A new species of Sciadicleithrum (Monogenea: Ancyrocephalinae), gill parasite of Geophagus brasiliensis (Quoy & Gaimard) (Teleostei: Cichlidae) from reservoirs in the State of Parana Brazil

Sciadicleithrum frequens n. sp. is described from the gills of the acara, Geophagus brasiliensis (Cichlidae), from nine reservoirs in the State of Parana, Brazil. The new species differs from the others members of Sciadicleithrum in the following features: dorsal anchors more than twice as long as the ventral anchors and hook pair 5 reduced in size. Sciadicleithrum frequens n. sp. is similar to species of this parasite genus from South America by having the male copulatory organ comprising less than 2 rings, and to species of Sciadicleithrum from Central America and southeast Mexico by the presence of longitudinal lateral grooves on the shafts and points of the ventral and dorsal anchors. This new species is the first species of Sciadicleithrum in South America with longitudinal lateral grooves on shafts and point of the ventral and dorsal anchors. It is the first dactylogyrid described from G. brasiliensis, and it is the first species of Sciadicleithrum described from Southern Brazil.