Trichodina cribbi Dove, 2005

S. MARCOTEGUI, Paula, Basson, Linda & R. MARTORELLI, Sergio, 2016, Trichodinids (Ciliophora) of Corydoras paleatus (Siluriformes) and Jenynsia multidentata (Cyprinodontiformes) from Argentina, with Description of Trichodina corydori n. sp. and Trichodina jenynsii n. sp., Acta Protozoologica 55 (4), pp. 249-257 : 252-253

Trichodina cribbi Dove and O´Donoghue, 2005

( Figs 2A–B ; 4B )

Description. Medium-sized, freshwater trichodinid: body diameter, 49.5–69.8 (61.4±6.6); diameter of adhesive disc, 40.5–59.9 (51.2±5.8); denticulate ring diameter, 24.6–37.8 (32.8±3.8); width of border membrane 4.0–5.6 (4.9±0.6); denticle number, 27–37 (33); number of radial pins per denticle, 9–11(11); denticle span, 11.1–15.3 (13.7±1.1); denticle length, 3.6–6.0 (5.2±0.8); centre of adhesive disc clear with clear rounded or slightly notched perimeter containing a few to a large number of dark granules, rarely forming patches; blade length, 5.1–6.4 (5.8±0.5). Anterior blade margin slants gradually downwards towards apex, touching Y+1 axis. Apex rounded. Blade apophysis not visible. Distal blade margin higher than tangent point. Tangent point delicate. Posterior blade margin strongly curved and L-shaped, deepest point on same level as apex. Posterior projection weakly developed, but present. Section connecting blade and central part robust, clearly distinguishable from blade. Central part squat and well developed with rounded tip, fitting tightly into preceding denticle, extends halfway to Y-1. Central part above and below the X-axis not similar, section above with slanted edge, whilst section below more angular in shape. Central part width is 2.1–3.5 (2.8±0.4). Prominent indentation present in lower central part. Section connecting central part and ray very robust. Rays strongly developed, irregular in shape, tapering sharply to a rounded point. Rays prominently curved posteriorly, directed towards Y-1 axis with ends crossing Y-1 axis. Ray apophysis not observed. Ray length 3.5–6.1 (4.7±0.7). Ratio of denticle above to denticle below x axis more than one (1.2–1.3). Nuclear apparatus and adoral cilia not observed.

Host: Jenynsia multidentata Jenyns, 1842 ( Cyprinodontiformes : Anablepidae )

Locality: Samborombón River (Brandsen), Buenos Aires, Argentina (35°10′39.79″S, 58°15′29.70″W)

Site of infection: gills, skin and fins

Voucher specimens: MLP-Pr100

Remarks. Trichodina cribbi Dove and O’Donoghue, 2005 is characterized by a large circular central inclusion and approximately 28 denticles and with a blade length slightly greater than the ray length. The morphometric characteristics of specimens studied here correspond well with T. cribbi as provided by Dove and O’Donoghue (2005).

This species was originally described by Dove and O’Donoghue (2005) from gills of fishes of the Black Mountain Peninsula, Lake Burley, Griffin, and Canber- ra, Australia. Nevertheless, in C. paleatus during this study, T. cribbi was found also on the skin and fins.

This is the second report of this species worldwide, the first record from the Americas and from a new posi- tion on the host. The present report also expands on the host range, adding a new host family.

Figures

Fig. 2. Photomicrographs of silver nitrate-impregnated adhesive discs of trichodinids from Jenynsia multidentata. A–B – Photomicrographs of Trichodina cribbi. Scale bars: 10 μm.

Fig. 4. Diagrammatic drawings of denticles of trichodinids. A – Trichodina corydori n sp. from Corydoras paleatus. B – T. cribbi from Jenynsia multidentata. C – T jenynsii n sp. from J. multidentata. D – T. pediculus redrawn from Kazubski and Migala (1968). E – T. pediculus redrawn from Gaze and Wooten (1998). F – T. pediculus redrawn from Kazubski (1991c).