Diversity of Quadriacanthus (Monogenea: Dactylogyridae) in the Upper Congo Basin: new geographical records and description of five new species from the gills of Clarias ngamensis (Siluriformes: Clariidae) Author Kasembele, Gyrhaiss K. Unité de Recherche en Biodiversité et Exploitation durable des Zones Humides, Faculté des Sciences Author Vanhove, Maarten P. M. Department of Biology, Royal Museum for Central Africa. Leuvensesteenweg 13, BE- 3080 Tervuren, Belgium. & Research Group Zoology: Biodiversity & Toxicology, Centre for Environmental Sciences, Hasselt University. & Laboratory of Biodiversity and Evolutionary Genomics, Department of Biology, University of Leuven. & Capacities for Biodiversity and Sustainable Development, Operational Directorate Natural Environment, Author Manda, Auguste Chocha Unité de Recherche en Biodiversité et Exploitation durable des Zones Humides, Faculté des Sciences Author Jorissen, Michiel W. P. Department of Biology, Royal Museum for Central Africa. Leuvensesteenweg 13, BE- 3080 Tervuren, Belgium. & Research Group Zoology: Biodiversity & Toxicology, Centre for Environmental Sciences, Hasselt University. Author Luus-Powell, Wilmien J. DSI-NRF SARChI Chair in Ecosystem Health, Department of Biodiversity, University of Limpopo. Sovenga, Author Smit, Willem J. DSI-NRF SARChI Chair in Ecosystem Health, Department of Biodiversity, University of Limpopo. Sovenga, Author Bilong Bilong, Charles F. Laboratory of Parasitology and Ecology, Faculty of Sciences, University of Yaoundé 1. Cameroon. jrskasembele@gmail.com Author Bahanak, Dieu-Ne-Dort Institute of Agricultural Research-Minko multipurpose research Station. PO Box 167, Meyomessala, Cameroon. Corresponding author: Gyrhaiss Kapepula Kasembele (jrskasembele @ gmail. com) text Zoologia 2024 e 23090 2024-11-29 41 1 19 https://doi.org/10.1590/s1984-4689.v41.e23090 journal article 10.1590/S1984-4689.v41.e23090 1984-4689 14700789 Quadriacanthus domatanai Kasembele, Bahanak & Vanhove , sp. nov. https://zoobank.org/ 7F290D48-6835-4D0F-9E05-7BE97306AFF2 Type-host and locality: C. ngamensis ; DR Congo , Haut-Katanga , Lubanda village , Lake Lubanda 11°04’S , 27°55’E , November 2021 , G.K. Kasembele leg. Other locality: Luapula River Prevalence: P = 13.3% (Lake Lubanda); P = 20% (Luapula River). Mean intensity: Lake Lubanda: 1.5 ± 1.6; Luapula River: 2 ± 2.1 MCO Figure 5. Sclerotized parts of the genitals and haptor of Quadriacanthus amakaliae sp. nov. With the male copulatory organ (MCO), accessory piece (AP), vagina (Vg), ventral bar (VB), ventral anchor (VA), ventral cuneus (Vcn), dorsal bar (DB), dorsal anchor (DA), dorsal cuneus (Dcn), (I-VII) hooks. Scale bar: 20 µm. Type-material: The holotype HU n° 892 and seven paratypes HU #900; 901; 928–930; 1001; 1004 are deposited in the collection of the Research Group Zoology: Biodiversity & Toxicology , at Hasselt University ( Diepenbeek , Belgium ) . Etymology: This species is named in honour to Doma Tana Anicet, MSc, of the Unité de Recherche en Biodiversité et Exploitation durable des Zones Humides, Faculté des Sciences agronomiques, Université de Lubumbashi, DR Congo , for his valuable and kind assistance during our field campaigns. Description: MCO long, wide at proximal end and tapered at distal extremity. Accessory piece long, robust and thickening in its median part, and with bulge on the external and internal faces and ending in hook. Vagina not observed. Dorsal anchor without shaft nor guard, but with curved blade ending with short point. Dorsal bar with rectangular centre, one small median process posteriorly directed and two lateral expansions. Dorsal cuneus triangular. Ventral anchor without shaft nor guard, with thin and regularly curved blade. Ventral bar V-shaped with two lateral branches. Y-shaped ventral cuneus. Seven pairs of hooks: pairs IV, III, I (decreasing size) larger than pairs II, V, VI and VII, latter pairs almost equal in length ( Fig. 7 ). Remarks: This species is similar to Q. ndoubai Bahanak, Pariselle & Bilong Bilong, 2017 and Q. macrocirrus N’Douba, Lambert & Euzet, 1999 , described respectively on H. longifilis and H. isopterus , considering the morphology of their haptoral structures (the robust shape of the ventral and dorsal bars). However, they can be distinguished by the shape of the MCO (large and slightly curved vs large and straight in Q. macrocirrus ), and the shape of the AP (large, robust, thickening in its median part and ending in a point vs simple, long and tapered in Q. macrocirrus , and ending in a fork in Q. ndoubai ). Figure 6. Sclerotized parts of the genitals and haptor of Quadriacanthus halajiani sp. nov. With the male copulatory organ (MCO), accessory piece (AP), ventral bar (VB), ventral anchor (VA), ventral cuneus (Vcn), dorsal bar (DB), dorsal anchor (DA), dorsal cuneus (Dcn), (I-VII) hooks. Scale bar: 20 µm. Quadriacanthus lubandaensis Kasembele , Bahanak & Vanhove, sp. nov. https://zoobank.org/ F914590C-3987-466B-8FB0-470B7C280F7D Type-host and locality: Clarias ngamensis ; DR Congo , Haut-Katanga , Lubanda village , Lake Lubanda 11°04’S , 27°55’E , November 2021 , G.K. Kasembele leg. Other locality: Luapula River. Prevalence: P = 26.7% (Lake Lubanda); P = 33.3% (Luapula River). Mean intensity: Lake Lubanda: 1 ± 0.8; Luapula River: 1.8 ± 1.4. Type-material: The holotype HU #954 and 12 paratypes HU #893; 895; 904; 905; 914; 920; 934; 956; 972; 978; 990; 991 are deposited in the collection of the Research Group Zoology: Biodiversity & Toxicology, at Hasselt University (Diepenbeek, Belgium ). Etymology: The epithet lubandaensis refers to the type locality. Description: MCO simple and straight tube. Accessory piece articulating with copulatory tube, with hook-like ending. Vagina not observed. Dorsal anchor without shaft nor guard, with broad base, curved shaft, medium point lenght. Dorsal bar with rectangular centre, medium median process posteriorly directed and two lateral expansions. Dorsal cuneus triangular. Ventral anchor without shaft nor guard, with regular curved blade. Ventral bar V-shaped with two lateral branches. Y-shaped ventral cuneus. Seven pairs of hooks: pairs IV, I, III (decreasing size) larger than pairs II, V, VI and VII. Four latter pairs are almost equal in length ( Fig. 8 ). Figure 7. Sclerotized parts of the genitals and haptor of Quadriacanthus domatanai sp. nov. With the male copulatory organ (MCO), accessory piece (AP), ventral bar (VB), ventral anchor (VA), ventral cuneus (Vcn), dorsal bar (DB), dorsal anchor (DA), dorsal cuneus (Dcn), (I-VII) hooks. Scale bar: 20 µm. Remarks: This species is comparable to Q. fornicatus Francová & Řehulková, 2017 , described from C. gariepinus from Sudan ( Francová et al. 2017 ) by the morphology of the ventral bar, the ventral anchors, the ventral and dorsal cunei, and the MCO (straight tube, base simple). However, these species are different in the morphology of the dorsal anchors (with long points in Q. fornicatus 12–13 vs 5–11 in Q. lubandaensis sp. nov. ), the MCO (with a thickened wall) and the AP (with a well developed hook at the distal end) in Q. fornicatus vs the MCO (with thin margin) and the AP (hook-like, not well developed, less curved) in Q. lubandaensis sp. nov. Quadriacanthus curvicirrus Kasembele, Bahanak & Vanhove, sp. nov. https://zoobank.org/ 8DCFEA56-C3A9-426F-94E4-B620B0DE2F5B Type-host and locality: Clarias ngamensis ; DR Congo , Haut-Katanga , Kasenga , Luapula River 10°24’S , 28°37’E , November 2021 , G.K. Kasembele leg. Prevalence: P = 66.7% (Luapula River). Mean intensity: Luapula River: 6.3 ± 5.8. Type-material: The holotype HU n° 984 and 62 paratypes HU n° 910–913; 915–917; 921; 922; 924–927; 931–933; 935–937; 941–949; 952; 953; 955; 957 –959; 961–966; 968–971; 974–976; 979–984; 989; 993–998; 1000; 1002; 1003 are deposited in the collection of the Research Group Zoology: Biodiversity & Toxicology , at Hasselt University ( Diepenbeek , Belgium ) . Etymology: the epithet curvicirrus refers to the curved form of the male copulatory tube. AP Figure 8. Sclerotized parts of the genitals and haptor of Quadriacanthus lubandaensis sp. nov. With the male copulatory organ (MCO), accessory piece (AP), ventral bar (VB), ventral anchor (VA), ventral cuneus (Vcn), dorsal bar (DB), dorsal anchor (DA), dorsal cuneus (Dcn), (I-VII) hooks. Scale bar: 20 µm. Description: Tubular MCO, with simple base, curved at its distal end, hook shaped, with a swollen portion just before the curvy part. Accessory piece massive with outgrowths posteriorly and anteriorly, with the distal part smaller, ending in a point. Dorsal anchor without shaft nor guard, with broad base, shaft sharply bent, short point. Dorsal bar with rectangular centre, broad and long median process posteriorly directed and two lateral expansions. Dorsal cuneus triangular. Ventral anchor without shaft nor guard, with narrow base and curved blade. Ventral bar V-shaped with two lateral branches. Ventral cuneus triangular. Seven pairs of hooks: pairs IV larger than pairs I, II, III, V, VI and VII. Four latter pairs are almost equal in length ( Fig. 9 ). Vagina not observed. Remarks: Quadriacanthus curvicirrus sp. nov. is similar to Q. barombiensis in the shape of the ventral and dorsal anchors and cunei. They can be distinguished by the median process of the dorsal bar without filaments at its end in Q. curvicirrus sp. nov. vs with two filaments in Q. barombiensis ; with respective median process length h= (41.1–50.2) vs (27–32). The MCO of Q. curvicirrus sp. nov. is characteristic, tubular, curved at its distal end with a simple base and the accessory piece massive with outgrowths posteriorly and anteriorly directed. This differs from the situation in Q. barombiensis with a tubular straight MCO and a simple, slightly S-shaped accessory piece, ending in one small point.