Ceratomyxa

Type host: Sarpa salpa Linnaeus, 1758 goldline sea bream (Perciformes: Sparidae) Type locality: Mediterranean off Tunisia, Gulf of Tunis (36 ° 45 ’ N, 10 ° 15 ’ E). Site of infection: Within gall bladder Prevalence: The overall prevalence is 2.1 % (7 / 330) (Fig. 9). 0 % (0 / 120) fish infected in the Bay of Bizerte. The infection was restricted to the Gulf of Tunis with prevalence 3.33 % (7 / 210) distributed as following, 03 / 2012: 0 % (0 / 30); 04 / 2012: 23.3 % (7 / 30); 05 / 2012: 0 % (0 / 30); 06 / 2012: 0 % (0 / 30); 07 / 2012: 0 % (0 / 30); 08 / 2012: 0 % (0 / 30); 05 / 2013: 0 % (0 / 20); 06 / 2013: 0 % (0 / 10) (see Table 4). Mean intensity: 47.1 ± 11.5 spores / infected fish (++++) (Fig. 10) (see Table 4). Type-material: Digitized photos of syntype spores were deposited in the parasitological collection of the Museum National d’Histoire Naturelle (MNHN), Paris, Coll. No ZS 118. Description Vegetative stages. Trophozoïtes were freely floating in bile of the gallbladder in different stages of maturation and some seen attached to each others with their pseudopodia mostly short (Fig. 4 A), Plasmodia (n = 30) were both monosporous and disporous (Figs. 4 A – E), spherical to sub-spherical with variety of size, measuring 22.5 ± 4.23 (18.9 – 29.4) µm in length and 28.6 ± 6.43 (20.5 – 37.5) µm in width. Each plasmodium occupied one or two identical spores with some refractive granules. Spores (n = 30 fresh spores). Spores typical of the genus Ceratomyxa. Mature spores were elongated in sutural view (Fig. 4 F, 8 D) measuring in 7.32 ± 0.52 (6.52 – 7.92) µm in length and in 29.32 ± 1.5 (27.8 – 31.8) µm in breadth of central portion and 67.98 ± 2.44 (64.9 – 70.1) µm in total thickness. Enlarged valves were greatly extended and presented almost the half of the length of the spore. They are twisted forming with the basal plane of the spore an angle high-pitched in each side α = 35.6 ± 12.3 (28 – 57 °) (Fig. 4 F). Polar capsules were spherical and convergent 3.26 ± 0.23 (3 – 3.5) µm in length and 3.26 ± 0.23 (3 – 3.5) µm in width (n = 30). Numbers of turns of polar filament coil appeared to be 4 – 5. Sporoplasm finely granular and suture line perpendicular to the basal plane. Rarely, atypical spores with three valves, possessing three polar capsules, were observed (Fig. 4 H). Taxonomic affinities The recent isolate species has a specific feature with the presence of enlarged valves “ appendages ” which make it distinguishable from other confamiliar known Ceratomyxa spp. Over all the species of Ceratomyxa described in Mediterranean Sea or from different part of the world, the current species appears to be morphologically similar only to one species C. taenia Davis, 1917 described from the gall bladder of elasmobranch species Scoliodon terra-novae (Richardson, 1836) from the Atlantic Ocean (USA) (see Table 1). However, the present finding can be clearly separated from C. taenia by having spores larger in length and smaller in both breath of central part and total thickness. Furthermore, the average range of polar capsules of the current species is bigger than those of C. taenia and the angle between the shell valves and the basal plane is high-pitched for present form while it is right for C. taenia. On the other hand, the original report of C. taenia noted that this species has merely a disporic plasmodia on the contrary to the present form. In view of the morphological differences, host and locality records, this species is considered distinct and designated as unknown species identified by the first time in sparid host S. salpa from the Mediterranean Sea. Ecological notes During this study, the overall prevalence is 2.1 %. This myxosporean has a parasitic status as satellite species. Infection by Ceratomyxa sp. 1 was restricted only in Gulf of Tunis and this species was detected only in April with prevalence 23.3 % and mean intensity 47.1 ± 11.5 spores per infected fish (see Table 4). (measurements are in micrometer). Species Host Locality Spore Polar capsule Length Breadth of Thickness Length Width central portion Ceratomyxa sp. 1 Sarpa salpa Tunisia (Gulf of 7.32 29.32 67.98 3.26 3.26 (Present study) Tunis) (6.52 – 7.92) (27.8 – 31.8) (64.9 – 70.1) (3 – 3.5) (3 – 3.5)