Dactylogyrus nachtigalensis Fankoua, Bassock Bayiha & Rahmouni, 2022

Fankoua, Sévérin-Oscar, Bayiha, Etienne Didier Bassock, Nyom, Arnold Roger Bitja, Rahmouni, Imane, Nlôga, Alexandre Michel Njan & Bilong, Charles Félix Bilong, 2022, Three new Dactylogyrus species (Monogenea: Dactylogyridae) and redescription of one other, gill parasites of five Labeo spp. (Cypriniformes: Cyprinidae) from the Sanaga basin (Cameroon, Central Africa), Zoologia (e 21009) 39, pp. 1-12 : 4-5

Dactylogyrus nachtigalensis Fankoua, Bassock Bayiha & Rahmouni , sp. nov.

Fig. 4

http://zoobank.org/ 01715191-F0D4-44A7-9F41-8E1532573603

Type host. Labeo batesii Boulenger, 1911 .

Infection site. Gill lamellae.

Type locality. Nachtigal (04°20’50.1”N; 011°38’00.3”E).

Other localities. Ndokoa (04°23’56.64”N; 011°44’14.52”E) , National Park of Mpem and Djim (5° 6’37.23”N; 11°33’28.91”E) , Assamba (04°24’33”N; 011°49’47.34”E) .

Prevalence. 90%.

Mean intensity. 5.1.

Material studied. 12 whole mounted specimens in GAP.

Type specimens. Holotype RMCA _VERMES_43364 , Paratype RMCA _VERMES_43365 , Paratype RMCA _VERMES_43366 , Paratype RMCA _VERMES_43367 , RMCA_VERMES_4338 and RMCA_VERMES_43369.

Etymology. Epithet nachtigalensis refers to the type locality (Nachtigal).

Description. The anatomy is that of the Dactylogyrus . Body length 339.9 (194.4–402.9; n = 12); width 70.7 (42.5–86.8; n = 12) at the level of ovary. Haptor not really separated from the rest of the body by a constriction; cephalic glands present, two pairs of eye-spots of variable sizes, anterior to pharynx. Dorsal anchor with arched point, guard distinctively longer than shaft, arched narrow handle. Dorsal bar (DB) slightly curved at its median part. Ventral bar (VB) crescent moon-shaped, much smaller than dorsal bar. Presence of seven pairs of hooks with same morphology and size except pair VI smaller than the others; all hooks kept their larval form (oncomiracidia). One pair of needles (N) located near hooks of pair V. Male copulatory organ (MCO): tubular J-shaped penis begins with a basal bulb, runs alongside the accessory piece. Accessory piece straight bar, wrapped around the basal bulb, ends in two branches like in D. sanagaensis sp. nov., one branch straight and sharp ended, the other one longer, thinner at its distal part, folded back at first third, reaches the sharp end then folded back again. Base of accessory piece (AP b) shorter than in D. sanagaensis sp. nov. Vagina short with large aperture, distal extremity with sclerotised plate.

The measurements of haptoral and reproductive sclerites are given in Table 1 .

Remarks. Dactylogyrus nachtigalensis sp. nov. is close to D. sanagaensis sp. nov. by the morphology of its haptor and MCO, but differs from it by (i) the length of the penis: 52.1–65.6 µm vs 42.7–47.1 µm, (ii) the morphology of the dorsal bar, straight in both species, but slightly curved in the median part in D. nachtigalensis sp. nov., (iii) the total length of male copulatory organ: 11.7–14.8 µm vs 17.8–30.4 µm in D. sanagaensis sp. nov., the morphology and size of the vagina, not flame shaped and 5.6–9.1 µm vs flame shaped and 7.4–17.2 µm in D. sanagaensis sp. nov. Dactylogyrus nachtigalensis is also close to D. dembae (syn: D. cf. labeous ) from Labeo coubie by the morphology of the haptor and male copulatory organ. The main differences are the length of penis 42.7–47.1 µm and of the MCO 11.7–14.8 µm vs 27–34 µm and 26–30µm in D. dembae . Dactylogyrus nachtigalensis sp. nov. also presents the typically morphology of ‘pseudanchoratus-like group’.

Figures

Figure 4. Drawing of sclerotized parts of Dactylogyrus nachtigalensis sp. nov.: (DA) dorsal anchor, (DB) Dorsal bar, (VB) ventral bar, (Pe) penis, (AP) accessory piece, (Vg) vagina, (N) needle. Scale bar: 20 Μm.