In total, 404 fishes of 34 species caught in the Weddell Sea were examined, including four specimens of skates, Bathyraja maccaini and Bathyraja sp., and 23 specimens of the gadiform fish, Macrourus whitsoni (the only three species infected with adult Cestoda). Skates were infected with four representatives of the order Tetraphyllidea, Marsupiobothrium awii sp. n., Anthocephalum siedleckii (syn. Phyllobothrium siedleckii), Anthocephalum arctowskii (syn. Phyllobothrium arctowskii), Oncobothrium antarcticum. The three last species were first described in the South Shetland Islands area. Phyllobothrium siedleckii from B. maccaini (new host) and P. arctowskii from Bathyraja sp. are transferred to the genus Anthocephalum and their descriptions are emended. Marsupiobothrium awii sp. n. from B. maccaini is characterised by: apolytic strobila; scolex with four sessile, jar-like bothridia, each with opening provided with a ring of muscles and submarginal sucker; 120-150 testes; vagina with dilatation in proximal part and sphincter present distally; eggs 0.016 x 0.017 mm. Differential diagnosis with remaining species of the Marsupiobothrium is given. Oncobothrium antarcticum was found in B. maccaini (new host). M. whitsoni was infected with one pseudophyllidean species, Parabothriocephalus johnstoni, previously known as only from the same host in the Indian sector of the Antarctic Ocean.