attenuata Davis (1917) Scoliodon terranovae flagellifera Davis (1917) Carcharhinus mesospora Davis (1917) Cestracion streptospora Davis (1917) Choetodipterus faber robusta Fujita (1923) tenuis Fujita (1923) Hippoglossoides lepidopusi Meglitsch (1960) Lepidopus candatus auerbachi Kabata (1962) Clupea harengus swaisi Abđel-Ghaffar et al . (2008a) Saurida undosquamis carcharhini Glees Carcharhinus melanopterus Myxosporea (Cnidaria: Myxozoa) infecting the saddled seabream Oblada melanura (L. 1758) (Teleostei: Sparidae) and the painted comber Serranus scriba (L. 1758) (Teleostei: Serranidae) in Tunisia Laamiri, Sayef Zootaxa 2017 4269 1 61 100 [151,298,1821,1847] Myxosporea Ceratomyxidae Ceratomyxa Animalia Bivalvulida 8 69 Myxozoa genus     Host:  Serranus scribaLinnaeus, 1758painted comber ( Perciformes: Serranidae).  Locality: Mediterraneanoff Tunisia, Sidi Daoud, Gulf of Tunis( 37° 01’ N 10° 55’ E). Site of infection:Within gall bladder.  Prevalence:The overall prevalence is 11.7% (21/180). The frequency of infection is distributed as following, 03/2012: 3.3% (1/30); 04/2012: 6.7% (2/30); 05/2012: 20% (6/30); 06/2012: 20% (6/30); 07/2012: 13.3% (4/30); 08/2012: 6.7% (2/30) ( Table 10).   Mean intensity:154±44 spores/20µl bile/infected fish (++++++) ( Table 10).   Vouchers:Digitized photos of spores are deposited in the parasitological collection of the Museum National d’Histoire Naturelle ( MNHN), Paris, Coll. No. ZS136.  Morphological description. Vegetative stages.No vegetative stages are observed. The bile is turbid due to the presence of large number of free floating spores with bile salts and cell debris. Infrequently, the spores of this parasite are remarked in the bile mixed with scarce  Triangulasp. infection ( Fig. 3H).   FIGURE 3.Photomicrographs of  Ceratomyxa sp. 1from the gall bladder of  Serranus scriba. (A–F) Variable forms of fresh mature spores in sutural view presenting the pyriform polar capsules ( pc), the straight suture line ( sl), the sporoplasmic nuclei ( sn), the capsulogenic nucleus ( cn) and the unequal valves. Scale bar = 10 µm.  Myxospores.Spores typical for the genus  Ceratomyxa(n = 30 fresh spores). Mature spores are crescentshaped to arched with anterior margin convex and posterior slightly concave one in sutural view, transversely elongate in lateral view ( Figs. 3A–I, 8A–B) measuring 8.6±1.1 (7.0–10.8) µm in length and 52.6±5.8 (42.8–61.1) µm in thickness. Posterior angle is slightly concave to slightly convex 153.8±16.9 (120–174°). Two elongated shell valves strikingly attenuate towards the extremities with pointed ends in sutural view ( Figs. 3A–H, 8A) and with rounded ends in lateral view ( Figs. 3I, 8B). They are sub-equal in some spores but the most, are unequal in size, with one tapering to a significantly greater degree than the other ( Figs. 3A–I, 8A–B). The longer valve measuring 34.5±3.0 (30.6–40.5) µm while the shorter one 27.7±3.8 (20.6–33.2) µm. The suture line is straight and visible TABLE ³.Comparison of the spore measurements of the present  Ceratomyxa sp.]ex  S. scribawith taxonomic affinities species (measurements are in µm). Abbreviations: SL, Spore Length;, Spore Thickness; PCL, Polar Capsule Length; PCW, Polar Capsule Wiđth; ND, Not Determineđ.  Species Host (s) Locality Spore Polar capsule   SL ST PCL PCW  Ceratomyxasp.](Present stuđy)  Serranus scriba Tunisia(Gulf of Tunis) 8.6 52.6 4.2 3.6 (7/10.8) (42.8/61.1) (4/4.5) (3.2/4)  sphaerulosa Thélohan (1892) *Mustelus vulgarisFrance (Roscoff, Monaco) (10/12) (90/100) (6/7) 5  *Galeus canis   Clupea harengus  Scullium canicula    attenuata Davis (1917)  Scoliodon terranovaeUSA (Atlantic Ocean) 9 115 4.5 4.5  flagellifera Davis (1917)  Carcharhinussp.USA (Atlantic Ocean) 12 118 6 6  mesospora Davis (1917) * CestracionUSA (Atlantic Ocean) 8 (50/60) 4.5 4.5  zygaena    Cestracion tiburo    streptospora Davis (1917)  Choetodipterus faberUSA (Atlantic Ocean) 4 (34/39) 3 3   robusta Fujita (1923) *AtherestesJapan (Sea of Japan) (18/20) (115/120) 5.6 4.5  evermani    Lepidopsetta mochgorei   Microstomus kitt    tenuis Fujita (1923) * HippoglossoidesJapan (Sea of Japan) (10/15) (108/112) (4/5) (3/4)  hamiltoni    Limanda aspera Microstomus kitt   orientalisDogiel (1948) Shulman *Sardinops sagaxRussia (Sea of Japan) (7/11) (33/72) 3 3.3 1966) melanosticta   Clupea harengus pallasi    porrectaDogiel (1948) Shulman *Gymnacanthus Russia( Seaof Japan) (4/6) (50/60)  3 3 1966) herzensteini   Myoxocephalus brandti   Bero elegans    lepidopusi Meglitsch (1960)  Lepidopus candatusNew Zealanđ (Pacific Ocean) 9.9 91(72.6/99) 3(2.2/3.3) 3(2.2/3.3) (7.7/11)   auerbachi Kabata (1962)  Clupea harengusScotlanđ (North sea) 10 75(57/92) 5(3/6) 5(3/6) (7/13)   swaisi Abđel-Ghaffar et al. (2008a)  Saurida undosquamisEgypt (Ređ sea) 7.8 51.5(43/55) 3.2 1.8 (7/9) (3/4) (1.5/2)  carcharhiniGlees-on & Ađlarđ  Carcharhinus melanopterus Australia(Great Barrier 10 58.1 3.8 3.7 2011) Reef) (9/11.5) (46/77.5) (3.5/4) (3.5/4) Original host.  between valves ( Figs. 3C–D). Sporoplasm homogenous with numerous sporoplasmosomes, are symmetrically situated, but extending only a short distance into each valve and contain two nuclei which each one occupied one side and rarely migrated both to one side ( Figs. 3A–B). One capsulogenic nucleus is situated beneath one of the polar capsules ( Fig. 3B). Two polar capsules are pyriform conspicuously separated from each other and measuring 4.2±0.2 (4.0–4.5) µm in length equaling 52.5% of spore length and 3.6±0.2 (3.2–4.0) µm in width (n = 30), they are positioned medially in the apex of spore in sutural view ( Figs. 3A–I, 8A) and centrally of spore cavity in apical view. The polar filament forms four to five turns arranged along the longitudinal axis of the capsule. Occasionally, aberrant spores with 3 polar capsules and 3 valves are observed among the spores ( Fig. 3J).  Taxonomic affinities.Our attempts at identification of the recent finding species follow the same considerations mentioned in the preceding species. In Mediterranean Sea, none of the  Ceratomyxaspp. recorded in the study of Siau & Sakiti (1981)from some serranids in Southeast Tunisian coasts resemble morphologically or overlap within the measurements range of the current species ( Table 6). The only Mediterranean marine  Ceratomyxathat shows some superficial similarity in shape and form to our species, is  C. sphaerulosa Thélohan, 1892reported from the gall bladders of numerous unrelated fishes hosts from Bergen in Norwayand from Roscoff and Mediterranean off  Monaco, France(Table 3). The recent species distinguishes from  C. sphaerulosaby having two unequal shell valves and smaller spores and polar capsules. Furthermore, the sporoplasm deposits asymmetrically within the spores of this species on the contrary to the current studied form. According to the parasitological reports, several species of  Ceratomyxahave been properly reported from Serranidaefamily among the wide word;  C. angusta,  C. gemmaphora Meglitsch, 1960,  C. epinephela,  C. reniforma,  C. guishanensisWu, Wu & Dingke, 1993,  C. brayi,  C. whippsi, C. gleesoni, C. hooperi, C. nolani,  C. yokoyamaiGunter & Adlard, 2009, C.  hamour Mansour, Al-Qahtani, Al-Quraishy & Abdel-Baki, 2014and most recently  C. husseini Abdel-Baki, Mansour, Al-Qahtani, Al Omar & Al-Quraishy, 2015( Table 6). From all these above mentioned congeneric species, the recent species is superficially similar in form to  C. angusta,  C. epinephelaand  C. yokoyamai. Nevertheless, only  C. angustahas unequal shell valves as the present species, but its spores and spherical polar capsules seem to be significantly smaller. Likewise, both  C. epinephelaand  C. yokoyamaiare thinner in all levels and posses each one two spherical polar capsules. Among the remaining  Ceratomyxaspp. from clearly distinct geographical areas and hosts, C. sp. 1is superficially closer to numerous species from unrelated marine fishes:  C. attenuata,  C. flagellifera,  C. mesospora,  C. streptospora Davis, 1917,  C. robusta,  C. tenuis Fujita, 1923,  C. orientalisand  C. porrectaDogiel, 1948(cited from Shulman 1966),  C. lepidopusi Meglitsch, 1960(previously  C. elongata, see Gunter & Adlard 2010),  C. auerbachi Kabata, 1962,  C. swaisi Abdel-Ghaffar, Ali, Al-Quraishy, Al-Rasheid, Al-Farraj, Abdel-Baki & Bashtar, 2008aand  C. cacharhini Gleeson & Adlard, 2011(Table 3). However, every time the recent finding myxosporean exhibits one or more distinguishing characteristics. It differentiates from  C. attenuataby having thinner spores and two pyriform polar capsules. Furthermore, the shell valves of this later species are unequal and dissimilar while one being about 15 shorter than the other and ending abruptly, the longer valve tapering gradually to a point disagreeing with the morphological features of our species.  C. flagelliferais the closest to the current species in form and shape, however it has larger and thicker spores. Besides, its polar capsules are typically spherical and bigger. Although, most of the morphometric measurements coincide between the present species and  C. mesospora, this later possess two equal valves and two spherical polar capsules. Furthermore, the sporoplasm are asymmetrically situated within its spores and sometimes being entirely confined to the larger valve on the contrary to the current finding.  C. streptosporaappears to have shorter and thinner spores compared to those of the present species and its polar capsules are spherical.  C. robustaresembles to our species only in shape but no measurements overlap between both species. The spores of  C. tenuisare much bigger.  C. orientalishas two smaller polar capsules. The spores of  C. porrectaare shorter, its shell valves are thinner and contain two spherical smaller polar capsules. The spores of both  C. lepidopusiand  C. auerbachiare thicker than those of our species, its valves are equal in size and its polar capsules are spherical.  C. swaisiis separated from the current species by having smaller polar capsules. Moreover, the shell valves of the present finding are unequal in size and much narrower than those of  C. swaisi. The average range of spores of  C. carcharhiniis bigger than that of our species and their polar capsules are spherical. In addition,  C. carcharhinihas morphologically a strongly convex anterior end and more concave posterior one compared to the slightly convex anterior end and slightly posterior one of the recent finding and is, therefore a distinct species. In light of these differences with closely related species and since no  Ceratomyxaspecies recorded thus so far is identical, we propose to mention the recent myxozoan  Ceratomyxa sp. 1as a special species has found infecting, by the first time, the gall bladder of  S. scribain Mediterranean Sea. 1503377473 Tunisia Host 37.016666 Mediterranean 1184 10.916667 Locality 8 69 1 Tunis 1503377477 Coll. No. ZS MNHN 9 70 1 MNHN 1503377466 Tunisia Tunis 10 71 1 Tunis 1503377474 1966-03-03 Russia Sea 10 71 1