Redescription of the tapeworm Monticellia amazonica de Chambrier et Vaucher, 1997 (Cestoda, Proteocephalidea), a parasite of Calophysus macropterus (Siluriformes, Pimelodidae) from the Amazon River

The proteocephalidean cestode Monticellia amazonica de Chambrier et Vaucher, 1997 (nom. nov. for Nomimoscolex piracatinga Woodland, 1935), a parasite of Calophysus macmpterus (Lichtenstein, 1819) (Siluriformes, Pimelodidae), is redescribed on the basis of type specimens and recently collected material from the Amazon River near the type localities in Brazil, and from Peru. This insufficiently known taxon is most similar to M. ventrei de Chambrier et Vaucher, 1999 from Pinirampus spp. from Paraguay and Brazil in having almost indistinguishable internal longitudinal musculature formed by a very few (5-15) tiny bundles of muscle fibres. Monticellia amazonica differs from M. ventrei in the shape of proglottids (much more elongate in the former taxon), absence of medially situated vitelline follicles at the ovarian level (present in M. ventrei) and the number of testes (175-233 in M amazonica vs. 222-325 in M ventrei).