A revision of Neobenedenia Yamaguti, 1963 (Monogenea: Capsalidae) including a redescription of N. melleni (MacCallum, 1927) Yamaguti, 1963

Neobenedenia Yamaguti, 1963, a genus of capsalid (benedeniine) monogeneans lacking a vagina, is redefined. The generic diagnosis is amended to include previously unused characters like the path of tendons in the haptor from extrinsic muscles in the body, the presence and form of a marginal valve, the shape of the anterior attachment organs, the arrangement of musculature at the posterior (proximal) end of the penis sac and the presence of a pair of sphincters in the female reproductive tract. On this basis, the generic composition is reduced from 10 to six species. Species considered valid are: N. melleni (MacCallum, 1927) Yamaguti, 1963; N. adenea (Meserve, 1938) Yamaguti, 1963; N. isabellae (Meserve, 1938) Yamaguti, 1963; N. longiprostata Bravo-Hollis, 1971; N. muelleri (Meserve, 1938) Yamaguti, 1963; N. pacifica Bravo-Hollis, 1971. Neobenedenia girellae (Hargis, 1955) Yamaguti, 1963 and N. paragueraensis Dyer, Williams and Bunkley-Williams, 1992 are considered synonyms of N. melleni. Species formerly ascribed to Neobenedenia, namely N. manilae Velasquez, 1982 and N. vermiculariacola Gupta and Khanna, 1975 are considered species inquirendae. A key to valid species is presented. The type species, N. melleni, is redescribed based on the original specimens of MacCallum and N. isabellae is redescribed based on material from the type locality. Since no types of N. melleni were designated, a lectotype and paralectotypes are assigned. The problem of host designation and locality for the types of N. melleni sensu MacCallum is discussed. A study of more than 80 specimens now considered to be N. melleni has permitted comments on its apparent variety of forms and its low host-specificity according to the current revision. N. melleni is now recorded from over 100 species of teleosts in more than 30 families from five different orders. Material reported previously as N. melleni off Chile from Seriola mazatlana, Thunnus thynnus orientalis and Seriola sp. are identified here as Benedenia seriolae (Yamaguti, 1934) Price, 1939. The host-specificity and geographic distribution of species in the revised genus is discussed.