Onchobdella ximenae Jorissen, Pariselle

Jorissen, Michiel W. P., Pariselle, Antoine, Huyse, Tine, Vreven, Emmanuel J., Snoeks, Jos, Decru, Eva, Kusters, Thomas, Lunkayilakio, Soleil Wamuini, Bukinga, Fidel Muterezi, Artois, Tom & Vanhove, Maarten P. M., 2018, Six new dactylogyrid species (Platyhelminthes, Monogenea) from the gills of cichlids (Teleostei, Cichliformes) from the Lower Congo Basin, Parasite (Paris, France) 25 (64), pp. 1-21 : 16-17

Onchobdella ximenae Jorissen, Pariselle ,

Kusters & Vanhove n. sp.

urn:lsid:zoobank.org:act:826D2ABF-DB22-459B-8006-3BC12CEB8A6A

Type host: Hemichromis elongatus (Guichenot, 1861) .

Other hosts: H. stellifer Loiselle, 1979 .

Infection site: Gills.

Type locality: Pond Near Kila Kindinga 5° 290700 S 14° 5303.800 E.

Other localities: Mvuazi River on H. elongatus 5° 190 S; 15° 70 E; Mbola River near Tshianya village on H. stellifer 05° 52009.800 S 12° 39052.600 E.

Material: Three whole-mounted specimens in Hoyer’s medium, including the holotype and 13 in Malmberg’s solution .

Holotype: M. T. 38311.

Paratypes: M. T. 38319–20, 38324–25, 38327–28, 38334 NHMUK 2018.1 .31.2 and 2018.1.31.4, KN10049 https://laji.fi/en/view?uri=luomus:KN.10049 and 10052 https://laji.fi/en/view?uri=luomus:KN.10052, SAMC-372 A090065, A090067 .

Symbiotype: RMCA _Vert_2015.030.P.0020.

Paratype host vouchers: RMCA _Vert_2015.030.P.0019, RMCA _Vert_2015.030.P.0021, RMCA _Vert_2015.030.P.0022, AB53952197 .

Etymology: The species epithet is a homage to Ximena Sariñana Rivera, a Mexican singer and is a noun (name) in the genitive case.

Authorship: Note that the authors of the new taxon are different from the authors of this paper; Article 50.1 and Recommendation 50A of International Code of Zoological Nomenclature [13].

Description ( Table 5 , Figs. 8e–8f , 11 )

Dorsal anchors large (a = 51 µm) and orientated distal-laterally. Shaft undeveloped and bulbous (c = 2 µm). Guard with rounded edges. Point long with sudden and well-marked thickening on the interior side of the curve. Ventral anchors (f = 11 µm), with T-shaped base with rounded edges and a short, curved point. Dorsal bar slightly bent where both arms meet. Both arms make a 90° turn distally and thicken slightly. Distal tip of each arm bulbously thickened. Two ventral bars, thin, near straight. Six pairs of small hooks of same size. MCO consists of a basal bulb with a long, tubular penis (Pe = 66 µm), which makes one large loop of almost 360° along its course. A rounded, irregularly-shaped heel engulfs the basal bulb, except where the penis transitions into the basal bulb. Accessory piece consists of two rib-like structures that form an ellipsoid (resembling a windsurf wishbone), through which the penis passes. Both rib-like structures come together proximally, where they form a small bulge and distally, where their connection is smooth. At the distal end of the penis a leaf-like, smooth-edged plate is present, and is orientated perpendicular to the ellipsoid. Vagina, small, with two 90° curves, tubular (L = 33 µm).

Remarks

Onchobdella ximenae n. sp. resembles O. voltensis Paperna, 1968 , described from Lake Volta, Ghana from H. fasciatus and H. bimaculatus . Both O. ximenae n. sp. and O. voltensis have ventral bars with solid distal ends instead of filamentous ends, such as are seen in all other congeners. Furthermore, both species have an accessory piece that forms an ellipsoid, a penis that passes through it and a smooth, leaf-like plate at the distal end of the accessory piece. The differences between these species are that the dorsal anchors in O. ximenae n. sp. are 10–40 µm smaller (see Table 5 ) and have an undeveloped shaft. The ventral anchors have a T-shaped base, contrary to the ones in O. voltensis , which have a base that is orientated proximally and not laterally. The penis of O. voltensis is J-shaped, whilst in O. ximenae n. sp. it almost makes a loop and is 16–36 µm longer (see Table 5 ). Also, the leaf-shaped plate is orientated perpendicularly on the ellipsoid, while in O. voltensis it follows the orientation of the ellipsoid. Lastly, O. voltensis does not have a sclerotized vagina.

Figures

Figure 8. DIC micrographs of (a–b) Cichlidogyrus kmentovae n. sp. from Hemichromis stellifer: haptor (a), MCO (b); of (c–d) Cichlidogyrus omari n. sp. from Tylochromis praecox: haptor of holotype (c), MCO of holotype (d); compound micrographs of (e–f) Onchobdella ximenae n. sp. from Hemichromis elongatus: haptor (e), MCO (f). Scale bar 20 µm, except for (e) 50 µm.

Figure 11. Haptoral and genital hard parts of Onchobdella ximenae n. sp. from Hemichromis elongatus. Accessory piece of the MCO in grey, to highlight the plate-like structure of the accessory piece. I-VI, hooks; AP, accessory piece; DA, dorsal anchors; DB, dorsal transverse bar; MCO, male copulatory organ; Pe, penis; VA, ventral anchors; VB, ventral transverse bars; Vg, vagina. Scale bar: 20 µm, scale bar of the MCO 10 µm.