Bagrobdella vanhovei Mushagalusa Mulega & Pariselle, 2022

Mulega, Archimède Mushagalusa, Bukinga, Fidel Muterezi, Akoumba, John Francis, Mulungula, Pascal Masilya & Pariselle, Antoine, 2022, Monogeneans from Catfishes in Lake Tanganyika. I: Two new species of Bagrobdella (Dactylogyridae) from Auchenoglanis occidentalis (Siluriformes: Claroteidae), Zoologia (e 22016) 39, pp. 1-13 : 3-5

Bagrobdella vanhovei Mushagalusa Mulega & Pariselle , sp. nov.

Fig. 8

https://zoobank.org/ A7869408-CD17-4AB3-BFDC-9362C5DA9F13

Type-host. Auchenoglanis occidentalis (Valenciennes, 1840) .

Site of infection. Gills.

Type locality. Mouth of Mutambala River (29°04.4042’E, 04°16.4598’S) and off the Orthodox church of Uvira (29°08’32.6”E, 03°23’42.0”S) ( DRC) ( Fig. 1 ) .

Studied material. 78 specimens mounted in Hoyer’s medium.

Number of hosts examined. 11.

Prevalence. 6/11 = 54%.

Mean intensity. 318/6 = 53.

Abundance. 318/11 = 28.9.

Deposited material. Holotype deposited at the Royal Museum for Central Africa , Tervuren , Belgium ( RMCA _VERMES_43660), paratypes deposited at the MRAC (number RMCA _ VERMES_43661), the MnHn , Paris , France ( MNHN HEL1824 ) and the Iziko South African Museum , Cape Town , Republic of South Africa ( SAMC) ( SAMC-A094638 ).

Description. Length 681 (522–965; 72); greatest width 200 (140–273; 72); pharynx 71 (49–97; 61); Dorsal anchor: a = 82 (65–94; 78), b = 66 (53–76; 78), c = 9 (3–17; 78), d = 21 (13–30; 78), e = 19 (13–22; 78), no visible filaments. Dorsal bar x = 87 (62–112; 72), w = 15 (9–23; 71), median projection posteriorly oriented: Y = 59 (33–82; 61). Ventral anchor slightly drilled at the blade beginning: a = 65 (38–74; 78), b = 71 (60–79; 78), c = 11 (5–16; 78), d = 18 (13–24; 78), e = 6 (3–9, 77), no visible filaments. Ventral bar x = 112 (76–146; 75), w = 16 (9–27; 74) extends in the form of an outgrowth, BL = 11 (5–20; 60), Bl = 6 (3–13; 60), median projection posteriorly orientated, cross-shaped, Cx = 72 (58–91; 77), Cy = 20 (14–29, 76). At median projection posterior extremity is attached another sclerotized piece trapeze-shaped. Fourteen hooks arranged in seven symmetrical pairs of different sizes: I (medio-ventral) the largest and longest: 52 (34–64; 77), II (medio-ventral) the smallest hooks: 17 (13–20; 69), III and IV (latero-dorsal and almost identical in size): 39 (27–48; 74) V to VII (latero-ventral and almost identical in size) 25 (17–35; 72). A medium-ventral trapezoidal plate, slightly sclerotized, is located between hooks I, L: 37 (28–50; 15), l: 28 (22–35; 16). Male copulatory organ (MCO): 61 (51–67; 71) with a well-developed basal bulb: AL = 15 (10–22; 41), Al = 10 (3–20; 41), followed by a thick-walled tube of constant diameter, folded at 30° at the middle, distal half surrounded by a membrane; at the distal extremity of the tube (level of opening) a portion of the wall formed a triangular part tapering at its end, length a quarter of that of the tube. Lidded eggs 93 (83–110; 12) are ovoid, at the pole opposite to the operculum is a filament finished by a small disc, exactly as described by Euzet and Le Brun (1990) in the diagnose of Bagrobdella .

Etymology. The species is named after Professor Dr. Maarten P.M. Vanhove (University of Hasselt, Belgium), who is a specialist in monogeneans of cichlids from Lake Tanganyika.

Note. The authors of the new taxa are different from the authors of this paper: Article 50.1 and Recommendation 50A of the International Code of Zoological Nomenclature.

Remarks. The new species was placed in Bagrobdella due to the presence of a haptor with dorsal, ventral anchor/bar complexes, 7 pairs of hooks with ancyrocephaline distribution, pairs 1, 3–7 with shanks comprised of 2 subunits, proximal subunit expended, pair 2 with shank of 1 subunit. Ventral bar straight, with long anterior projection associated with lightly sclerotized skirt, dorsal bar straight, with posterior shield-like projection, which are characteristics of the genus ( Kritsky and Kulo 1999). Bagrobdella vanhovei sp. nov. is similar to B. auchenoglanii , B. fraudulenta , B. parauchenoglanii and B. anthopenis by (1) having a trapezoidal-shaped (former visible in 15 of the 78 studied specimens) piece associated with the median projection of the ventral bar ( Figs 9–14 ), (2) having seven pairs of hooks of different sizes. Its dorsal anchors have a long point, while its ventral anchors have a very short one, like in Bagrobdella auchenoglanii and B.fraudulenta ( B. parauchenoglanii and B. anthopenis having points of the same size for both ventral and dorsal anchors). Bagrobdella vanhovei sp. nov is easily distinguished from all species already described by the morphology of its MCO which is unique, being not spirally coiled – when all other species have a coiled MCO, which was a genus character ( Kritsky and Kulo 1999), and more, the MCO of B. vanhovei has a sub-terminal opening (at three quarter of the total length), when for all other species the opening is terminal ( Figs 15–20 ).

Bagrobdella vanhovei sp. nov has two small hard parts that have never been reported before in the description of Bagrobdella species. These are: 1) a structure in the shape of a button between the bar and ventral anchors ( Fig. 26 ), 2) a semi-circular structure toping the extremity of the ventral bar median projection ( Fig.25 ).

Figures

Figure 1. Sampling sites localities.

Figure 8. Bagrobdella vanhovei sp. nov. haptoral structure and MCO. Scale bar: 20 µm.

Figures 9–14. Haptors of the six species belonging to Bagrobdella: (9) Bagrobdella vanhovei sp. nov.; (10) Bagrobdella vansteenbergei sp. nov.; (11) Bagrobdella auchenoglanii; (12) Bagrobdella fraudulenta; (13) Bagrobdella anthopenis; (14)Bagrobdella parauchenoglanii (Akoumba et al 2017, Euzet and Le Brun 1990). Scale bars: 20 µm.

Figures 15–20. MCO of the six species belonging to Bagrobdella: (15) Bagrobdella vanhovei sp. nov.; (16) Bagrobdella vansteenbergei sp. nov.; (17) Bagrobdella auchenoglanii; (18) Bagrobdella fraudulenta; (19) Bagrobdella anthopenis; (20) Bagrobdella parauchenoglanii (Akoumba et al. 2017, Euzet and Le Brun 1990). Scale bar: 20 µm.

Figures 21–26. (21) Bagrobdella vanhovei sp. nov. microphotograph in toto; (22) Bagrobdella vansteenbergei sp. nov. microphotograph in toto; (23) Microphotograph of the trapezoidal plate in the haptor of Bagrobdella vanhovei; (24) Button like structure; (25) Semi-circular structure; (26) Egg (B. vanhovei sp. nov). Scale bars: 21 = 100 µm, 22 = 200 µm, 23, 24, 26 = 20 µm, 25 = 50 µm.