No abstract

Cercaria cerastodermae I, a digenean parasite of Cerastoderma edule, was recorded for the first time in the Atlantic Ocean off the Iberian peninsula. Sporocysts were present in the hemolymph of the digestive gland, gonad, gills, and foot of the mollusc. Most of the cercariae present within sporocysts were encysted as metacercariae. The corresponding adult stages were obtained after experimental infection of several Diplodus sargus artificially reared in fish farms and that had previously been protected against natural infections. Numerous adult specimens of Monorchis parvus were collected in Diplodus annularis along the French Mediterranean coast. Comparison of wild and experimental adults allowed the adult stage of Cercaria cerastodermae I to be identified as M. parvus. Another monorchid, Monorchis monorchis, a parasite of Spondyliosoma cantharus, was found in the same Mediterranean area and compared with M. parvus. Additionally, ITS1 nuclear ribosomal DNA sequences of C. cerastodermae I and of the adults collected in naturally infected D. annularis and S. cantharus were obtained. Sequence data indicate that C. cerastodermae I corresponds to the adult of M. parvus found in D. annularis and is clearly distinct from M. monorchis found in S. cantharus.

Macvicaria obovata (Molin) n. comb . i s redescribed from Sparus aurata off the Mediterranean coast of France and a neotype is designated . Specimens from Oblada melanura off Israel may belong to the same species. It is mainly characterized by the uterine extension between the ovary and the anterior testis and the lack of a vitelline confluence in the forebody . M. maillardi n. sp. is also described from Sparus aurata off the southern coast of France . Its uterus does not pass between ovary and testes and the vitelline fields are confluent in the forebody . M . crassigula (Linton) n . comb . is redescribed from Diplodus annularis, D . sargus, D . vulgaris, Pagellus erythrinus and Sparus pagrus off Corsica, Calamus bajonado off Bermuda, Spicara smaris, D . annularis off Yugoslavia, D . sargus off Israel, and D . cervinus, Sparodon durbanensis and Cheilodactylus fasciatus in the SW Indian Ocean . It is similar to M . maillardi, but differs in being smaller, having a greater sucker ratio and a larger pharynx . It may well be a species-complex . M. dubia (Stossich) n. comb . is redescribed from Oblada melanura off Corsica and Yugoslavia . It is similar to M . maillardi and M . crassigula, but has a more anteriorly situated genital pore . ResumeMacvicaria obovata (Molin) n . comb . est redecrit a partir d'individus parasites de Sparus aurata des c6tes mediterraneennes francaises (? et de Oblada melanura d'Israel) ; un neotype est designe . Cette espece est essentiellement caracterisee par des boucles uterines presentes entre l'ovaire et le testicule anterieur ainsi que par des glandes vitellines ne fusionnant pas dans la region preacetabulaire . M. maillardi n. sp . est aussi decrit chez S. aurata (France meridionale) ; chez cette espece, l'uterus ne s'engage pas entre l'ovaire et le testicule anterieur tandis que les vitellogenes confluent largement dans 1'espace preacetabulaire . M. crassigula (Linton) n . comb . est redecrit a partir d'exemplaires provenant de Diplodus annularis, D . sargus, D . vulgaris, Pagellus erythrinus et Sparus pagrus de Scandola (Corse), Calamus bajonado des Bermudes, Spicara smaris, D . annularis de Yougoslavie, D . sargus d'Israel, D . cervinus, Sparodon durbanensis et Cheilodactylus fasciatus du Sud-ouest de 1'Ocean Indien . Cette espece est proche de M. maillardi : elle en differe par une plus petite taille, un rapport ventousaire plus eleve et un pharynx plus volumineux . Vraisemblablement, it s'agit la d'un complexe d'especes . M. dubia (Stossich) n . comb ., parasite de Oblada melanura, est redecrit a partir d'un materiel provenant de Corse (Scandola) et de Yougoslavie . Cette espece, voisine de M . maillardi et de M. crassigula, s'en distingue par un orifice genital situe plus anterieurement .

The morphology and ecology are described for four sibling species of digenean metacercariae: Meiogymnophallus minutus (Cobbold 1859), M. strigatus (Lebour 1908) from the estuarine cockle Cerastoderma edule L. and M. fossarum (Bartoli, 1965) and M. rebecqui (Bartoli, 1983) comb. nov. from the brackish water lagoon cockle C. glaucum (Poiret). Although occupying different sites within the two species of cockle, both M. minutus and M. fossarum infections result in pathological effects that may cause heavy host mortality. Remarkably, they also result in an inversion of the cockles in situ in the sand such that predation by the final host species is enhanced.