Steringovermes notacanthi, Bray, Rodney A., 2004

Bray, Rodney A., 2004, Steringovermes notacanthi n. gen., n. sp. (Digenea: Fellodistomidae) from the deep­sea spiny eel Notacanthus bonaparte (Notacanthiformes: Notacanthidae) from the north eastern Atlantic and a new host record for Olssonium turneri, Zootaxa 684, pp. 1-7 : 3-4

Steringovermes notacanthi n. sp. ( Figs. 1–2 )

Type­host: Notacanthus bonaparte Risso, 1840 , Notacanthiformes , Notacanthidae ; shortfin spiny eel.

Type­locality: Goban Spur, north eastern Atlantic (49°41'N, 11°53'W, depth 1,053– 1,077m, 23.iv.2001).

Site: Intestine.

Deposition of specimens: BMNH holotype 2004.7.14.47, paratypes 2004.7.14.31–46.

Prevalence: 3 of 3 (100%).

Intensity: 2–30 (12).

Etymology: Steringovermes , indicates a similarity to Steringophorus and Steringotrema ; notacanthi after the host genus.

Description. Based on 13 wholemounted specimens, including 2 fully ovigerous and one set of serial sections. Body oval to fusiform 1,728–2,897 × 612–1,303 (2,211 × 871); width 28–48 (39) % of body­length. Tegument smooth. Oral sucker oval, subterminal, 256–445 × 247–460 (342 × 342). Ventral sucker in mid­body, oval, 373–708 × 335–779 (549 × 516). Sucker­width ratio 1:1.4–1.8 (1.6); sucker­length ratio 1:1.4–1.7 (1.5). Forebody 735–1,126 (912), 38–46 (41) % of body­length. Prepharynx absent. Pharynx large, elongate oval, 218–350 × 140–277 (281 × 213). Oral sucker to pharynx width ratio 1:0.6– 0.7 (0.6). Oesophagus short, 35–91 (54) long. Intestinal bifurcation in mid­forebody, 168– 359 (286) from ventral sucker. Caeca reach mid­post­testicular region, terminate blindly 193–504 (339) from posterior extremity.

Testes 2, oval, entire or irregular, symmetrical, overlap posterior margin of ventral sucker, 182–441 × 170–310 (285 × 217), contiguous to 350 (51) apart, pre­ovarian. Posttesticular region 387–860 (629) long, 22–34 (28)% of body­length. Cirrus­sac large, oval, 317–618 × 151–348 (427 × 234). Seminal vesicle internal, bipartite, small; proximal part short, coiled tubular, wall thin, membranous; distal part oval, with wall 3.5–4 µm thick. Pars prostatica wide. Ejaculatory duct large, wide, pocketed. Prostatic cells more densely packed in anterior part of cirrus­sac at level of ejaculatory duct, with prostatic gland­cell ducts more distinct at level of pars prostatica. Genital atrium large. Genital pore anterosinistral to ventral sucker, overlies left caecum, post­bifurcal.

Ovary multilobate, postero­median to and contiguous with testes, 238–380 × 173–301 (305 × 224). 2–75 (39) posterior to ventral sucker. Post­ovarian region 267–677 (462) long, 15.2–28.1 (20.7)% of body­length. Mehlis' gland large, ventral to ovary. Laurer's canal opens dorsally at posterior level of ovary. Uterine seminal receptacle present. Uterus fills much of hind­body. Post­uterine region 100–290 (194) long, 4.6–13.2 (8.6)% of bodylength. Eggs small, tanned, operculate, 29–31 × 14–17 (30 × 16). Metraterm reaches from about mid­ventral sucker, narrow, with narrow gland­cell sheath, enters genital atrium through posterior wall. Vitellarium follicular, in lateral bands from level of intestinal bifurcation, 105–396 (261) anterior to ventral sucker to level of ovary, 357–771 (565) from posterior extremity. Post­vitelline region 20.7–30.4 (25.5)% of body­length.

vf sv t

ov Excretory pore terminal. Excretory vesicle V­shaped; arms reach level of oral sucker.

Figures

FIGURES 1 – 2. Steringovermes notacanthi n. gen., n. sp. 1. Ventral view of holotype, cirrus­sac and uterus in bold outline, bulk of excretory vesicle omitted. 2. Terminal genitalia reconstructed from sections. Abbreviations: ej, ejaculatory duct; mt, distal metraterm; ov, ovary; pp, pars prostatica; sv, seminal vesicle; t, testis; vf, vitelline follicle. Scale­bars: 1, 500 µ m; 2, 200 µ m.