Trichodina acuta Lom, 1961

Yuryshynets, Volodymyr, Ondračková, Markéta, Kvach, Yuriy & Masson, Gérard, 2019, Trichodinid Ectoparasites (Ciliophora: Peritrichia) of Non-native Pumpkinseed (Lepomis gibbosus) in Europe, Acta Protozoologica 58 (2), pp. 69-79 : 70-71

Trichodina acuta Lom, 1961 ( Figs.1 A, B )

Locality. Helpůn borrow pit, Danube river drainage, Czech Republic

Comparative description: Large trichodinid with flattened, disc-shaped body, 53.0–64.5 (58.1, 5) in diameter. Adhesive disc concave, 43.7–54.7 (48.1, 5) in diameter; surrounded by finely striated border membrane 4.6–6.1 (5.0, 5) wide. Diameter of denticle ring 25.8–32.0 (28.7, 5). Centre of adhesive disc bears a clear or not so intensively impregnated area 8.8–11.7 (9.9, 5) in diameter, containing some darker spots. Number of denticles 18–22 (20, 5). Length of denticle 8.2–9.9 (8.9); span 11.1–14.8 (13.1); length of ray 5.6–7.7 (6.3); width of central part 2.7–3.2 (2.9); length of blade 4.3– 5.6 (5.0). The blade is broad, filling large portion of sector between Y and Y+1 axes. Tangent point sharp, with distal margin slightly higher or at same level as tangent point. Posterior margin indentation forms small semi-lunar arch with Y axis, with deepest point slightly lower than blade apex. Blade apophysis developed and angular, coinciding with posterior projection in previous denticle. The distinction between the central part, ray and blade is pronounced. Central part robust and widely triangular with bluntly rounded tip which extends more than halfway past Y-axes and fitted tightly into next denticle. Section of central part above and below X-axis similar. Indentation in lower section of central part is distinct. Ray connection well developed. Rays robust and mostly straight, parallel to Y-axis or slightly directed posteriorly with sharply pointed end. Point of ray does not reach clear area. Ray apophysis prominent. Individuals with visible adoral spiral were not observed.

Comments: Biometric data corresponds to the description of the species ( Lom 1961, Van As and Basson 1989). In one specimen, the denticle morphology was similar to Trichodina compacta Van As et Basson, 1989 , the distal surface having a flat section running parallel to the border membrane.

Figures

Fig 1. Trichodina acuta Lom, 1961. A – silver impregnated photomicrograph; B – dentical diagram. Scale: 20 μm.