Leiotrocha patella (Cúenot, 1891)

Van As, Liesl L., Basson, Linda & Van As, Jo G., 2017, Mobiline Peritrichs (Ciliophora) Limpets Collected from the Gills of African, Acta Protozoologica 56 (4), pp. 245-254 : 250

Description of Leiotrocha patella from West African limpets ( Figs 1E and F , 2B, D, F )

Host: Patella depressa Pennant, 1977

Other host: Cymbula safiana (Lamarck, 1819)

Locality: Gorée Island (10°30′S, 20°30′E), Bay of Dakar , Senegal, West Africa

Reference material: 93/11/13-16; 93/11/15- 9 in the collection of the Department of Zoology & Entomology, University of the Free State, Aquatic Parasitology division

Position on host: Gills of limpets

Short cylindrical body ( Fig. 1E ) with high elevated convex peristome. Some individuals appear more compressed than others. Adoral spiral makes about 405° turn ( Fig. 2F ). Outside peristomial lip, haplo- and polykineties show separate rows of kinetosomes before entering buccal cavity. Inside infundibulum polykinety slopes downwards before dividing into three infundibular polykineties. Germinal row supports polykinety just after entering infundibulum. Haplokinety makes another 180º turn, before entering infundibulum and making a three-quarter turn. At the end of haplokinety an impregnable band is visible. Ends of both kineties come close together before reaching cytostome ( Fig. 3 ).

Aboral ciliary wreath ( Fig. 1E ) consists of single row of closely spaced marginal cilia, compound ciliary girdle and single basal ring, three groups of cilia separated by two prominent membranes ( Fig. 1E ). Adhesive disc with ring of scopular cilia ( Fig. 1F ), cilia 2 µm in length, grouped in pairs. Kinetosomes of “lost” scopular cilia form a complete ring. Denticles smooth, overlapping like roof tiles ( Fig. 2B ). Anterior apophysis fitting closely against preceding denticle. Distal margin parallel to bor- der membrane. Proximal margin not parallel to distal margin, sloping in posterior distal direction. Central part tapers to sharp point, extending past next denticle adorally for about one quarter length of denticle. Distal central part forming indentation at point of articulation with following denticle. Striated membrane consists of radial pins, extending past denticle.

Cytoplasm filled with symbiotic algae ( Fig. 2F ), hindering observations of internal organelles. Nuclear apparatus ( Fig. 2D ) consists of A-shaped macronucleus and round to oval micronucleus. Macronucleus has two lateral lobes with thin connections, meeting in round to oval robust central part. One side of lobes almost fused, with opposite ends wide apart. Central part lies closer to aboral side of body, whilst lateral lobes are situated more adorally. Micronucleus small, but prominent in closed part of macronucleus lobes, situated near robust central part. Body measurements and denticle information are summarised in Table 1.

Figures

Fig. 1. Scanning electron micrographs of Leiotrocha patellae (Cuénot, 1891) collected from Cellana radiata capensis (Gmelin, 1791) (A–D) from Bazley, South Africa and Patella depressa Pennant, 1777 (E–F) from Gorée Island, West Africa. A and E: Body form with aboral (arrows) and adoral ciliary wreath; B:Adoral view of spiral and ciliary wreath just visible; C: Denticle ring (arrow), soft part dissolved, and striated membrane exposed (arrow); D and F: Scopular cilia (arrow). Scale bar:A, B, E, F = 10 µm; C, D = 2 µm.

Fig. 2. Light micrographs of Leiotrocha patellae (Cuénot, 1891) collected from Cellana radiata capensis capensis (Gmelin, 1791) (A, C, E) from Bazley, South Africa and Patella depressa Pennant, 1777 (B, D, F) from Gorée Island, West Africa.A and B: Denticle ring; C and D: Nuclear apparatus – arrow indicate micronucleus; E: Adoral spiral, infundibulum; F: Adoral spiral and body inclusions (arrow). Scale bar:A, B, E, F = 10 µm; C, D = 2 µm.

Fig. 3. Line drawing of infundibulum of Leiotrocha patellae (Cuénot, 1891) collected from Patella depressa Pennant, 1777 from Gorée Island, West Africa. hk – haplokinety; im – impregnable band, p – infundibular polykineties, pk – polykinety.