Ceratomyxa pallida Thélohan, 1894

Thabet, Aouatef, Abdel-Baki, Abdel-Azeem S., Harrath, Abdel Halim & Mansour, Lamjed, 2019, Morphological and molecular aspects of Ceratomyxa ghannouchensis n. sp. and C. pallida Thélohan 1894 infecting the bogueı Boops boops (l.), Journal of Natural History 53 (9), pp. 541-556 : 545-548

Ceratomyxa pallida Thélohan ı 1894 ( Figure 2 )

Myxospore morphology

The mature myxospores typical of the genus Ceratomyxa were crescent-shaped. The anterior margin was archedı and the posterior margin was concave. Valves were equal with rounded and tapered ends. A slightly curved sutural line was visible between the two valves. The sporoplasm filled half of the myxospore cavity. The myxospores measured 6 ± 0.5 (5 – 7) µm in length and 28.5 ± 2.5 (26 – 33) µm in thickness. The polar capsules were sphericalı equal in size and measured 3 ± 0.3 (2.7 – 3.3) in diameter. Polar filaments in the capsule were not discernible.

Vegetative stage

Spherical to elongated monosporousı disporous and trisporous plasmodia were found floating in the bile. The measurements of the plasmodia were 29 ± 5.3 × 10 ± 2.5 µm. A schematic drawing of the myxospore and plasmodiaı based on light microscope observationsı is shown in Figure 2 .

SSU rDNA sequence

A consensus sequence of 1547 bp of the SSU rDNA was generated from three different sequenced samples and was submitted under accession number FJ710895 . Two sequences from the six sequenced clones were identical to the sequences obtained from samples individually infected by C. pallida . The sequence of C. pallida has 97.5% of similarity with C. ghannouchensis ı and 94.4% with C. tunisiensis Thabetı Mansourı Al Omar and Tlig-Zouariı 2015 .

Taxonomic summary

Location in the host. Coelozoicı in the bile

Type host. Bogueı Boops boops (Linnaeus) ( Perciformes : Sparidae ) site of infection. Lumen and wall of the gallbladder.

Prevalence. Sixty-three per cent (99 out of 157 examined specimens).

Type location. Ghannouch in the Gulf of Gabèsı (33°56 ′ 37.6 ″ Nı 10°04 ʹ 42.7 ″ E)ı south of Tunisia.

Deposited. Photosyntype (ZS141)ı one air-dried slide stained with Giemsa (ZS142) and myxospores in absolute ethanol (ZS143) were deposited in the parasitological collection of the Museum National d ’ Histoire Naturelleı Parisı collection.

Molecular data. Partial SSU rDNA sequence was deposited in GenBank (accession number KR086361 ).

Remarks

The present species was morphologically compared with all Ceratomyxa spp. infecting fish of the family of Sparidae in the Mediterranean or in other marine ecosystems ( Table 1 ). Based on mature myxospores measurementsı the present Ceratomyxa differs from all species previously reported infecting other Sparidae species worldwide. Compared to other species occurring in this region of the Mediterranean Seaı the present species has high similarity with C. tunisiensis Thabetı Mansourı Al Omar and Tlig-Zouariı 2015 ı recently reported from two Carangidae in the same localityı Ceratomyxa aegyptiaca Yemmenı Martonı Eszterbauer and Bahriı 2012 from solea aegyptiaca Chabanaud ( Pleuronectiformes : Soleidae ) from a Tunisian coastal lagoon. Ceratomyxa pallida appears larger than C. tunisiensis (28.5 vs 23 µm) and smaller than C. aegyptica (28.5 vs 51.3 µm). Regarding the host fishı Thélohan in 1894 recorded Ceratomyxa pallida from the gall bladder of the bogue Boops boops (L)ı in the Mediterranean ( France) and the Adriatic Sea ( Croatia). Based on the myxospore measurements and host speciesı we considered the present Ceratomyxa species identical to C. pallida . About this speciesı no data were known regarding myxospore morphologyı vegetative stages or molecular characteristics until now.

Figures

Figure 2. Ceratomyxa pallida from the gall bladder of Boops boops. (a) Fresh mature myxospore; and (b) disporousı (c) monosporous and (d) trisporous plasmodia. (e)ı (f) and (g) Line drawings of the mature myxosporeı disporous and trisporous stages respectively. Scale bars = 10 µm.