TAPEWORMS (CESTODA, PROTEOCEPHALIDEA) OF HOPLIAS-MALABARICUS (PISCES,CHARACIFORMES, ERYTHRINIDAE) IN PARAGUAY - DESCRIPTION OF PROTEOCEPHALUS-REGOI SP-N, AND REDESCRIPTION OF NOMIMOSCOLEX-MATOGROSSENSIS

The erythrinid fish Hoplias malabaricus in Paraguay harbour two specie s of proteocephalid cestodes, Proteocephalus regoi sp. n. and Nomimosc olex matogrossensis Rego et Pavanelli, 1990. The former species differ s from most South American members of Proteocephalus from fishes by: 1 ) presence of a small apical organ, 2) distribution of vitellaria, whi ch do not reach to posterior margin of segment and 3) posterior positi on of vagina. Nomimoscolex matogrossensis is redescribed on the basis of type and recent material, with emphasis given to the morphology of genital organs and scolex, which possesses an apical organ. Both speci es possess a dense network of osmoregulatory canals in the postacetabu lar region of both scolex and neck. Proteocephalus regoi sp. n. is the first representative of the subfamily Proteocephalinae parasitizing e rythrinid fish.