Tripartiella obtusa ( Ergens & Lom 1970 )

Saha, Mandira & Bandyopadhyay, P. K., 2016, First report of some known Trichodinella epizootica Šramek-Hušek, 1953, and Tripartiella Lom, 1959 from the cultured Oranda Gold Fish (Carassius auratus auratus) in India, Zootaxa 4184 (1), pp. 130-140 : 137

Tripartiella obtusa ( Ergens & Lom 1970)

( Fig. 3 D, 3E, 3F; Table 3)

Description (Number of specimens measured—35). Very small size disc shaped ciliophoran having a diameter of 12.0–24.5 (18.25±8.8) with a concave adhesive disc about 10.5–19.2 (14.85±6.1) diameter, is surrounded by a finely striated border membrane width of 1.0–2.0 (1.5±0.7) diameter. Central area of the adhesive disc is uniformly dark and measuring about 3.1–6.5 (4.8±2.4). The blade is elongated and slanted in a backward direction. Denticular ring having a diameter of 7.1–9.7 (8.4±1.8). The distal margin is rounded to a curved tangent point which forms a line with y - 1 axis and situated below the distal margin shown in Fig. 3 F. The anterior projection resembles a rounded triangle, forms together with a ‘‘V’’ shaped blade pointed anticlockwise. The part of blade adjoining this projection is stalk like and length of blade is 3.3–4.0 (3.65±0.4). Due to bilateral convexity the shape of the blade somehow appears club-shaped. The posterior projection is poorly developed. The anterior projection fits well into the notch of the preceding denticle and it is connected to the central part by a well developed, but straight section. The central part is delicate and bluntly rounded in shape and having a width of 0.5–1.5(1.0±0.7). The ray is stout, straight directed anteriorly and terminates in a rounded point having a length 1.0–1.9 (1.45±0.6). This ciliophoran having a number of radial pins per denticle 3–5 (4.0±1.4), number of denticles 17–25 (18.5±2.1), dimensions of denticle, length 2.0–3.1(2.55±0.7), span 5.5–8.0 (6.75±1.7). No significant variation in shape and structure of the denticles of the specimen has been found in the present studies with the findings of previous authors.

Taxonomic summary:

Host: Carassius auratus auratus (L.)

Locality : Haringhata, Nadia, West Bengal, India (22°53’N – 24°11’N / 88°09’E – 88°48’E)

Location: Gills

Reference material. Lecotype: In slide no. GF-TPO-12/2014, deposited in the collection of the Parasitology Laboratory, Department of Zoology, University of Kalyani, Kalyani, Nadia, West Bengal, India.

Remarks. On analyzing the morphmetric and quantitative data of the present specimen, it was readily identified as Tripartiella obtusa Ergens & Lom (1970) . Ergens & Lom (1970) Mitra (2002) found this ciliophoran regularly, but exclusively on the gills of some edible fish but this is first time that, aquarium fish Carassius auratus auratus (L.) act as host for the parasites which supplements a new ideas on its biodiversity. This ciliophoran is quite similar to the earlier described ones. However, the dimensions of the present ciliophoran are somewhat smaller than those of Ergens & Lom (1970). This variation might be due to the difference in the host fishes from where the trichodinid ciliophoran were collected.

Figures

FIGURE 3. Microphotographs of Tripartiella species recovered from Carassius auratus auratus (L.). (A & B) Photomicrographs of silver nitrate impregnated adhesive discs of T. copiosa (Lom 1959) with its schematic diagram present in (C). (D & E) Showing the silver nitrate impregnated adhesive discs of T. obtusa (Ergens & Lom 1970) with its schematic diagram present in (F). Scale bars 10 µm.