Thuricola obconica, Lu & Ji & Sheng & Song & Hu & Chen & Al-Rasheid, 2018
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publication ID |
https://doi.org/ 10.4467/16890027AP.18.011.8985 |
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persistent identifier |
https://treatment.plazi.org/id/B96387FB-FFB9-E01C-FF20-FB0714E07156 |
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treatment provided by |
Felipe |
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Thuricola obconica |
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Thuricola obconica Kahl, 1933 View in CoL ( Figs 2A–R View Fig , 3A–S View Fig , Table 1)
1933 Thuricola obconica n. sp. –Kahl, Tierwelt Nord Ostsee., p. 135, Fig. 24: 7.
1935 Thuricola obconica Kahl, 1933 View in CoL –Kahl, Tierwelt Dtl., p. 786, Fig. 145: 7–8.
1952 Thuricola obconica Kahl, 1933 View in CoL –Bock, Kieler Meeresforsch., 8: p. 227, Fig. 2a, b View Fig .
1952 Thuricola kamptostoma View in CoL n. sp. –Bock, Kieler Meeresforsch., 8: p. 227–228, Fig. 3 View Fig .
1980 Thuricola obconica Kahl, 1933 View in CoL –Trueba, Beaufortia, 30: p. 134, Fig. 5g View Fig .
Although T. obconica View in CoL had been described several times, morphological data on the species remain somewhat deficient. Furthermore, the inconsistencies in the descriptions provided in the literature suggest that the previous studies may contain some misidentifications. A detailed redescription based on modern criteria is therefore imperative.
Emended diagnosis: Lorica colourless and ca. 120–210 μm long, cross-section sub-circular, nearly symmetrical on wider side and asymmetrical on narrower side, curved before valve base, posterior portion tapering to a base with two annular bulges, base expanded. Valve in upper third of lorica. One or two zooids, 195–310 × 15–32 μm in vivo. Stalk about 10 μm long. Peristomial lip single-layered and strongly everted. Contractile vacuole dorsally located. Row 1 of infundibular polykinety 3 about twice as long as the other two. About 105–120 transverse silverlines from peristome to trochal band, 95–110 from trochal band to scopula.
Voucher slides: Six voucher slides with protargol stained specimens (registration number LU20170220- 01-01-06) have been deposited in the Laboratory of Protozoology, Ocean University of China.
Description: Cell size about 195–310 × 15–25 μm (n = 9) in vivo. Generally, one or two zooids within a lorica. When two zooids co-exist, they are abreast of each other but anisometric. Solitary zooid relatively smaller. When extended, zooid is slender and trumpet-shaped, expanded gradually anteriad, widest at oral opening ( Figs 2A–D View Fig , 3A–E View Fig ). Zooid highly flexible and contractile. When stimulated, zooid contracts into lorica and becomes ellipsoid or broadly conical in outline ( Fig. 3F–H View Fig ). Peristomial lip thin and single-layered, about 38–48 μm in diameter when fully expanded. Peristomial disc strongly elevated ( Figs 2A, B View Fig , 3A–E, I View Fig ). Pellicle covered with shallow, narrowly spaced traverse striations ( Figs 2J View Fig , 3N View Fig ). Striations hardly recognizable at low magnifications, but clearly visible above 400 × magnification. Trochal band, a conspicuously bulged ring-like structure, located near mid-body ( Figs 2J View Fig , 3N View Fig ). About 105–120 striations from peristome to trochal band and 95–110 striations from trochal band to scopula (counted from live materials; n = 4).
Cytoplasm colourless and full of granules usually less than 2 μm in diameter. Single contractile vacuole located at the same level as peristomial lip and on the dorsal wall of infundibulum ( Figs 2A, B View Fig , 3I View Fig ). Food vacuoles about 5–10 μm across, usually positioned in the middle portion of body ( Figs 2A, B View Fig , 3A–H View Fig ). Some- times, several large irregular-shaped refractive granules scattered in cytoplasm.
Macronucleus rather hyaline and thus difficult to recognize in vivo, vermiform in shape, longitudinally oriented, nearly passing through the whole body with a transverse curvature at oral end, attenuating gradually from top to bottom ( Figs 2C View Fig , 3O–Q View Fig ). Due to significant shrinkage in the fixation process, macronucleus in protargol stained specimens highly twisted ( Figs 2L View Fig , 3O–Q View Fig ).
Zooid attached to lorica via an inner stalk, around 10 μm long ( Figs 2A–D View Fig , 3A–H View Fig ). Stalk has longitudinal striations only visible at high magnifications. Both ends of stalk expanded ( Figs 2I View Fig , 3K View Fig ).
Lorica of Thuricola obconica transparent and colourless, about 155–210 μm long, conical in aboral third and with a laterally bent anterior portion. In lateral view from the narrow side, lorica about 40–50 μm (average 46.5 μm, n = 10) wide, widest about two-thirds of its length from aperture to base ( Figs 2A–C, F–H View Fig , 3A–H View Fig ). Lorica usually bent differently at anterior third ( Figs 2A–H View Fig , 3A, D, E, F, H View Fig ). In lateral view from the wide side, lorica slightly wider (47 μm, n = 1), and almost rectangular in outline at upper two thirds ( Figs 2D View Fig , 3C View Fig ). At posterior third, lorica narrowed with two inconspicuous annular bulges ( Figs 2A–H View Fig , 3A–H, K, L View Fig ). Bottom expanded ( Figs 2I View Fig , 3K View Fig , arrow). One valve inserted at anterior third ( Figs 2A–H View Fig , 3A–H, M View Fig ). Its base curved and thus conducive to closing and opening ( Figs 2A–C, F–H View Fig , 3A, B, D–H, M View Fig ). Valve connected to a junctional membrane (JM). JM thin and hyaline, making it hard to confirm fine three-dimensional structure under light microscope. Viewed from the narrower side of lorica, JM presents two short “V” shaped lines above inner stalk and two short longitudinal lines around stalk ( Figs 2A– C, F–H View Fig , 3K View Fig , arrow), whereas it shows two long lines that nearly symmetrical with smooth curves above inner stalk and two short longitudinal lines around stalk between valve and lorica floor when lorica rotated by 90° ( Figs 2E View Fig , 3C, L View Fig , arrowheads).
Oral cilia about 18 μm long, positioned around peristomial disc and lip. Oral apparatus composed of haplokinety and polykinety; both circling about 1.5 turns around peristomial disc before entering infundibulum where they make a further turn. Infundibular part of polykinety (P1) accompanied by other two kineties (P2–3), composed of three parallel rows of kinetosomes each. Three rows of P1 equal in length and extending to cytostome ( Figs 2M View Fig , 3R, S View Fig ). P2 interposed between P1 and P3. Arrangement of three kinetosomal rows of P2 somewhat staggered: row 1 extends abstomally and considerably longer than rows 2 and 3, terminating adstomally ahead of row 2 and 3 at the last curvature of P1; row 2 runs parallel with row 1 and separate from row 3 at abstomal half ( Figs 2M View Fig , 3R View Fig ). Row 1 of P3 originates from the middle of P2, while rows 2 and 3 become shortened abstomally. Adstomally P3 converges with P1, both of which terminate at the end of the infundibulum ( Figs 2M View Fig , 3R, S View Fig ). Epistomial membrane 1 located near the entrance of infundibulum ( Figs 2M View Fig , 3R View Fig ). Epistomial membrane 2 short, located ahead of the beginning of polykinety and haplokinety ( Figs 2M View Fig , 3R View Fig ). Trochal band encircling body equatorially. Germinal kinety parallel to haplokinety, ending at last curve of haplokinety ( Figs 2M View Fig , 3R View Fig ).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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Thuricola obconica
| Lu, Borong, Ji, Daode, Sheng, Yalan, Song, Weibo, Hu, Xiaozhong, Chen, Xiangrui & Al-Rasheid, Khaled A. S. 2018 |
Thuricola kamptostoma
| Lu & Ji & Sheng & Song & Hu & Chen & Al-Rasheid 2018 |
Thuricola obconica
| Kahl 1933 |
Thuricola obconica
| Kahl 1933 |
Thuricola obconica
| Kahl 1933 |
T. obconica
| Kahl 1933 |