Orthotrochilia sinica, Pan & Ma & Hu & Al-Rasheid & Al-Farraj, 2013

Pan, Hongbo, Ma, Honggang, Hu, Xiaozhong, Al-Rasheid, Khaled A. S. & Al-Farraj, Saleh A., 2013, Taxonomic Studies on Three Marine Ciliates from China, Including a New Species (Ciliophora, Cyrtophorida), Acta Protozoologica 52 (1), pp. 25-33 : 26-27

Orthotrochilia sinica spec. nov. ( Fig. 1 ; Table 1)

Diagnosis: Marine Orthotrochilia with slender elliptical body shape, about 50–60 × 20–25 μm in vivo; 18–21 somatic kineties, two frontoventral kineties; the length of left perioral kinety treble the length of right one; two contractile vacuoles ventrally located on right side; 25–32 nematodesmal rods.

Slides deposition: A protargol slide (registration number: PHB08110301-1) with the holotype specimen and one protargol slide (registration number: PHB08110301-2) with paratype specimens are deposited in the Laboratory of Protozoology , OUC, China. Relevant specimens are marked by black ink circles on the cover-slip .

Type location: Coastal waters off Xiaogang Port in Qingdao (36°18′N, 120°43′E), China .

Description: Cell size about 50–60 × 20–25 μm in vivo. Body elliptical in outline with anterior end bluntly rounded and posterior tapered ( Fig. 1A, F, I, J ). Dorsal side vaulted with a longitudinal furrow in middle, while ventral side flattened ( Fig. 1B, C, H, L ). Cytostome sub-apically located, about 9 μm in width, and surrounded by 25–32 nematodesmal rods ( Fig. 1F, D, M ). Cytoplasm colourless, containing numerous small, greasily shining granules. Two contractile vacuoles, 4–5 μm in diameter, positioned in anterior and posterior 1/4 of body length, near right margin; contracting interval about 16 seconds ( Fig. 1C, G ). Podite, about 10 μm long, subcaudally positioned ( Fig. 1I ). Single macronucleus ellipsoid, about 25 × 11 μm in vivo, centrally located ( Fig. 1G ). Cilia about 10 μm long. Movement by slowly gliding on the substrate.

Infraciliature as shown in Fig. 1D, E, K, M . In total, 18–21 somatic kineties, the two right-most of which are almost equal in length, with both extending anteriorly and bending to the left side; the five right-most kineties terminating posteriorly at the same level, while others are progressively shorten from right to left ( Fig. 1D, K, M ). Equatorial fragment composed of 3–12 basal bodies, and terminal fragment consisting of 6–11 ones ( Fig. 1D, E ). About 4–6 kinetosome-like dots present near the base of the podite ( Fig. 1D ). Oral ciliature typical of the genus Orthotrochilia : two perioral kineties composed of dikinetids and distinctly separated; the left kinety triple the length of the right one ( Fig. 1D, M ).

Remarks and comparison: The genus Orthotrochilia was first established by Deroux (1976c). Because no type species was fixed, however, it was a nomen nudum according to Article 13.3.3 of ICZN (1999). Song (2003) re-studied Orthotrochilia pilula and re-established the genus by fixing O. pilula as the type species. To date, only two species are included in this genus, i.e. Orthotrochilia pilula (Deroux, 1976) Song, 2003 and O. agamaleivi (Deroux, 1976) Song, 2003 .

In terms of size and cell shape, the new species resembles Orthotrochilia agamaleivi . It can be distinguished, however, in that it has more somatic kineties (18–21 vs. 12–18), fewer nematodesmal rods (25–32 vs. ca. 40) and a longer left perioral kinety (triple the length of the right perioral kinety vs. nearly equal in length; Deroux 1976c). Meanwhile, compared to O. pilula , O. sinica is larger in size (50–60 × 20–25 μm vs. 20–30 × 15–20 μm), and possesses more somatic kineties (18–21 vs. 9) and nematodesmal rods (25–32 vs. ca. 6; Song 2003).

Figures

Fig. 1A–M. Orthotrochilia sinica spec. nov. from life (A–C, F–J, L) and after protargol impregnation (D, E, K, M). A – ventral view of a representative individual; B, L – lateral view; C – to show contractile vacuoles (arrowheads) and the furrow in dorsal side; D, E – infraciliature of ventral (D) and dorsal (E) side; F, G – ventral view, arrow (F) indicates cytostome and arrowheads (G) mark contractile vacuoles; H – dorsal view; I, J – ventral view of different individuals, arrowhead (I) indicates the podite; K – posterior portion; M – infraciliature. EF – equatorial fragment, Ma – macronucleus, PK – perioral kineties, TF – terminal fragment. Scale bars: 30 μm.