Ceratomyxa lateolabrax, Zhao & Al-Farraj & Al-Rasheid & Song, 2015

Zhao, Yuanjun, Al-Farraj, Saleh A., Al-Rasheid, Khaled A. S. & Song, Weibo, 2015, Data on Ten New Myxosporean Parasites (Myxozoa, Myxosporea, Bivalvulida) from the Yellow Sea, China, Acta Protozoologica 54 (4), pp. 305-323 : 315

Ceratomyxa lateolabrax sp. n. ( Fig. 3F–J ; Table 2)

This organism was incorrectly marked as Ceratomyxa lateolabracis Zhao and Song, 2003 in the monograph “Pathogenic Protozoa in Mariculture” ( Song et al. 2003), which has not been described as a new species in that book. Thus, according to ICZN, the species should be an invalid name, hence, we “re-establish” and “re-describe” this form here.

Diagnosis: Trophozoites disporous, 18.7 × 12 µm in size; mature spores kidney shape, shell-valves with smooth surface, sutural line fine, 16.7 ± 1.2 (15.3–18.0) in thickness, 6.8 ± 0.4 (6.3–7.3) in length, posterior angle concave (162–180°); two smaller spherical polar capsules positioned anteriorly in a plane perpendicular to the sutural line, 2.1 ± 0.2 (2.0–2.5) in diameter; fine sporoplasm with one binuclear located in the spore cavity; coelozoic.

Host and site of infection: Gall bladder of Lateolabrax japonicus (Cuvier and Valenciennes 1828) .

Type locality: Coastal aquaculture waters off Jiaonan (35°48′N, 119°54′E) of the Yellow Sea , China. Salinity about 31‰, water temperature about 15°C .

Prevalence: Of the four fish examined, one was infected (25%).

Date of sampling: June 2, 1999.

Host symptom: Mix-infected with Ceratomyxa lomi sp. n., from only one fish host infected Ceratomyxa lateolabracis sp. n., pathogenicity unknown.

Type material: The holotype on an air-dried slide stained with Giemsa (Coll.: No. jn-19990602a), and a paratype slide stained with Giemsa (Coll.: No. jn- 19990602b), were deposited at the Collection Center of type-specimens, Chongqing KLAB, Chongqing Normal University , China .

Etymology: The species name recalls the host from which this species was originally isolated.

Description: Early stage plasmodia were not seen; later stages exhibited a peripheral layer of hyaline non-granular ectoplasm and thick granular endoplasm ( Fig. 3F ), enclosing the two developing spores, and were 18.7 × 12 µm in size. Mature spores: anterior margin slightly convex and posterior more or less concave; kidney shaped, shell-valves equal with a smooth surface and rounded ends from a sutural view, evident suture line ( Fig. 3G–J ), posterior angle was concave (162–180°). Two equal spherical polar capsules positioned anteriorly in a plane perpendicular to the sutural line; one binuclear sporoplasm located in spore cavity. No mucus appendage surrounded the spore. Measurements of spores are given in Table 2 (n = 20).

Comparison and comments: Considering the shape and size of spore, the current species resembles C. dubia Dunkerly, 1921 , but the ratio of thickness to length for the new species is slightly larger than that of C. dubia (2.5 vs. 2.2), moreover, the hosts and geographic distribution are different for the two parasites ( Lateolabrax japonicus from China off the Yellow Sea vs. Cottus dubalis from Plymouth, UK). In addition, this organism is easily distinguished from the other species of the genus Ceratomyxa , and can therefore be considered a new species for which the name Ceratomyxa lateolabracis sp. n. is proposed.

Figures

Fig. 3. Schematic illustrations of Ceratomyxa spp. A–E – Ceratomyxa lomi sp. n.; A – mature spore viewed from the perspective of the cap- sule; B–D – lateral view of mature spore; E – plasmodium with two mature spores; F–J – Ceratomyxa lateolabrax sp. n.; F – plasmodium with two spores; G–J – lateral view of mature spore; K–N – Ceratomyxa qingdaoensis sp. n.; K–L, N – showing a lateral view of a mature spore; M – lateral view of an immature spore. Scale bars: 10 µm.