Molecular evidence for the existence of species complexes within Macvicaria Gibson & Bray, 1982 (Digenea: Opecoelidae) in the western Mediterranean, with descriptions of two new species.

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.