Digenea community structure of the Salema, Sarpa salpa (Linnaeus, 1758) (Teleostei, Sparidae), from the Central coast of Algeria.

The main goal of the current work was to describe and analyse the Digenean community structure in Sarpa salpa. A total of 114 specimens of S. salpa were collected from the Central Coast of Algeria at six localities. The fish were immediately transported to the laboratory to be examined for digeneans. From 107 of the 114 S. salpa examined, a total of 8,722 specimens of seven species belonging to three families were recovered. Among them, Robphildollfusium fractum and Mesometra orbicularis were the most prevalent and abundant species. Moreover, Lepocreadium album was found for the first time in S. salpa from the coast of Algeria, and Centroderma spinosissima and Wardula capitellata represent new parasites to the Algerian digenean fauna that infect teleost fish. The component community of these Digeneans is characterised by R. fractum as its dominant species representing 62% of the total number of collected Digeneans, as well by a Shannon diversity index (H') and Dominance Simpson index (D) of 1.03 and 2.23, respectively. According to Spearman's correlation test, Mesometra brachycoelia and W. capitellata were negatively correlated to the host biological factors. On the other hand, R. fractum showed a positive correlation between its mean abundance and the total length of the fish. With these findings, we provided the component structure of the Digenean fauna of S. salpa and highlighted their diversity, contributing to the biodiversity of the parasitic Platyhelminthes in Algeria.

Diversity of digeneans parasitizing Mullus barbatus and Mullus surmuletus (Teleostean, Mullidae) off the coast of Algerian.

Mullus barbatus and Mullus surmuletus (Perciformes, Mullidae) are a common marine teleost of great commercial importance in many coastal areas. We studied the communities of Digenea species in two congeneric Mullidae hosts collected on the Algerian coast in the southern Mediterranean. Five hundred and seven M. barbatus and one hundred and twenty-three M. surmuletus were examined. During this work, we collected six species of parasitic Digenea which are related to five different families: Hemiuridae represented by Lecithocladium excisum, Fellodistomidae by Proctoeces maculatus and which is reported only from M. surmuletus, Derogenidae by Derogenes latus, Monorchiidae by Proctotrema bacilliovatum and finally Opecoelidae represented by two species Opecoeloides furcatus and Poracanthium furcatum. A critical systematic study revealed an apparent overlap in morphometric data of the six Digenean species from two host fishes. Therefore, the two mullet species are likely to share the same parasite community, and the stenoxenic specificity of Digenean parasites is briefly argued. Prevalence values showed that in the midst of six hundred and thirty Mullidae, one hundred and ninety-six are parasitized (31.11 %). Statistical tests showed that the most parasitized fish hosts are M. surmuletus with a high prevalence value (47.15 %), and on the other hand, they proved that small fish are more parasitized than others. Also, the lack of homogeneity between the different parasites is reported. We also note that the use of factorial correspondence analysis (FCA) allowed us, for the first time to highlight the distribution of the parasite species identified in the two mullets according to the seasons.

New Insights Into the Genetic Variability of Fasciola Hepatica (Trematoda) in Algeria and Relationships with Other Geographic Regions Revealed By Mitochondrial DNA.

This study aims to investigate the level of genetic variability of Fasciola hepatica flukes isolated from cattle in Algeria and to determine the phylogenetic and phylogeographic relationships with sequences isolated worldwide. Mitochondrial (Cytochrome c Oxidase subunit I gene - COI) and nuclear markers (Internal Transcribed Spacers of nuclear ribosomal DNA - ITS) for 24 F. hepatica flukes isolated from 12 cattle in North Algeria were characterised. Only two haplotypes were obtained for the COI gene, resulting in a low level of genetic variation. The analysis of variation among the COI sequences isolated from around the world did not show high levels of genetic divergence, and the phylogenetic analysis revealed a genetic similarity among F. hepatica isolates from different areas of the world. The analysis of the ITS region showed a low level of variability, which prevented obtaining informative phylogenetic and phylogeographic results. The present study also revealed that specimens of F. hepatica are genetically similar in different hosts, indicating that the genetic structure among populations of this parasite is not influenced by the host species. The low levels of genetic variation for COI and ITS regions among fluke isolates from all continents are consistent with a common origin for the flukes' worldwide distribution.

Description of a new species of rhinebothriidean tapeworm from the skate Dipturus batis in the Mediterranean Sea.

Examination of rajid skates off the Algerian coast in the Mediterranean Sea revealed that three of the 33 Dipturus batis Linnaeus, 1758 examined harboured a new tapeworm species: Echeneibothrium algeriensis n. sp. This new species, collected from the anterior half of the spiral valves, is described on the basis of morphological data from light and scanning electron microscopy. The new species differs from previously described Echeneibothrium species by details of the scolex and loculi, total length, the length of the myzorhynchus, the number of proglottides, and the number of testes. Comparison of the diets of the ten skate species common in the Mediterranean basin indicates some varying degree of overlap, suggesting that host specificity in this host-parasite system is determined by other host and/or ecological variables such as adaptations of the parasites to their respective hosts, either on the morpho-anatomical level, in physiological characteristics of the parasite's habitat, in the trophic requirements for the successful transmission of the parasite, or in adaptations to the behavioural characteristics of the host. Furthermore, restricted overlap of E. algeriensis n. sp. with congeners in parasite assemblages of D. batis indicates some structuring according to attachment-site preferences. However, attachment-site preferences are not explained solely by morphological compatibility between bothridia and villi. This study reiterates the need to examine multiple factors synergistically in studies on host specificity of parasites, and the need to examine the parasite fauna of hosts across their entire geographical range in order to truly appreciate the biodiversity they harbour.

[Acanthobothrium minus n. sp. (Tetraphyllidea: Onchobotriidae) parasite of Raja asterias (Elasmobranchii: Rajidae) in Mediterranean Sea]. / Acanthobothrium minus n. sp. (Tetraphyllidea: Onchobotriidae) parasite de Raja asterias (Elasmobranchii: Rajidae) en Méditerranée.

Among tetraphyllidean cestodes, parasitic in the spiral valve of Raja asterias Delaroche, colected from Algerian coasts, we obtained an onchobothriid of the genus Acanthobothrium, differing from all species of Acanthobothrium previously reported from Rajidae from Mediterranea and european Atlantic coast. This Cestode is characterized by its very small size (1-2 mm), its number of segments of the strobila (4-8), the morphology and size of hooks, the limited number (17-25) of testes and ovarian morphology. Together, these features places this Acanthobothrium in group "2" as defined by Ghoshroy & Caira (2001). We describe this onchobothriid as Acanthobothrium minus n. sp.