Vancleaveus klasseni, Soares & Neto & Domingues, 2018

Soares, Geusivam Barbosa, Neto, João Flor dos Santos & Domingues, Marcus Vinicius, 2018, Dactylogyrids (Platyhelminthes: Monogenoidea) from the gills of Hassar gabiru and Hassar orestis (Siluriformes: Doradidae) from the Xingu Basin, Brazil, Zoologia (e 23917) 35, pp. 1-19 : 12-14

Vancleaveus klasseni sp. nov.

http://zoobank.org/ BC5808A4-0404-43A0-872D-234B15A188CF

Figs 30–36

Type host. Hassar orestis (Steindachner, 1875) , Doradidae

Site of infection. Gill filaments.

Type locality. Xingu River, Belo Monte Community, municipality of Vitória of Xingu , Pará (03°05’52.5”S, 51°43’18.0”W; 02°47’27.1”S, 51°59’50.0”W) .

Prevalence. 50% of 24 hosts examined

Mean intensity. 2.3 parasites per infected host.

Mean abundance. 1.6 parasites per host.

Other records. Hassar gabiru (Prevalence: 30% of 15 hosts; Mean intensity: 2; Mean abundance: 0.6), Bacajá River, municipality of Altamira, Pará (03°33’47.1”S, 51°36’50.3”W); Hassar gabiru (Prevalence: 16% of 12 hosts; Mean intensity: 2; Mean abundance: 0.3), Ilha Grande, Xingu River, municipality of Altamira, Pará (03°35’50.2”S, 52°21’22.5”W).

Specimens deposited. Holotype CHIOC 39058 a, and 9 paratypes, CHIOC 39058 b–h, INPA 778 , MPEG 0143 ; 4 vouchers, CHIOC 39059–39060 , INPA 779 , MPEG 0144 .

Description (based on 10 type specimens, 3 mounted in Hoyer, 7 stained with Gomori’s trichrome): Body fusiform, total length including haptor 315 (215–517; n = 9) long, 89 (65–122; n = 9) wide, at level of germarium. Tegument smooth ( Fig. 30). Cephalic margin rounded, cephalic lobes inconspicuous; 5 or 6 bilateral pairs of head organs with rod-shaped secretion; cephalic glands unicellular, posterolateral to pharynx. Eyes, pigment granules (eye-spots), absent. Mouth subterminal; pharynx muscular, spherical, 33 (25–36; n = 8) long, 17 (15–20; n = 8) wide; esophagus short; two intestinal ceca, confluent posteriorly, lacking diverticula. Haptor hexagonal 71(52–90; n = 9) wide. Anchors similar. Ventral anchor, divergent roots; superficial root triangular, well developed, with conspicuous fold; deep root developed; slightly curved shaft and point, forming angle of approximately 65°, point extending just past level of tip of superficial root, outer 24 (21–28; n = 6) long, inner 28 (27–32; n = 6) long, base 10 (8–12; n = 6) ( Fig. 35). Dorsal anchor, divergent roots; superficial root subtriangular, with conspicuous fold; deep root developed; slightly curved shaft and point, forming angle of approximately 80°, point extending just past level of tip of superficial root, outer 24 (18–27; n = 4) long, inner 29 (29–30; n = 4) long, base 10 (10–11; n = 4) ( Fig. 36). Ventral bar ( Fig. 33) 35 (27–45; n = 10) long, 4 (3–5; n = 10) wide, broadly U-shaped with inflated ends, posteromedial projection developed. Dorsal bar ( Fig. 34) 29 (21–38; n = 10) long, 3 (2–3; n = 10) wide, V-shaped, with slightly inflated ends. Hooks similar ( Fig. 32), 21 (20–25; n = 10) long, with upright slightly acute thumb; slightly curved shaft, short; dilated shank; filamentous hook about ½ shank length. Genital pore opening midventral, anterior to copulatory complex. Testis post-germarial, dorsal to germarium, ovoid 25 (20–30; n = 2) long, 19 (19–20; n = 2) wide. Vas deferens looping left of intestinal cecum; seminal vesicle a dilatation of vas deferens; transversally elongated prostatic reservoir. Copulatory complex comprising MCO, accessory piece ( Fig. 31). MCO a coiled sclerotized tube, 96 (88–106; n = 6) long, with 2 ½ counterclockwise rings, with tapered distal region; base a cap with sclerotized margin. Accessory piece 16 (15–18; n = 5) long, elongated, non-articulated with MCO, with tapered proximal region, distal end with small gutter guarding termination of MCO. Germarium 45 (29–62; n = 2) long, 18 (16–20; n = 2) wide, elongate. Eggs, Mehlis’ gland, ootype and uterus not observed. Vagina slightly sclerotized, ventral, opening sinistrally; vaginal canal slightly sclerotized, distal region with a bulb serving the connection to the seminal receptacle; seminal receptacle, pyriform. Vitelline follicles dense, coextensive with ceca.

Comparative measurements. Table 7.

Etymology. The species is dedicated to Dr. Gregory J. Klassen in recognition for his work on systematics of monogenoids.

Remarks. Vancleaveus klasseni sp. nov. differs from its congeners by (1) possessing anchors with divergent roots; superficial root triangular to subtriangular, well developed, with conspicuous fold; deep root developed; curved shaft and point; (2) MCO a coiled sclerotized tube with 2 ½ rings, base with sclerotized margin; and (3) accessory piece with small gutter in the distal.