Redescription of two cestodes (Eucestoda: Proteocephalidea) parasitic in Phractocephalus hemioliopterus (Siluriformes) from the Amazon and erection of Scholzia gen. n

Abstract

Scholzia emarginata (Diesing, 1850) comb. nov. [synonyms: Tetrabothrium emarginatum Diesing, 1850; Nomimoscolex emarginatus (Diesing, 1850) Rego et al., 1999; Myzophorus pirarara Woodland, 1935; Nomimoscolex pirarara (Woodland, 1935); Proteocephalus pirarara (Woodland, 1935) de Chambrier & Vaucher, 1997) is redescribed on the basis of the type series of M. pirarara and newly-collected material from the siluriform fish Phractocephalus hemioliopterus in the Amazon River, Brazil. The new monotypic genus Scholzia gen. n. differs from the remaining genera of the subfamily Proteocephalidae by (1) the morphology of the scolex, (2) strobilar features such as the presence of four posterior lobes forming a velum, (3) the ovary and the vitellaria medullary with cortical projections into the velum, and (4) the vitelline follicles posteriorly converging medially at the ovarian level. Proteocephalus hemioliopteri de Chambrier & Vaucher, 1997 [synonyms: Myzophorus woodlandi Rego, 1984; Nomimoscolex woodlandi (Rego, 1984) Rego & Pavanelli, 1992] ) is redescribed on the basis of the type series of M. woodlandi and newly-collected material from the same host and locality. The morphology and distribution of microtriches of some areas of the body surface of both species are studied and compared. Three types of microtriches were observed in S. emarginata and 2 types of microtriches in P. hemioliopteri. The distribution of microtriches analysed was not useful to discriminate genera but it may be useful as a supplementary character to distinguish species.