposited in the Laboratory of Protozoology, Ocean University of China. A second protargol slide (registration number: JLM2021113001-2) containing paratype specimens was deposited in the Marine Biological Museum, Chinese Academy of Sciences, Qingdao.
Etymology: The species-group name marina (Latin adjective; living in the sea) alludes to the marine habitat where the species was found.
Description: Cell size in vivo ~40–85 μm × ~15–25 μm, on average 50 μm × 15 μm, with a length-to-width ratio of 2–4:1 (Figs 2A, 3A). Main part of body flattened dorsoventrally ~2:1 and progressively more flattened from anterior end to posterior end (Figs 2A, F, 3A–I); transverse bulge located in anterior quarter of body on dorsal side where one row of somatic cilia is located (Figs 2F, 3H, I). Anterior end of body, with conspicuous apical plate; posterior half of body distinctly narrowed, with a broadly pointed caudal end (Figs 2A, 3A). Individuals vary widely in shape, usually spindle shaped, with posterior region curved back towards ventral side (Fig. 3A, I). Outline not symmetrical, some individuals with a head that is turned to one side; body flexible but not contractile; body surface uneven (Figs 2A, 3A–I). Oral basket and nematodesmata absent; cytostome apically located but not conspicuous; perioral cilia densely arranged (Figs 2A, 3K). Silverline system easily recognized in vivo; ventral argyrome consisting of regular rectangles, one between adjacent kineties; dorsal argyrome consisting of polygons of different sizes; perioral argyrome formed by slender rectangles that encircle head (Figs 2G, H, 3J–L). Ectoplasm forms conspicuous transparent alveolar layer with protrusions all around the cell; three shapes of alveolar layer correspond to pattern of silverline system, i.e. regular rectangles, polygons and slender rectangles on ventral side, dorsal side and around oral area, respectively (Figs 2A, 3A–L). Cytoplasm colourless but partly opaque at low magnifications owing to presence of refractive inclusions and small granules (Fig. 3C, E). Single macronucleus, globular to ellipsoidal, ~7–10 μm × ~5–8 μm after protargol staining, centrally located, with numerous spherical nucleoli ~1 μm wide (Figs 2C, 3M, N). Single ellipsoidal micronucleus, adjacent to macronucleus, ~2 μm × ~3 μm (Fig. 3N). No contractile vacuole or cortical granules observed. Locomotion by swimming moderately fast in upper layer of water with an irregular trajectory.
Most somatic cilia ~9–10 μm long; perioral cilia slightly longer, ~10–11 μm long; single caudal cilium, ~25 μm long (Figs 2A, 3B). Perioral kineties consisting of 43–48 longitudinal rows of kinetids, forming six rings that encircle the anterior region of the body, considerably more densely ciliated than other somatic kineties; four anterior rings arranged as two pairs, two posterior rings well separated (Figs 2B–E, I, 3O–R). Other somatic kineties monokinetid, composed of 9–11 longitudinal rows of monokinetids (here referred to as longitudinal kineties), kinetids of which form 15–21 transverse rows that are confined to ventral side, except second transverse row, which surrounds the body (Figs 2B–E, I, 3Q, R). Circumoral kinety consists of 10–12 pairs of kinetids, with a conspicuous gap on the ventral side, thus not forming a circle (Figs 2B–E, I, 3O, R).
description: Published as part of Jiang, Limin, Wang, Congcong, Liao, Lijian, Al-Farraj, Saleh A., Warren, Alan & Hu, Xiaozhong, 2024, Re-evaluation of the systematic position of the order Prostomatida (Protista: Ciliophora), with the establishment of two new genera and two new species, pp. 849-864 in Zoological Journal of the Linnean Society 200 (4) on pages 851-853, DOI: 10.1093/zoolinnean/zlad116, http://zenodo.org/record/11241025