Neotropical Monogenoidea 64. Cosmetocleithrum falsunilatum sp. n. (Monogenoidea, Dactylogyridae) parasite of the gills of Megalodoras uranoscopus (Siluriformes, Doradidae) from the Solimões river, near Iquitos, Peru.

Megalodoras uranoscopus (Eigenmann & Eigenmann) (Siluriformes, Doradidae) (the giant-talking catfish or the giant-raphael catfish), from the Peruvian Amazon, hosts a new species of Cosmetocleithrum described herein as Cosmetocleithrum falsunilatum sp. n. The male copulatory organ of the new species closely resembles that of Unilatus spp. - with multiple tight loops and non-articulated accessory piece - which reveals its morphological uniqueness among members of Cosmetocleithrum. A phylogenetic analysis using 28S rDNA of available sequences suggests that Cosmetocleithrum is composed by two basal clades, one of them composed by sequences of the new species and C. trachydorasi.