The life cycle of Proctoeces maculatus (Looss, 1901) (Digenea, Fellodistomidae) was studied in Bizerte Lagoon (Tunisia). Three sequential hosts appear to be involved: the Mediterranean mussel Mytilus galloprovincialis Lamarck, 1819 (Mytilidae) as the first intermediate host; the polychaete Sabella pavonina Savigny, 1822 (Sabellidae), as the second intermediate host; and fishes (Lithognathus mormyrus (Linnaeus, 1758) (Sparidae), Trachinotus ovatus (Linnaeus, 1758) (Carangidae) and Sparus aurata Linnaeus, 1758 (Sparidae) as the definitive hosts. It should be noted that S. pavonina was recorded as second intermediate host for P. maculatus for the first time. Molecular confirmation of the morphological identification of the life-cycle stages of this digenean was obtained using partial 28S rDNA sequences. Comparative sequences revealed that the sporocysts and the metacercariae are conspecific but they diverged by 0.3% from the adults. The present results raised the possibility of the existence of cryptic species within the different developmental stages. However, all the present isolates differed from material from Archosargus probatocephalus in the Gulf of Mexico identified as P. maculatus.

SummaryA total of 39 digeneans species allocated to 28 genera in 12 families were recovered from 534 fi shes belonging to 14 species in three families (Carangidae, Mullidae and Sparidae) collected in the Bay of Bizerte off the coast of Tunisia. We provide a host-parasite list of records from this locality, including 63 host-parasite combinations. The Opecoelidae Ozaki, 1925 is the most diverse group with 12 species. The species richness of individual digenean genera in the Bay of Bizerte ranges from 1 -6 species. The mean number of 2.58 species per host indicates a relatively high digenean diversity in the Bay of Bizerte, which is related to its geographical location, its connection with the neighbouring Bizerte Lagoon and the nature of the bottoms of the littoral marine areas off the northern Tunisian coasts. This diversity is signifi cantly higher than that reported off the southern coast of Tunisia and distinctly lower than that observed for teleost hosts in the Scandola Nature Reserve off Corsica. Generally, the levels of infection in teleosts fi shes from the Bay of Bizerte are lower than those from the other two localities.

Morphological and molecular characterisation of specimens of Macvicaria spp. (Digenea: Opecoelidae) from five species of Mediterranean sparids (Teleostei: Sparidae) sampled in the Bizerte Lagoon and the Bay of Bizerte (Tunisia) revealed the presence of two species complexes designated as ''obovata'' and ''crassigula'' groups. Detailed comparative morphological and phylogenetic analyses revealed that two of the specimen sets, one from each complex, represent species new to science. M. maamouriae n. sp. from Sparus aurata L. and Lithognathus mormyrus (L.) appeared genetically similar to M. obovata (Molin, 1859) but differs in having a much larger ventral sucker relative to body width, a cirrus-sac extending dorsally to the posterior margin of the ventral sucker or more posterior, vitelline fields comprising distinctly more abundant vitelline follicles, reaching the level of the pharynx both ventrally and dorsally and confluent dorsally in the forebody, and an ovary contiguous with the anterior testis. Macvicaria bartolii n. sp. from Diplodus annularis (L.) and Spondyliosoma cantharus (L.) belongs to the ''crassigula'' group and is characterised by having almost exclusively dorsal vitelline follicles forming two non-confluent fields in the forebody. Additional morphological data are provided for Macvicaria dubia (Stossich, 1905), a poorly known parasite of Oblada melanura (L.). Morphological descriptions are associated with ITS1-5.8S-ITS2 and 28S rDNA sequences for the three Mediterranean species of Macvicaria Gibson & Bray, 1982. The results of our study suggest that further exploration of the species diversity within this genus should be based on both morphological and molecular data.