Two species of the genus Proteocephalus (Cestoda:
Proteocephalidae) were collected in fishes from the Parana
River. Proteocephalus vazzolerae n. sp. from Piaractus
mesopotamicus and Proteocephalus chubbi n. sp. from Gymnotus
carapo are new species, and are described and illustrated.
Proteocephalus vazzolerae n. sp. is characterized mainly by
the number of testes and the development of vitellaria.
Proteocephalus chubbi n. sp. can be differentiated from its
congeners by a combination of characters which include, number
of testes, number of proglottids, strobila length, scolex
shape and disposition of vitellaria. This is the first record
of proteocephalidean in P. mesopotamicus and G. carapo.