Paranaella luquei gen. et sp. n. (Monogenea: Microcotylidae), a new parasite of Brazilian catfishes

Paranaella, a new microcotyline monotypic genus, is erected to accommodate Paranaella luquei sp. n., parasite of gill filaments from Hypostomus sp., Hypostomus regani (Ihering) and Rhinelepis aspera Spix et Agassiz (Loricariidae) from the Parana River, Brazil. The new genus is most closely related to Microcotyle Van Beneden et Hesse, 1863, Diplostamenides Unnithan, 1971 and Solostamenides Unnithan, 1971. From Microcotyle it differs mainly by having the genital atrium formed by a muscular ring with a concentric row of numerous elongate and straight spines; from Diplostamenides it can be distinguished by the unarmed and not differentiated cirrus and from Solostamenides it differs by the single vaginal pore and absence of larval hooks. Based on the male terminalia and on general distribution or absence of armature, Unnithan (1971) proposed a systematic partition of Microcotylidae, with 4 subfamilies and 18 genera. Mamaev (1986) presented a taxonomical composition of the Microcotylidae with 8 subfamilies and 39 genera. Despite the large number of microcotylid species reported from other geographical localities, only 15 species in 9 genera have been reported in South America (Kohn and Cohen 1998, Kohn and Paiva 1999), 14 from marine and one from brackish water fishes. During recent studies on the helminth fauna of fishes from the freshwater reservoir of the hydroelectric power station of Itaipu, Parana River, a new species of a new genus of Microcotylinae was found on the gills of two different genera of catfishes.