Neotropical Monogenoidea. 46. Three new species from the gills of introduced aquarium fishes in India, the proposal of Heterotylus n. g. and Diaphorocleidus n. g., and the reassignment of some previously described species of Urocleidoides Mizelle & Price, 1964 (Polyonchoinea: Dactylogyridae).

Three new species of the Dactylogyridae are described from aquarium fishes collected in India and two new genera are proposed: Heterotylus heterotylus n. g., n. sp. from Hypostomus sp. (Loricariidae), Diaphorocleidus armillatus n. g., n. sp. from Gymnocorymbus ternetzi (Characidae) and Urocleidoides vaginoclaustrum n. sp. from Xiphophorus helleri (Poeciliidae). Heterotylus n. g. is characterised by species having overlapping gonads (testis posterodorsal to the ovary), a mid-ventral vaginal aperture, a copulatory complex consisting of a relatively straight copulatory organ unarticulated to a complex accessory piece, erect acute hook thumbs, unexpanded hook shanks, dorsal and ventral anchor/bar complexes and absence of well-defined basal roots of the ventral anchors. Diaphorocleidus n. g. includes species with overlapping gonads (testis posterodorsal to the ovary), submarginal sinistral vaginal pore, a copulatory complex comprising a coiled (counterclockwise) copulatory organ unarticulated to an accessory piece, protruding depressed hook thumb, hook shank with two subunits (proximal subunit expanded), dorsal and ventral anchor/bar complexes and V-shaped bars. The following new combinations are proposed: D. affinis (Mizelle, Kritsky & Crane, 1968) n. comb. (syn. U. affinis Mizelle, Kritsky & Crane, 1968), D. kabatai (Molnar, Hanek & Fernando, 1974) n. comb. (syn. U. kabatai Molnar, Hanek & Fernando, 1974) and D. microstomus (Mizelle, Kritsky & Crane, 1968) n. comb. (syn. U. microstomus Mizelle, Kritsky & Crane, 1968).