NEOTROPICAL MONOGENOIDEA .30. ANCYROCEPHALINAE (DACTYLOGYRIDAE) OF PIRANHA AND THEIR RELATIVES (TELEOSTEI, SERRASALMIDAE) FROM BRAZIL - SPECIES OF CALPIDOTHECIUM GEN-N, CALPIDOTHECIOIDES GEN-N, ODOTHECIUM GEN-N, AND NOTOTHECIOIDES GEN-N

Two species of Calpidorthecium, 2 species (1 new) of Calpidorthecioide s, 1 new species of Odothecium, and 1 new species of Notothecioides (D actylogyridae, Ancyrocephalinae) are described and/or reported from th e gills of 4 species of Serrasalmidae from the Brazilian Amazon: Calpi dorthecium crescentis (Mizelle and Price, 1965) comb. n. (syn. Uroclei dus crescentis Mizelle and Prier, 1965), C. serrasalmus (Mizelle and P rice, 1965) comb. n. (syn. Cleidodiscus serrasalmus Mizelle and Price, 1965), and Calpidothecioides pygopristi sp. n. from Pygopristis denti culata; Odothecium raphidiophallum sp. n. from Catoprion mento; and No tothecioides llewellyni sp. n. from Myleus torquatus and M. rubipinnis . Four new genera are proposed: Calpidothecium is characterized by dac tylogyrids with a single vagina opening sinistrolaterally. 1 pair of e yes, overlapping gonads, a seminal vesicle representing a dextral loop of the vas deferens, and a distal rod of the accessory piece with ter minal branches; Calpidothecioides is characterized by species with a d ouble vagina (left branch opening sinistrolaterally, right branch loop ing right cecum and opening on the dorsomedial body surface), I pair o f eyes, overlapping gonads, a seminal vesicle comprising a dextral loo p of the vas deferens, and a simple termination of the distal rod of t he accessory piece; Odothecium is characterized by helminths with a si ngle vagina looping the left cecum and opening on the middorsal body s urface, 2 pairs of eyes, overlapping gonads, a seminal vesicle represe nting a dextral loop of the vas deferens, and a hook-shaped terminatio n of the distal rad of the accessory piece; Notothecioides is characte rized by species with the vagina looping the left cecum and opening on the middorsal body surface, 2 pairs of eyes, overlapping gonads, a si gmoid seminal vesicle, and a simple or hook-shaped termination of the distal rod of the accessory piece. Urocleidus orthus Mizelle and Price , 1965, is transferred to Calpidothecioides.