NEOTROPICAL MONOGENOIDEA .22. VARIATION IN SCLERODUCTUS SPECIES (GYRODACTYLIDEA, GYRODACTYLIDAE) FROM SILURIFORM FISHES OF SOUTHEASTERN BRAZIL

Specimens of Scleroductus are reported from the external surface of 4 siluriform catfish, Glanidium melanopterum Ribeiro (Auchenipteridae), Parauchenipterus striatulus (Steindachner) (Auchenipteridae), Pimelode lla sp. (Pimelodidae), and Rhamdia quelen (Quoy and Gaimard) (Pimelodi dae), collected from the Rio Guandu near Rio de Janeiro, State of Rio de Janeiro, Brazil. These reports represent new host and locality reco rds for Scleroductus species in the Neotropics. Morphometric variabili ty of the haptoral anchors and hooks of specimens from respective host s and additional diagnostic characters for the genus are presented.