Ceratomyxa lophii Afonso-Dias, Kalavati, Mackenzie & Mackenzie, 2007, n. sp.

Ceratomyxa lophii n. sp. (Figures 1–3)

Material studied

Host: Lophius piscatorius L.

Site of infection: gall bladder.

Locality, dates and depths: (1) 58°51ˏN, 07°35ˏW (NW of Scotland), 30 March, 2000, 250m; (2) 58°45ˏN, 07°49ˏW (NW of Scotland), 30 March, 2000, 400m. Prevalence: (1) 6 of 16 (37%); (2) 8 of 26 (31%). Host length range: (1) 41–64 cm; (2) 45–66 cm. Collection number: 2005:7:1:1.

Description

Trophozoite (or pseudoplasmodium) (Figure 1) spherical or slightly ovoid, di- or tri-sporous, with short finger-like pseudopodia. Endoplasm distinct, finely granular. Dimensions, based on 6 fixed specimens: 20.0– 26.8 x 16.0–20.0.

Spore (Figures 2, 3) asymmetrical, banana-shaped, one end more pointed than the other. Valves unequal, smooth, larger valve slightly bent. Sutural line straight, thin. Sporoplasm binucleate, extends below polar capsules. Polar capsules spherical, subterminal. Polar filament tightly coiled, with 7–8 coils. Dimensions, based on 30 fixed spores, as ranges with means ± SD in parentheses: spore length 5.6–8.0 (7.1 ± 0.6); spore thickness 30.0–39.6 (34.9 ± 2.7); thickness of larger valve 18.0–25.0 (21.0 ± 2.6), and of smaller valve 12.0–18.0 (14.8 ± 1.2); diameter of polar capsule 3.0–5.4 (4.1 ± 0.7); polar capsule length: spore length = 1: 1.4–2.6; spore length: spore width = 1: 3.5–6.8.

Discussion

Eiras (2006) listed 147 nominal species of the genus Ceratomyxa from fish hosts, the most common site of infection being the gall bladder. One species of Ceratomyxa, C. appendiculata, was described by Thélohan (1895) from both L. piscatorius and L. budegassa off the Atlantic and Mediterranean coasts of France and was subsequently reported from L. budegassa in the Adriatic Sea by Lubat et al. (1989). It was most recently reported by Maillo et al. (2004) from 58.2% of L. budegassa caught in the western Mediterranean and we recently found what appeared to be the vegetative stages of C. appendiculata in the gall bladder of one L. piscatorius caught off the west coast of Portugal (unpublished result). Ceratomyxa lophii n. sp. differs markedly from C. appendiculata in having unequal spore valves, and in the form of the trophozoite, which in C. appendiculata is polymorphic with from one to six pointed pseudopodia.

Unequal spore valves have been described from other species of Ceratomyxa. The seven species with the most marked differences in size between valves are compared with C. lophii in Table 1. In only one other spe-cies— C. inaequalis Doflein, 1898 —is the difference in size and shape between the two valves close to that observed in C. lophii n. sp.. Ceratomyxa inaeqaulis was described from the labrid fishes Symphodus mediterraneus and S. tinca in the Mediterranean Sea. Its spores are similar in gross dimensions to those of C. lophii n. sp., but the difference in length between the two spore valves is much smaller. The form of the trophozoite is also different between the two species, that of C. inaequalis being teardrop-shaped with usually one long pointed pseudopodium, in contrast to the spherical or ovoid shape and short blunt pseudopodia of C. lophii n. sp. Given these marked morphological differences and the fact that the two species have been reported from different host species and from locations a considerable distance apart, we consider them to be separate species.

Ceratomyxa lophii was found only in samples of L. piscatorius caught at the edge of the continental shelf to the northwest of the Outer Hebrides. It may therefore have a more restricted and northerly distribution than its congener C. appendiculata.

Species of Ceratomyxa Spore Polar capsule Host Locality Length Thickness Length Width

C. lophii n sp. 5.6–8.0 30.0–39.6 3.0–5.4 3.0–5.4 Lophius piscatorius Northwest of Scotland

C. acanthuri Kpatcha, Die- 10.0–12.0 16.0–18.0 2.0–3.2 2.0–3.2 Acanthurus monroviae Senegal

bakate, Faye and Toguebaye,

hippoglosus, Reinhardtius,