A histochemical study using lectin methods was performed on myxosporean parasites from vastly different fish hosts from marine and fresh waters. Six biotinylated lectins were used (WGA, SBA, BS-I, Con-А, UEA-I and SNA). The binding paltem of Con-A and WGA revealed the presence of mannose and/or glucose, and N-acetyl-D-glucosamine respectively, in polar capsules and valves of most of the myxosporea assayed. Thus, chitin may be present in polar capsules and/or valves of myxosporean spores. The BS-I binding pattern showed the presence of a-!)-galactose and/or N-acetyl-D-galactosamine residues in polar capsules of Kudoa sp., Zschokkeìla mugilis Sitjà-Bobadilla et Alvarez-Pellitero, 1993 and Leplotheca sp., and in the valves of the latter. Scarce amounts of N-acetyl-D-galactosamine and/or α-D-galactose were demonstrated by SBA binding in Sphaerospora dicentrarchi Sitjà-Bobadilla et Alvarez-Pellitero 1992, Leplotheca sp. and Kudoa sp. valves, and in Leptotheca sp. polar capsules. The UEA-I staining indicated the absence ofa-L-fucose in all the myxosporea assayed except in Leptotheca sp. N-acety!neuraminic acid was detected with SNA in the polar capsules and sporoplasms of Polysporoptasma sparis Sitjà-Bobadilla et-Alvarez-Pellitero, 1995 and in the polar capsules and valves of Kudoa sp. These results indicate that, although Myxosporea may have conserved carbohydrate structures, some of them can show significantly different binding patterns, which may be useful in diagnostic and functional studies.
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.