Neotropicla monogenoidea. 36. Dactylogyrids from the gills of Rhamdia guatemalensis (Siluriformes : Pimelodidae) from cenotes of the Yucatan Peninsula, Mexico, with proposal of Ameloblastella gen. n. and Aphanoblastella gen.n. (Dactylogyridae : Ancyrocephalinae)

Ameloblastella gen. n. and Aphanoblastella gen. n. are proposed for dactylo gyrids from the gills of pimelodid catfishes (Siluriformes) in the Neotropi cal Biogeographical Region. Species of Ameloblastella and Aphanoblastella a re characterized on the bases of gonadal position, hook shank morphology, p resence/absence of eyes and eye granules, and morphology of the male reprod uctive system. Two species of Urocleidoides (sensu lato) and 1 of Vancleave us are transferred to Ameloblastella as A. chavarriai (Price, 1938) comb. n . (type species), A. mamaevi (Kritsky and Thatcher, 1976) comb. n. and A. p latensis (Suriano and Incorvaia, 1995) comb. n., respectively. Three specie s of Urocleidoides (sensu lato) from pimelodid catfishes are transferred to Aphanoblastella as A. travassosi (Price, 1938) comb. n. (type species), A. robustus (Mizelle and Kritsky, 1969) comb. n. and A. mastigatus (Suriano, 1986) comb. n.