Tripartiella orthodens Basson & Van As , 1987

Tang, Fahui, Zhao, Yuanjun & Liu, Chunning, 2013, First records of three Tripartiella species (Ciliophora, Oligohymenophora, Peritrichida) from freshwater fishes along Yangtze River in China, Zootaxa 3681 (2), pp. 169-174 : 172

Tripartiella orthodens Basson & Van As, 1987

Host: Pelteobagrus nitidus

Locality: Shapingba, Chongqing

Site: Gills

Date of sampling: February, 2009

Description ( Figs. 3, 4 , 8 ). The following morphological description were based on 18 specimens measured (n = 18). Small to medium freshwater Tripartiella with a disc-shaped body, diameter 20.0–30.0 (25 ± 2.5); adhesive disc 16.0–26.0 (21 ± 2.3); width of border membrane 1.5–2.0 (1.8 ± 0.2); diameter of denticle ring 9.0–16.0 (11 ± 1.7); number of denticles 24 - 27; number of radial pins per denticle usually 4–5; span of denticle 5.0–7.0 (6.0 ± 0.7); length of denticle 2.0–3.0 (2.3 ± 0.4); blade length 3.0–4.0 (3.4 ± 0.4), generally narrow with anterior and posterior margins parallel. Distal margin rounded, nearly parallel with border membrane, and higher than tangent point; anterior and posterior surfaces straight and smooth and almost parallel with each other with the anterior surface just touching the Y +1 axis; blade apophysis and posterior projection present but not very distinct. Central part barely developed with a round point fitting tightly into preceding denticle and far away from the Y-1 axis. Shapes of the central part above and below the X-axis almost similar and 1.0–3.0 (1.5 ± 0.4) in width. Ray connection hardly conspicuous and hardly distinguishable from the ray. Ray short, straight, erect and nearly attached to the Y axis with a blunt point of ray; ray apophysis absent and length of ray was 1.0–1.5 (1.1 ± 0.2); ratio between denticle above and below X axis more than two. Macronucleus C-shaped, external diameter 15.0–22.5 (17.8 ± 1.1) and internal diameter 12.5–17.5 (15.6 ± 1.3). Micronucleus elliptical, 1.0–2.5 (1.7 ± 0.2) in length and 0.5–1.5 (1.2 ± 0.3) in width, situated in + Y position. Adoral ciliary spiral turns about 230° - 270° around peristomial disc.

Remarks. Tripartiella orthodens was first found and described from Tilapia rendalli swierstrai by Basson and Van As (1987) in the Sabie River of the Komati River system, South Africa. Tripartiella orthodens is characterized by the erect ray and the morphology and morphometric data of the present population from gills of Pelteobagrus nitidus fall well within the range of the original description with the only exception the smaller body size (20.0– 30.0µm in present population vs. 27.6–36.5µm in original population). This species has not been reported since its first description from Tilapia rendalli swierstrai by Basson and Van As in 1987, and thus this report is the first record of Tripartiella orthodens in Asia.

Figures

FIGURES 1 – 6. Photomicrographs of silver impregnated adhesive disc of Tripartiella species. 1 - 2. Tripartiella obtusa Ergens & Lom, 1970; 3 - 4. Tripartiella orthodens Basson & Van As, 1987; 5 - 6. Tripartiella macrosoma Basson & Van As, 1987. (Scale bars = 20 µm).

FIGURES 7 – 9. Diagramatic drawings of the denticles of three Tripartiella species. 7. Tripartiella obtusa Ergens & Lom, 1970; 8. Tripartiella orthodens Basson & Van As, 1987; 9 Tripartiella macrosoma Basson & Van As, 1987.