Cairaeanthus gen. n. (Cestoda, Rhinebothriidea), with the Description of Two New Species from Dasyatis pastinaca in the Black Sea and the Sea of Azov
Two new species were identified among cestodes collected from Dasyatis pastinaca (Linnaeus, 1758) in the Black Sea and the Sea of Azov. Their morphology corresponds in the most characters to the descriptions of Phyllobothrium lactuca van Beneden, 1850 and P. gracilis Wedl, 1855 by L. Borcea (Borcea, 1934) and T. P. Pogorel'tseva (Pogorel'tseva, 1960) from the same host and seas. However, some morphological characters of these cestodes (namely, the marginal loculi on the pedicellate bothridia, cephalic peduncle, absence of the apical sucker and post-poral testes, genital pore opening marginally, close to posterior end of proglottid) correspond to diagnosis of Rhinebothriidea. Since the species from the Black Sea and the Sea of Azov did not fit diagnoses of any known genera currently belonging to Rhinebothriidea, the new genus, Cairaeanthus Kornyushin et Polyakova, gen. n., with two species, C. ruhnkei Kornyushin et Polyakova, sp. n. and C. healyae Kornyushin et Polyakova, sp. n., is established. Cairaeanthus gen. n. differs from Anthocephalum Linton, 1890 in absence of apical sucker, posteriorly bifid bothridia and vitelline fields interrupted by the ovary, not extending in the posterior end of the proglottid. The new genus can be distinguished from Rhinebothrium Linton, 1890, Echeneibothium van Beneden, 1850, Rhabdotobothrium Euzet, 1953, Rhinebothroides Mayes, Brooks et Thorson, 1981, Scalithrium Ball, Neifar et Euzet, 2003 by the absence of facial loculi on the bothridia and by numerous vitelline follicles, stopping at the anterior margin of the ovary; from Rhodobothrium Linton, 1889 - by absence of post-poral testes, and from Spongiobothrium Linton, 1889 - by numerous vitelline follicles, stopping at the level of ovary. C. ruhnkei sp. n. differs from C. healyae sp. n. in the lengths of the strobila, the cephalic peduncle and the bothridia pedicel, in size of marginal loculi and the ovary, in the number of the proglottids and the testes in the proglottid, and in the structure of genital atrium. Two new species are differentiated also from the morphologically related species Phyllobothrium pastinacae Mokhtar-Mocamouri, Zamali, 1981. Examined type specimens of P. pastinacae were attributed to Rhinebothiidea based on a set of morphological characters. However, they appear to differ from all known Rhinebothriidea, including the species from the genera Anthocephalum Linton, 1890 and Cairaeanthus gen. n. Taxonomic position of P.pastinacae needs further identification.