Ceratomyxa saurida, 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 : 318-319

Ceratomyxa saurida sp. n. ( Fig. 4A–G ; Table 2)

This organism was incorrectly marked as Ceratomyxa sauridae 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 not observed; mature spore deeply arcuate, anterior margin extremely convex and posterior margin concave from a sutural view. Arcuate mature spore with rounded valves ends and smooth surface, sutural line fine, 42.7 ± 2.5 (39.5–47) in thickness, 9.7 ± 0.5 (9.0–10.5) in length, posterior angle concave (130–165°); two smaller spherical polar capsules positioned in a plane perpendicular to the sutural line, 3.6 ± 0.4 (3.0–4.0) in diameter; one binuclear sporoplasm located in the spore cavity; coelozoic.

Type host and site of infection: Gall bladder of Saurida elongata (Temminck and Schlege 1846) .

Type locality: Coastal waters of the Yellow Sea off Qingdao, China (36°08′N, 120°43′E). Salinity about 32‰, water temperature about 14°C .

Prevalence: Of the 2 fish examined, 2 were infected (100%).

Date of sampling: June 10, 1999.

Host symptom: Unknown.

Type material: The holotype, on an air-dried slide stained with Giemsa (Coll.: No. qdSe-19990610a), and a paratype slide stained with Giemsa (Coll.: No. qdSe- 19990610b), were deposited in the Collection Centre of type-specimens, Chongqing KLAB, Chongqing Normal University , China .

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

Description: Trophozoites not seen. Mature spore deeply arcuate, anterior margin extremely convex and posterior margin concave; both ends of the valves rounded with a smooth surface, evident sutural line appearing straight from a sutural view ( Fig. 4A–G ), two symmetrical theca, equal in size and smooth, with elongated and rounded ends and an evident suture line ( Fig. 4A–D, G ). Posterior angle concave (130–165°). Two equal spherical polar capsules positioned anteriorly in a plane perpendicular to the sutural line; one binuclear sporoplasm located partly in the spore cavity ( Fig. 4B, G ). No mucus appendage surrounded the spore. Additionally, on the slides, some abnormal and immature spores were observed ( Fig. 4E–F ). Measurements of spores are given in Table 2 (n = 25).

Comparison and comments: Considering the morphology of the spore, the new species is similar to Ceratomyxa diloba Dogiel, 1948 , but the former is different from the latter in its dimensions: such as the thickness of the spore (39.5–47 in new species vs. 20–25.0 in C. diloba ), sutural diameter of the spore (9.0– 10.5 in new species vs. 7.0–8.0 in C. diloba ) and the diameter of the polar capsule (3.0–4.0 in new species vs. 3.0 in C. diloba ); moreover, the new taxon is distinguished from C. diloba by its different geographic location and host ( Saurida elongata from the Yellow Sea for the new organism vs. Sphoereides rubridalis and S. pardalis from the Japanese Sea for C. diloba ). To sum up the above, the present myxosporean is considered to be a new taxon.

Figures

Fig. 4. Schematic illustrations of Ceratomyxa spp. A–G – Ceratomyxa saurida sp. n.; A–D, G – lateral view of mature spore; E – lateral view of abnormal spore; F – lateral view of immature spore; H–L – Ceratomyxa simplex sp. n.; H, J – lateral view of mature spore; I – immature spore viewed from the perspective of the capsule; K–L – plasmodia with one spore; M–T – Ceratomyxa triacantha sp. n.; M–N, P – plasmodia with two spores; O, Q – early stage plasmodia with many nuclei; R–T – sutural view of mature spores. Scale bars: 10 µm.