Dactylogyridae Bychowsky, 1933 Notozothecium janauachensis n. sp.

(Figs. 1–15)

Synonym: Notozothecium sp. (of Belmont­Jégu, 1996).

Type­host: Colossoma macropomum (Cuvier, 1818), Characidae, Serrasalminae .

Site: Gills.

Type­locality: Lago Janauacá — Rio Solimões, Amazonas, Brazil, 3°25'S, 60°17'W, 1994–1995.

Other records: Centro de Aqüicultura, Universidade Estadual Paulista, Jaboticabal, State of São Paulo, Brazil, 21°16'S, 48°19'W (1992).

Specimens deposited: Holotype, INPA 208; 5 paratypes, INPA 209a–e; 4 vouchers MZUSP 5934 a–d; 6 vouchers INPA 447 a–f; 7 vouchers CHIOC 36393 a–g.

Etymology: The specific name is derived from the type locality, Lago Janauacá.

Comparative measurements: Table 1.

from C. macropomum from natural habitats (Amazon basin) and experimental ponds.

Description: (based on 6 adult specimens). Body fusiform, greatest width near midlength. Tegument with annulations throughout trunk and peduncle. Cephalic lobes moderately developed. Posterior eyes larger than anterior eyes, slightly farther apart than anterior pair; eyes granules elongate; accessory granules absent or few in cephalic and anterior trunk regions. Pharynx spherical to subovate. Peduncle broad. Haptor subhexagonal. Ventral anchor larger than dorsal anchor, robust, roots well developed, heavily truncate superficial root, elongate and evenly curved shaft, short point. Dorsal anchor with elongated superficial root, slightly depressed deep root, slender shaft, short point. Ventral bar robust, with short digitiform anteromedial process, enlarged terminations. Dorsal bar delicate, broadly U­shaped, with enlarged terminations. Hook with truncate erect thumb, delicate point, expanded shank; proximal subunit of shank variable in length; FH loop extending to union of shank subunits Copulatory organ comprising a coil of about one ring; base cone­shaped with sclerotized margin; distal extremity with a long lateral extension pointed, feather­shaped. Articulation process of accessory piece short, wide, uniting with proximal end of distal rod; distal rod slightly sigmoid; broadly hook­shaped subterminal flap, serving as guide for male copulatory organ. Testis subovate; seminal vesicle sigmoid; prostatic reservoirs large, pyriform. Germarium subovate; vagina lightly sclerotized, a delicate tube opening on the dextrodorsal surface of the trunk; seminal receptacle pyriform; vitellaria limited to trunk, absent in regions of reproductive organs. Oviduct, ootype and uterus not observed.