Ceratomyxa pallida Thélohan, 1895

Laamiri, Sayef, 2014, New observations on Myxozoa of the goldline sea bream Sarpa salpa L. 1758 (Teleostei: Sparidae) from the Mediterranean coast of Tunisia, Zootaxa 3887 (2), pp. 157-190 : 162

Ceratomyxa pallida Thélohan, 1895

Type host: Sarpa salpa Linnaeus, 1758 goldline sea bream ( Perciformes : Sparidae )

Other host: Boops boops Linnaeus, 1758 bogue

Type locality: Mediterranean off Monaco, France.

Other localities: Mediterranean off Tunisia: Location 1: Gulf of Tunis (36°45’N, 10°15’E); Location 2: Bay of Bizerte (37°20’ N, 9°53’ E).

Site of infection: Within gall bladder

Prevalence: The overall prevalence is 20% (66/330) ( Fig. 9 ). At location 1, the prevalence of infection is 22.86% (48/210) distributed as following, 03/2012: 13.3% (4/30); 04/2012: 20% (6/30); 05/2012: 30% (9/30); 06/ 2012: 23.3% (7/30); 07/2012: 20% (6/30); 08/2012: 10% (3/30); 05/2013: 40% (8/20); 06/2013: 50% (5/10). At location 2, the prevalence of infection is 15% (18/120) distributed as following, 03/2013: 13.3% (4/30); 04/2013: 13.3% (4/30); 05/2013: 16.7% (5/30); 06/2013: 16.7% (5/30) (see Table 4).

Mean intensity: 126.9 ± 20.8 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 129.

Description

Vegetative stages. Numerous spherical trophozoïtes found often in massive groups with variety of size ( Fig. 2 A). They were seen floating in the bile and contained within several refractile granules and inner generative cells ( Fig. 2 A), Monosporic plasmodia (n = 30) ( Figs. 2 C–D), mostly spherical to amoeboid, measuring 22.9 ± 2.1 (20–25) µm in diameter. The amoeboid plasmodia showed a pseudopodia extending from its periphery ( Fig. 2 C) while other spherical seemed disadvantaged from any type of pseudopodia ( Figs. 2 C,D)

Spores (n = 30 fresh spores). Mature spores were slightly crescent-shaped with anterior margin convex and posterior slightly concave in sutural view ( Figs. 2 E–F,H,8B), measuring 7.32 ± 0.61 (6.5–8) µm in length and 28 ± 1.5 (26–30) µm in thickness. Posterior angle was concave to straight 160.9 ± 4.6 (154–170°). Two valves, roughly equal, smoothly ovoid in lateral view tapering gradually toward the end, which one rarely more attenuated than the other. Straight sutural line visible between valves. A binucleate sporoplasm with several visible sporolasmosomes occupied almost the entire spore cavity and rarely dispersed asymmetrically ( Fig. 2 E). Polar capsules were almost spherical, 2.95 ± 0.47 (2.5–3.6) µm in length and 2.92 ± 0.39 (2.5–3.6) µm in width (n = 30). The polar filament formed four turns arranged along the longitudinal axis of the capsule.

Remarks

C. pallida Thélohan, 1895 was firstly described from two members of Sparidae family B. boops (L.) and S. salpa (L.) from the Mediterranean off France. The original description of Thélohan (1895) was poor and limited to some measures. No schematic draw has been published for this species by that author or by Georgévitch (1916) who found the same parasite in the same two hosts from the Mediterranean off Monaco. Auerbach (1912), in his study, was uncertain as the Ceratomyxa species found in the gallbladder of Gadus merlangus (Linnaeus, 1758) from the Bergen in Norway, was C. pallida based on dimensions of vegetative forms which were disporous and some mature spores. Likewise, Davis (1917) mentioned in his study a very close similarity between C. monospora Davis, 1917 found in the gall bladders of Peprilus alepidotus (Linnaeus, 1766) and Prionotus evolans (Linnaeus, 1766) from Atlantic Ocean and C. pallida Thélohan, 1895 based only on the size of the trophozoïtes without determination of the mature spores. In the study of Meglitsch (1960), C. pallida and other species have been omitted from the list of ceratomyxids because of the lack of information. Furthermore, in the synopsis of the Ceratomyxa compiled by Eiras (2006), the description of C. pallida did not conform to the data noted in the original report as the vegetative forms were almost spherical and not the mature spores ( Thélohan 1895; Kudo 1920). During this survey, the trophozoïtes of C. pallida are spherical and monosporous in congruent with the original description of Thélohan (1895). However, the dimensions of the present form show a little difference as the plasmodia are larger and the spores are more longer than those originally noted.

Ecological notes

During our investigation, the overall prevalence of C. pallida infection is 20%. It has a parasitic status as less frequent species (10% ≤ Prevalence ≤ 50%). Infection by C. pallida was present during the entire period of sampling in both localities. In Gulf of Tunis, the infection started from March and increased gradually to June with greater prevalence 20% in 2012 and 50 % in 2013. However, it decreased after from June to August. Generally, prevalence and mean intensity values increased from March to June then diminished till August. In Bay of Bizerte, the infection was detected with no significant difference between months. The highest prevalence was noted in May 16.7% and still constable to June (see Table 4). In both localities, mean intensity of C. pallida appeared severe with 126.9 ± 20.8 spores per infected fish ( Fig. 10 ).

Figures

FIGURE 2. Photomicrographs of Ceratomyxa pallida from the gall bladder of Sarpa salpa. (A) Spherical trophozoïtes (T) in different size attached to each other in massive groups. (B) Spherical trophozoïte with numerous inner generative cells (gc). (C – D) monosporic plasmodia (p) with fine granular protoplasm, notice the presence of filopodia (f) at the amoeboid plasmodium. (E) Fresh mature spores in sutural view presenting the polar capsules (pc) and sporoplasm nuclei (sn). (F) Fresh mature spore in lateral view. (G) Fresh mature spore in apical view. (H) Mature spore stained with Giemsa showing the distinct spherical polar capsule with visible suture line. Scale bar = 20 µm in A, C – D; 10 µm in B, E – H.

FIGURE 9. Prevalence of species of myxozoans from 2 localities, Gulf of Tunis and Bay of Bizerte. The total prevalence determined within the pooled sample of 330 goldline sea bream (Sarpa salpa).

FIGURE 10. Mean intensity ± standard deviation of species of myxozoans infecting Sarpa Salpa.