Ligophorus Euzet & Suriano, 1977

Hafidi, Fouzia El, Diamanka, Arfang, Rkhami, Ouafae Berrada & Pariselle, Antoine, 2013, New species of Ligophorus (Monogenea, Ancyrocephalidae), parasite of Liza spp. (Teleostei, Mugilidae) off the Northwestern African coast, Zoosystema 35 (2), pp. 215-225 : 218-220

Ligophorus Euzet & Suriano, 1977

TYPE SPECIES (BY ORIGINAL DESIGNATION). — Lig. vanbenedenii (Parona & Perugia, 1890) Euzet & Suriano, 1977 syn. Tetraonchus vanbenedenii Parona & Perrugia, 1890 ; Ancyrocephalus vanbenedenii (Parona & Perrugia, 1890) Johnston & Tiegs, 1922 ; Haplocleidus vanbenedenii (Parona & Perrugia, 1890) Palombi, 1949 ; Haliotrema vanbenedenii (Parona & Perrugia, 1890) Young, 1968 .

Ligophorus gabrioni n. sp. (Fig. 2)

TYPE MATERIAL. — Holotype: MNHN HEL313 ; paratypes: MNHN (10) HEL314, BMNH (10) 2012.12.17.1.

MATERIAL EXAMINED. — 26 specimens mounted in ammonium picrate-glycerol and five living specimens.

TYPE HOST. — Liza falcipinnis (Valenciennes, 1836) (Mugilidae) .

SITE OF INFECTION. — Gills, between secondary gill lamellae.

TYPE LOCALITY. — Off Dakar, Senegal (14°43’09”N, 17°25’48”W).

OTHER LOCALITIES. — Grand Lahou Lagoon, Ivory Coast (5°08’11”N, 5°01’33”E) and Lake Cayo, Congo (4°43’09”S, 12°00’46”E).

ETYMOLOGY. — The name gabrioni is given in honor of Pr Claude Gabrion, who supervised the early work on mugilid parasites from Western and Northern African coasts.

DESCRIPTION

Flattened adult, 542 (453-645) [26] in length and 123 (92-188) [26] in width at gonad level. Mouth sub-terminal followed by a muscular ovoid pharynx: 45 (40-53) [20] in larger diameter. Haptor, 117

FIG. 2. – Ligophorus gabrioni n. sp.: morphological structures as in Fig. 1. Abbreviations: see Material & Methods. Scale bar: 30 µm.

(93-153) [26] maximum width. Dorsal bar invert V-shaped, sometime U-shaped or nearly straight: 22 (20-27) [20] long, 7 (6-10) [20] wide and 8 (1-13) [20] high (variable following the shape of the bar: V, U or straight). Dorsal anchor, with curved blade, bent at right angle near the point; the point one quarter of the blade: a = 38 ± 1 (36-40) [52]; b = 29 ± 1 (27-30) [52]; c = 9 ± 0.6 (7-11) [52]; d = 14 ± 0.6 (12-15) [52]; e = 9 ± 0.6 (8-11) [52]. Ventral bar broad inverted V-shaped with small antero-median protuberance and two lateral and symmetrical expansions: 9 (7-10) [26] apart; ventral bar, 43 (40-44) [26] long and 10 (9-11) [26] wide at the middle. Ventral anchor similar in shape with dorsal, somewhat more robust: a = 37 ± 1 (35-39) [52]; b = 28 ± 1 (27-30) [52]; c = 8 ± 0.6 (7-10) [52]; d = 11 ± 0.5 (10-12) [52]; e = 9 ± 0.6 (7-11) [52]. 14 hooks, 13 ± 0.4 (11-14) [61] long, similar in shape and size (straight shaft, a short guard and a curved blade). MCO consists of small median cirrus and an accessory piece. Curved tubular cirrus, 54 (52- 55) [26] long, with an expanded base bipartite, passes through a tubular accessory piece distally expanded: 27 (26-29) [26] total length. No vagina observed, probably not sclerotised. Eggs not seen.

REMARKS

The comparison of Ligophorus gabrioni n. sp. with the 28 species of Ligophorus that were already described from Liza spp. [ Liza aurata (Risso, 1810) , Liza saliens (Risso, 1810) , Liza ramada (Risso, 1827) , Liza carinata (Valenciennes, 1836) , Liza subviridis (Valenciennes, 1836) , Liza vaigiensis (Quoy & Gaimard, 1825) , Liza abu (Heckel, 1843) , and Liza haematocheila (Temminck & Schlegel, 1845) (see Bychowsky 1949; Gussev 1955; Euzet & Suriano 1977; Euzet & Sanfilippo 1983; Dmitrieva & Gerasev 1996; Pan 1999; Miroshnichenko & Maltsev 2004; Sarabeev & Balbuena 2004; Balbuena et al. 2006; Dmitrieva et al. 2007; Dmitrieva et al. 2012; Soo& Lim 2012], shows that only Ligophorus navjotsodhii Soo & Lim, 2012 and Ligophorus parvicopulatrix Soo & Lim 2012 (both from Liza subviridis ) have no sclerotized vagina. Lig. parvicopulatrix differs from Lig. gabrioni n. sp. in the shape of the antero-median protuberance (raised median piece vs no raised) and the lack of the accessory piece of the penis (vs presence). Ligophorus navjotsodhii differs from Lig. gabrioni n. sp. in the shape of the accessory piece associated with the penis: ending in a sharp hook vs ending in a square expansion.

Significantly Lig. gabrioni n. sp. resembles Ligophorus parvicirrus Euzet & Sanfilippo, 1983 from Liza ramada in the shape of the accessory piece and the length of the penis (51 vs 52). These two species could be distinguished by the shape of the ventral transverse bar and, in particular, by the antero-median protuberance, which is massive in Lig. parvicirrus . In addition, the vagina in Lig. parvicirrus is sclerotized. Comparisons of Lig. gabrioni n. sp. with the 23 oth- er species of Ligophorus found on the gills of Mugil , Chelon , Valamugil and Crenimugil spp. show that only Ligophorus kedahensis Soo & Lim, 2012 and Ligophorus fenestrum Soo & Lim, 2012 have no sclerotised vaginas. Lig. fenestrum is unique in possessing anchors with fenestrations and Lig. kedahensis differs in the shape of its copulatory organ (no expansion at the extremity of the accessory piece) and the size of its anchors (blade very short in Lig. kedahensis ).