Trochilioides tenuis (Deroux, 1976) Chen et al. 2011

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 : 27-30

Trochilioides tenuis (Deroux, 1976) Chen et al. 2011 ( Fig. 2 ; Table 1)

According to Article 13.3.3 of ICZN (1999), Trochilioides Kahl, 1931 is a nomen nudum, so Chen et al. (2011) re-established the genus by fixing T. recta as type species. Trochilioides tenuis was originally report- ed by Deroux (1976c), based only on its infraciliature. So far no re-description has been attempted, we here redescribe it based on a Qingdao population.

Improved diagnosis: Small Trochilioides , 30–40 × 20–35 μm in vivo, body elliptical in outline; consistently three right kineties, four left kineties and seven postoral kineties; single contractile vacuole located at anterior of right side; marine habitat.

Description of Qingdao population: Cell size about 30–40 × 20–35 μm in vivo; body usually elliptical in outline with anterior end bluntly rounded and posterior end somewhat tapered ( Fig. 2A, H, I ). Ventral side flat and dorsal side humped with several longitudinal stripes after protargol impregnation ( Fig. 2D, J, P ). Usually, rice-like pellicular granules irregularly distributed on dorsal side ( Fig. 2K ). Cytostome prominent, oval shaped, ventrally positioned in anterior 1/5 of cell ( Fig. 1H ); but nematodesmal rods not detected. Cytoplasm colourless, containing numerous small, greasily shinning globules (2–3 μm across), and food vacuoles (4–8 μm across), which render cells slightly greyish ( Fig. 2L, N ). Single contractile vacuole, about 5 μm in diameter, located at anterior 1/3 of right side. Single oval macronucleus centrally positioned, about 11 × 6 μm in vivo ( Fig. 2A, L ). Podite leaf shaped and 5 μm long, subcaudally located ( Fig. 2A, H ). Cilia 7 μm long. Movement by gliding on the substrate.

Infraciliature as shown in Fig. 2E, F, G, M, O, P . Consistently, three right kineties, seven postoral kineties and four left kineties surrounding the cytostome. Two right-most kineties almost equal in length, extending anteriorly to anterior margin ( Fig. 2G, O ). Posterior ends of right kineties terminating at the same level and a fragment, comprising three or four basal bodies, located on the left of them. Left and postoral kineties very short, the posterior ends of which are progressively shortened from right to left ( Fig. 2M ). Equatorial fragment composed of 0–8 basal bodies, and terminal fragment consisting of 2–4 ones ( Fig. 2G, O ). The oral ciliature composed of three dikinetid fragments: two circumoral kineties (Co) arranged in parallel, equal in length; and one preoral kinety, relatively long, obliquely arranged in front of Co ( Fig. 2G, M, O ). During cell division, the oral primordium of opisthe generated from three sections of postoral kineties ( Fig. 2E, F ).

Remarks: The infraciliature of the Qingdao population corresponds with the original description very well ( Fig. 2B, C ; Deroux 1976c), although our isolate is a little larger in size (23–33 μm long vs. 15–25 μm long after protargol impregnation). Considering that the size usually changes in different populations, we believe the two to be conspecific.

Figures

Fig. 2A–P. Trochilioides tenuis from life (A, D, H–L, N) and after protargol impregnation (B, C, E–G, M, O, P). A – ventral side of a representative individual; B, C – from Deroux (1976c); D – dorsal view in vivo; E, F – individuals in division; G – to show infraciliature; H, I – ventral views, arrow (H) refers to cytostome; J – dorsal view, arrowhead points to contractile vacuole; K – to show pellicle granules in dorsal side; L – details of cytoplasm, arrowhead marks contractile vacuole and arrow indicates macronucleus; M, O – infraciliature of different individuals, arrow (O) refers to equatorial fragment; N – ventral view; P – dorsal view. Co – circumoral kineties; EF – equatorial fragment; FvK – frontoventral kineties; LK – left kineties; Pr – preoral kinety; TF – terminal fragment. Scale bars: 20 µm.

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.