Abstract
Four species of Monogenoidea (Dactylogyridae) are reported from the gills of freshwater fishes from Amazonas, Brasil, as follows: Anacanthorus spatulatus sp. n. from Colossoma bidens (Spix) and C. macropomum (Cuvier), and A. elegans sp. n., A. spiralocirrus melanopterus (Cope). Additionally, the status of the subfamily Anacanthorinae is discussed, and the diagnosis of Anacanthorus is emended.