Ligophorus hamzati, Hafidi & Diamanka & Rkhami & Pariselle, 2013

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 : 222-224

Ligophorus hamzati n. sp.

(Fig. 5)

TYPE MATERIAL. — Holotype MNHN HEL315 ; paratypes MNHN (9) HEL316, BMNH (10) 2012.12.17.4.

MATERIAL EXAMINED. — 30 specimens mounted in ammonium picrate-glycerol.

TYPE HOST. — Liza grandisquamis (Mugilidae) .

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

TYPE LOCALITY. — Grand Lahou Lagoon, Ivory Coast (5°08’11”N, 5°01’33”E).

ETYMOLOGY. — Hamzati is given for Hamzat, name of the son of the first author of this article.

FIG. 5. – Ligophorus hamzati n. sp.: morphological structures as in Fig. 1. Abbreviations: see Material & Methods. Scale bar: 30 µm.

DESCRIPTION

Flattened adult, 580 ± 33 (410-537) [30] long and 80 ± 10 (65-116) [30] wide at gonad level, pharynx: 26 (20-33) [28] larger diameter. Haptor well demarcated with 14 marginal hooks: 13 ± 0.9 (8-17) [360] long. Dorsal anchor with guard two time longer than shaft: a = 43 ± 4 (34-50) [60]; b = 34 ± 3 (28-39) [60]; c = 6 ± 0.7 (4-7) [60]; d = 13 ± 1.5 (9-16) [60]; e = 7 ± 0.8 (6-9) [60]. Dorsal bar V-shaped: 20 ± 2 (17-24) [30] long, 4 ± 0.7 (3-6) [30] wide and 7 ± 1.1 (5-10) [30] high. Ventral anchor: a = 42 ± 2 (36-45) [60]; b = 34 ± 2 (31-37) [60]; c = 7 ± 0.8 (5-10) [60]; d = 11 ± 1.3 (8-14) [60]; e = 7 ± 0.6 (6-9) [60]. Ventral bar, 39 ± 3 (32-47) [30] long and 9 ± 2 (6-13) [30] wide, with small antero-median protuberance and two lateral and symmetrical expansions: 10 ± 3 (4-18) [30] apart. MCO as copulatory tube: 92 ± 6 (81-100) [30] long, passes through a tubular accessory piece, 48 ± 7 (38-59) [30] long, with bifurcated distal extremity, each branches bifurcated also. Vagina: 51 ± 10 (21-67) [30] long.

REMARKS

This species is distinguished from all Ligophorus species by the shape of the accessory piece of the copulatory organ, which is bifurcated two times at its distal extremities.

DISCUSSION

The co-existence of fish hosts with a great difference in Ligophorus species richness is not exceptional. Euzet & Suriano (1977) observed only one species ( Lig. angustus Euzet & Suriano, 1977 ) from Chelon labrosus (Risso, 1827) in the Mediterranean Sea, whereas the other mullet species may be parasitized by at least two species. Six species were reported from Liza carinata by Dmitrieva et al. (2012) and from Liza subviridis by Soo and Lim (2012), and at least 14 species were reported from M. cephalus by Dmitrieva et al. (2012).

Similar differences in monogenean species richness were reported from cichlid hosts in West Africa by Pariselle et al. (2003). These authors drew a parallel between parasite species richness and host genetic diversity, which were both shaped by fluctuations of host populations through bottleneck or vicariant events. Therefore, in the case of Ligophorus from studied African mugilids, only the population of Liza bandialensis , which is endemic to a very limited area in Senegal, may have suffered numerous bottleneck events, leading to reductions in its size, and in turn to the loss of all its monogenean parasites. Among the three other widely distributed Liza species in Africa, Liza falcipinnis , which was infected by only one Ligophorus species , may have had a more stable history (and thus, a lower genetic and parasitic diversity) when compared to Liza grandisquamis , which was infected by three Ligophorus species and Liza dumerili , which according to Berrada Rkhami et al. (1993) was infected by over ten Ligophorus species.