Trichodina domergui (Wallengren 1897)

(Fig 3F, 4F; Table 6)

Description. (n=9) Medium disc-shaped body having a diameter of 57.5–74.2 (65.85±5.8) µm. The adhesive disc measures 50.5–66.2 (58.35±3.10) µm in diameter, surrounded by a wide border membrane of 3.0–4.0 µm (3.5±0.7) in width. Adhesive disc having a diameter of 5.2–11.4 µm (8.3±4.3) and center of this packed with dotted granules. Diameter of denticular ring is 32.2–45.3 (38.75±9.2) µm consisting of 25–27(26±1.4) numbers of denticles having an 8–10 (9±1) number of radial pins per denticle. Rounded denticle blades relatively small with a well identified ray apophysis. A span of denticle is 12.6–16.0 (14.3±2.4) µm in width and length of denticle is 8.1–10.5 (9.3±1.6) µm. Denticle rays are often wider at their distal ends having a diameter of 2.5–3.5 µm (3.0±0.7). Central part finely developed and well notched into the preceding denticles that extending almost full area of y -1 axis. Length of blade is 5.0–6.5 µm (5.75±1.0). Ray softly curved, with a length of 4.5–6.8 (5.65±1.6) µm.

Taxonomic summary

Host: Carassius auratus auratus (L.)

Locality: Howrah, West Bengal, India (22°35’N, 88°19'E)

Location: Gills

Reference material: Lectotype: In slide no. GF-TD-8/2014, deposited in the collection of the Parasitology Laboratory, Department of Zoology, University of Kalyani, Kalyani, Nadia, West Bengal, India.

Remarks. After considering the photomicrographs of specimens and meristic data from all the populations are illustrated the specimen was simply identified as Trichodina domergui Wallengren (1897). The species T. domerguei has gone through a very complicated history. However, considering the ultimate established data T. domerguei was firstly reported by Wallengren (1897) from the skin of Pungitius pungitius and Gastersteus aculeatus. After that it was reported by different authors, namely, Lom & Stein (1966), Stein (1976), Gaze & Wootten (1998), Xu et al. (1999), Mitra (2002). It has not been reported again up to now in India. Our study puts emphasis on the biodiversity and new host preference of the species. It may be mentioned that, though the dimension of our material is much larger in comparison to others, considering all the morphological characters the specimen described here has been clearly identified as Trichodina domerguei. T. domerguei Wallengren (1897) obtained in the present study is morphometrically compared with Mitra (2002) shown in Table 6.