Nine Pteromylaeus bovinus (F., Geoffroy St. Hilaire) (Euselachii: Myliobatinae) from the Tunisian coast were examined l'or ectoparasites during 1995, 1996 and 1997. A monogenean found on the gills of seven host specimens is described as a new species and a new genus, Heliocotyle, is proposed to accomodate it. The presence of a single sclerotized haptoral structure on the dorsal surface of the haptor leads us to place this species in the Heterocotylinae Chisholm, Wheeler ct Beverley-Burton, 1995. The genus Heliocotyle is characterized by a haptor with only one dorsal structure and seven loculi, six being subdivided by pseudosepta. Heliocotyle kartasi sp. n. is the type and the only species in this genus.
Plectanocotyle major sp. n. (Monogenea: Polyopisthocotylea: Plectanocotylidae) is described from Chelidonichthys obscurus (Bloch et Schneider, 1801) collected from the Mediterranean coasts (Tunisia and France). The new species is compared to Plectanocotyle gurnardi collected on Chelidonichthys gurnardus and the only other valid species in the genus Plectanocotyle. The new species differs from P. gurnardi by the clamp size (137 µm vs 64 µm for clamp length and 110 µm vs 60 µm for clamp width, respectively) and the length of the male copulatory organ (107 µm vs 144 µm, respectively). Species of the Plectanocotylidae seem to be characterized by an oioxenic specificity.
Progrillotia pastinacae Dollfus, 1946 (Cestoda: Trypanorhyncha) is redescribed from the spiral valve of Dasyatis pastinaca (Linnaeus) (Dasyatididae) from the coast of France. Progrillotia dasyatidis sp. n. is described from the spiral valves of Dasyatis tortonesei Capapé (Dasyatididae) from the Mediterranean in the Gulf of Gabès (Tunisia) and D. pastinaca from the Bassin d'Arcachon (France). The new species differs from congeners in having, on the tentacles, a single rather than two rows of intercalary hooks and fewer testes. The generic definition is emended based upon the new species, the redescription of P. pastinacae Dollfus, 1946 and re-examination of the type specimen of P. louiseuzeti Dollfus, 1969. Important additional characters noted are that the tentacular hooks are solid, a prebulbar organ is present and that there are gland cells attached to the retractor muscle within the bulb. A cladistic analysis suggests that the genus is closely allied with the Eutetrarhynchidae. Progrillotia dollfusi Carvajal et Rego, 1983 is provisionally excluded from the genus as the adult of the species is unknown and a key character of the genus is that the testes are pre-ovarian.