Rhinoxenus guianensis, Domingues & Boeger, 2005

Domingues, Marcus V. & Boeger, Walter A., 2005, Neotropical Monogenoidea. 47. Phylogeny and coevolution of species of Rhinoxenus (Platyhelminthes, Monogenoidea, Dactylogyridae) and their Characiformes hosts (Teleostei, Ostariophysi) with description of four new species, Zoosystema 27 (3), pp. 441-467 : 453-454

Rhinoxenus guianensis n. sp.

( Fig. 3 G-M)

TYPE MATERIAL. — Holotype ( CHIOC 36305 ); paratypes ( CHIOC 36306 a-d; INPA 420 ; MNHN 154 HG-T1 196; USNPC 95222 ).

ETYMOLOGY. — The specific epithet refers to the type locality from which the species was collected.

TYPE HOST AND LOCALITY. — Nasal cavities of Curimata cyprinoides (Curimatidae) , Iracoubo, Degrad Forian, French Guiana, 8-10.X.1996.

DESCRIPTION

Eyes usually present, equidistant, members of posterior pair closer than those of anterior pair; eyes granules elongate. Ventral anchor delicate, 115 (106-125; n = 5) long, base 19 (15-22; n = 3) wide, roots inconspicuous; base with sclerotized cap articulated to ventral bar; straight shaft, point short, truncated, golf-club shaped. Dorsal anchor delicate, slender, 98 (95-100; n = 5) long; with blunt proximal, distal ends, slightly sinuous shaft; each end with conspicuous sclerotized cap. Ventral bar 35 (34-38; n = 5) long. Hook pair 2 21 (20-23; n = 4) long, erect thumb, shaft, point evenly curved, proximal 2/3 of shank inflation; FH loop extending to near beginning of shank dilation. Hook pairs 1, 3-7 22 (20-24; n = 3) long, elongate, erect thumb, lightly curved shaft, short point, proximal 2/3 of shank inflated; FH loop extending to near beginning of shank dilation. Male copulatory organ a coiled tube with approximately 1.5 rings, 15 (14-17; n = 4) in diameter. Gonads, ootype, uterus, seminal receptacle not observed. Vagina sclerotized; with a subterminal loop, distally expanded; vestibule sclerotized, cup-shaped. Eggs not observed.

REMARKS

All specimens of Rhinoxenus guianensis n. sp. were mounted in Hoyer’s medium. Measurements and description of internal organs, therefore, are limited. The new species differs from all other congeneric species by possessing ventral anchors with straight shafts, short, truncated, club-shaped points and dorsal anchors with distal portions truncated and curved.

Figures

FIG. 3. — Sclerotized structures in Rhinoxenus; A-F, R. curimbatae n. sp.; A, male copulatory organ (MCO); B, vagina; C, ventral anchor; D, dorsal anchor; E, hook; F, ventral bar; G-M, R. guianensis n. sp.; G, male copulatory organ (MCO); H, vagina; I, hook from pair 2; J, hook from pairs 1, 3-7; K, ventral bar; L, ventral anchor; M, dorsal anchor. Scale bars: A, B, 20 μm; C, D, F, 30 μm; E, I, J, 15 μm; G, H, 10 μm; K-M, 50 μm.