Anacanthorus penilabiatus n. sp. is described from the
serrasalmid fish, Piaractus mesopotamicus (Holmberg, 1887),
cultivated in the Centro de Aquicultura, Universidade Estadual
Paulista. The new species is characterized by having a
relatively straight copulatory organ with a long olipo on the
distal margin and a median longitudinal flap, and a
copulatory ligament. The large size of the infrapopulations
of this species of parasite indicates that it should be
considered a potential agent causing losses in aquaculture of
the fish host.
