Trichodina uniforma Van As & Basson, 1989

Tang, Fahui, Zhao, Yuanjun & Tao, Yanfei, 2007, Trichodinids (Ciliophora: Peritrichida) parasitic on gills of freshwater fishes, Carassius auratus and Aristichthys nobilis from China, with the description of Trichodina subtilihamata sp. nov., Zootaxa 1582 (1), pp. 39-48 : 42

Trichodina uniforma Van As & Basson, 1989

( Figs. 1C , 3C )

Host: Carassius auratus .

Location: Gills.

Prevalence: Out of nine fishes examined, one was infected (11%).

Locality: Chongqing, China (29º5' N, 106º5' E) .

Date of sampling: February, 2003.

Description. Large-size, disc-like in shape when viewed laterally, body diameter 61.5–69.0µm (63.9 ± 3). Diameter of adhesive disc 50.0– 56.5µm (52.3 ± 2.3). Border membrane 6.0–7.0µm (6.4 ± 0.4) in width. Diameter of denticulated ring 33.0–37.0µm (34.5 ± 1.5). Centre of disc clear and without any guanules. Number of denticles 28–30 (n = 11) and number of radial pins per denticle 9–11 (n = 11). Span of denticle 16.5– 20.0µm (17.9 ± 1.2). Length of denticle 6.5 - 8.5µm (7.4 ± 0.7). Blade broad, filling almost entire space between Y axes, length 6.5–7.0µm (6.7 ± 0.3); distal blade surface straight and smooth, surface parallel to border membrane; anterior and posterior surface nearly straight and parallel to each other, mostly anterior surface extending just beyond Y+1 axis; tangent point of blade slightly higher than distal surface of blade in most specimens, and rarely on same level as distal surface; posterior margin forming extended curve, with lowest point lower than apex. Blade apophysis and posterior projection not present. Central part relatively thin but with rounded point fitting tightly in the proceding denticle and extending more than half way to Y-1 axis. Width of central part 2.0– 3.5µm (2.7 ± 0.4). Ray well developed, of equal thickness and bending slightly inanterior direction. Point of ray sharp, touching or extending past Y+1 axis, length 7.5–9.5µm (8.5 ± 0.9). Ray apophysis present and small, but inconspicuous in some specimens. Ratio of denticle above to below X axis less than one. Macronucleus horseshoe-shaped, external diameter about 58; distance between terminations of macronucleus about 14; micronucleus oval, situated in +Y position. Adoral ciliary spiral turns about 390º around peristomial disc.

Remarks. This species was found on the gills of Carassius auratus , accompanied by Trichodinella epizootica (Raabe, 1950) Sramek-Husek, 1953 and Trichodina reticulata Hirschmann & Partsch, 1955 , but with a lower intensity of infestation than Trichodinella epizootica . The morphometric data and denticle shape of our population are consistent with the original description of T. uniforma ( Van As & Basson, 1989) . However, our population shows some difference from the original population, perhaps because of the geographical distributions. In our population, the central part is more delicate than the original. Furthermore, in the original description of T. uniforma , the ray apophysis is more conspicuous than ours. Regardless of differences in blade morphology, we consider these differences to be within the range of variability for T. uniforma . This species had not been reported since its first description from Carassius auratus at Falls Fish Farm (25º25'S, 30º35'E) in the Komati River system, Eastern Transvaal, South Africa by Van As & Basson in 1989, and thus this report is the first record of T. uniforma in Asia.

Figures

FIGURE 1. Photomicrographs of silver impregnated specimens of Trichodina spp. A–B. Trichodina subtilihamata sp. nov; C: Trichodina uniforma Van As & Basson, 1989; D: Trichodina nigra Lom, 1960. Scale bar = 20m.

FIGURE 3. Diagrammatic drawing of the denticles of Trichodina spp. A–B. Trichodina subtilihamata sp. nov.; C: Trichodina uniforma Van As & Basson, 1989; D: Trichodina nigra Lom, 1960; E–F: Trichodina kazubski Van As & Basson, 1989; G–H: Trichodina mutabilis Kazubski & Migala, 1968.