Ceratomyxa gouletti n. sp. (Myxosporea: Ceratomyxidae), a parasite of the red scorpionfish Scorpaena scrofa (L.) from Tunisian waters.

Ceratomyxa gouletti n. sp. is a new parasite described from the gallbladder of the red scorpionfish Scorpaena scrofa (Scorpaeniformes: Scorpaenidae) collected from La Goulette in the Northeast of Tunisia. The parasite develops disporic plasmodia, elliptical to ovoid in shape, measuring up to 33.1 ± 3.6 (28.0-38.2) µm in length and 12.5 ± 2.1 (11.3-14.0) µm in width. Mature spores are elongated transversely and crescent-shaped with rounded ends and unequal shell valves, measuring 8.1 ± 1.27 (7.2-9.0) µm in length and 32.0 ± 2.5 (27.0-38.2) µm in thickness. Sutural line is straight and visible between valves. Polar capsules are subspherical with 3.15 ± 0.63 (2.7-3.6) µm long and 1.9 ± 0.14 (1.8-2.0) µm wide. Posterior spore angle is slightly concave 160°-175°. Molecular analysis based on the small subunit 18S rDNA sequence shows that C. gouletti n. sp. is different from all other ceratomyxid species DNA sequences in GenBank. Phylogenetic trees clustered the new species with long-branching Ceratomyxa species, and it was closely related to the species Ceratomyxa longipes from two gadid fish hosts with 89% bootstrap support.

Scanning electron microscopy study of Strabax monstrosus von Nordmann, 1864 (Copepoda: Chondracanthidae) from Tunisian waters and histopathological study of its effects on host.

Strabax monstrosus von Nordmann, 1864 (Copepoda: Chondracanthidae) is an ectoparasite and it was recently recorded from small red scorpionfish, Scorpaena notata Rafinesque, and red scorpionfish, Scorpaena scrofa L., collected from Tunisian coastal waters. Copepod females were found deeply embedded in the branchial cavity reaching the cardiac region with their mouth-parts. Observations of females and males using scanning electron microscopy showed a number of morphological features that have been previously overlooked or incompletely presented. In this study, we report for the first time the fine structures of appendages, mouthparts, external genital organs (nuptial organs), and other structures of male and female Strabax monstrosus. Histopathological study showed lesions in the cardiac region of the host fish which is the target site of the parasite. The presently reported finding is the first record of Strabax monstrosus from Scorpaena notata and Scorpaena scrofa collected from Tunisian waters.

Updated inventory and distribution of free-living flatworms from Tunisian waters.

Records of free-living flatworms (turbellarians) from Tunisian waters are scattered. Based on new material and published accounts, an annotated checklist of free-living flatworm species from Tunisian waters is provided. A total of 29 species is recorded, including 18 species with new material and 11 species only from literature records. For each species, information on systematics, habitats and distribution is supplied, together with taxonomic or biological remarks. Three species, the acotylean polyclads Cestoplana rubrocinta Lang, 1884 and Comoplana agilis (Lang, 1884) as well as the marine triclad Cercyra hastata Schmidt, 1861 are recorded for the first time in Tunisia. The controversial occurrence of the leptoplanid polyclad Leptoplana tremellaris in the Mediterranean is supported with histological sections and embryological data. The proseriate Monocelis fusca Örsted, 1843 previously reported from Tunisia is considered to be a misidentification.By presenting a checklist of the recorded species, this work summarizes our current knowledge of the turbellarian fauna diversity in Tunisia, providing baseline data for future biogeographical, ecological, behavioral and evolutionary investigations.

Morphological description and phylogeny of Ceratomyxa scorpaeni n. sp. (Myxosporea: Ceratomyxidae) infecting the gallbladder of Scorpaena porcus (L.) (Scorpaeniformes: Scorpaenidae) from the bay of Bizerte in Tunisia.

A new marine myxosporean species Ceratomyxa scorpaeni n. sp. is described using morphological characteristics and small subunit ribosomal DNA (rDNA) sequence data. The parasite was found infecting the gallbladder of Scorpaena porcus Linnaeus, 1758 collected from the Bay of Bizerte. Mature plasmodia were disporous free floating in the bile. Spores were transversely elongated and crescent-shaped with unequal shell valves and measured 7.6 ± 0.2 (7.2-8.0) µm in length and 32.8 ± 0.3 (21.6-44.0) µm in thickness. Two sub-spherical polar capsules equal in size, situated at the same level and measured 3.0 ± 0.2 (3.0-3.2) µm in length and 2.4 ± 0.3 (2.3-3.3) µm in width. The infection with C. scorpaeni n. sp. was prevalent throughout the year with a maximum prevalence of infection during spring and summer. Molecular analysis of the SSU rRNA gene confirmed the parasite as a new member of the genus Ceratomyxa and showed close relationship with the species of Ceratomyxa infecting the gallbladders of Sparidae from the Mediterranean Sea. This is the first report of Ceratomyxa species from the gallbladder of S. porcus in Tunisian coastal waters.