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Over the past 80 years, tilapia have been translocated globally for aquaculture; active production is recorded in >124 countries. Of 7 million tonnes of tilapia produced in aquaculture, 79% is from 79 countries outside the natural range of tilapia. Capture fisheries account for a further 723,627 tonnes of tilapia, and >47% of this is landed from established invasive populations outside Africa. Tilapias host a rich fauna of parasites, many of which have been translocated with their hosts. This review summarises >2500 host-parasite records from 73+ countries and >820 recorded tilapia translocations (provided in the supplementary materials). This work focuses on the notable pathogens that threaten the health of cultured populations of tilapia, providing a description of their pathology and includes species that also have substantial impacts on wild tilapia populations, where relevant. For each major parasite taxonomic group, we highlight which parasites have been translocated or have been acquired from the new environments into which tilapia have been introduced, together with remarks on standard treatment approaches and research on them and their management and control. Regarding the theme 'Tilapia health: quo vadis?', Africa has enormous potential for aquaculture growth, but substantial knowledge gaps about tilapia parasites in many African states remain, which creates associated production and biosecurity risks. For each parasitic group, therefore, the risks of parasite translocation to new regions as tilapia aquaculture industries expand are highlighted. Norwegian Agency for Development Cooperation (Norad), Grant/Award Numbers: GCP/GLO/352/NOR, GCP/GLO/979/NOR; This study was supported by two FAO projects, namely, GCP/GLO/ 979/NOR: Improving Biosecurity Governance and Legal Framework for Efficient and Sustainable Aquaculture Production and GCP/GLO/ 352/NOR: Responsible use of fisheries and aquaculture resources for sustainable development, both funded by the Norwegian Agency for Development Cooperation (Norad). We also acknowledge the support from Regular Programme funds under FAO's strategic framework on better production and three relevant programme priority areas, that is Blue Transformation, One Health and Safe Food. The authors gratefully acknowledge the following funding agencies: Annemarie Avenant-Oldewage would like to thank the University of Johannesburg, Faculty, and the Central Research Committee Funding in support of this work. Adriana García-Vásquez and Miguel Rubio-Godoy gratefully acknowledge INECOL Institutional Funds supporting their participation in this study. Roman Kuchta was supported by the Czech Science Foundation (grant no. 19-28399X). Jesús S. Hernández-Orts benefited from a postdoctoral fellowship from the Consejo Nacional de Ciencia y Tecnología, CONACyT, Mexico (no. 177603). Gerardo Pérez-Ponce de Leon gratefully acknowledges Institutional funds from ENES-Mérida and Instituto de Biología, UNAM. Maarten P. M. Vanhove was mainly supported for tilapia parasite research by the Research Foundation—Flanders (FWO-Vlaanderen) (research grant 1513419N), the Special Research Fund of Hasselt University (BOF20TT06 and BOF21INCENT09), and the Belgian Federal Science Policy Office (BRAIN-be Pioneer Project BR/132/PI/TILAPIA). Pravata Kumar Pradhan and Neeraj Sood would like to thank the Director of ICAR—National Bureau of Fish Genetic Resources, Lucknow for kindly providing the facilities for aspects of this work to be undertaken. Melba G. Bondad-Reantaso gratefully acknowledges the Food and Agriculture Organisation of the United Nations (FAO). In addition, we would like to extend our grateful thanks to the following for their kind permission to use selected images in this study: Liesl Van As and Andri Grobbelaar from the Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein, Republic of South Africa and the Editorial Office of African Zoology; Harrison Charo-Karisa, Shimaa Ali and John Benzie from WorldFish, Abbassa, Egypt and Penang, Malaysia and the Editorial Office of Aquaculture (Elsevier); Heba Hassan Mahboub and Adel A. Shaheen, Zagazig University, Egypt; Kwanprasert Panchai, Nakhon Ratchasima Rajabhat University and Chutima Hanjavanit, Khon Kaen University, Thailand; Mahmoud Abou-Okada from the Faculty of Veterinary Medicine, Cairo University, Egypt; Ha Thanh Dong, Asian Institute of Technology, Pathum Thani, Thailand; Supranee Chinabut, Bangkok, Thailand; Tarinee Limakom, Fish Vet Group Asia, Thailand; Nehemiah Rindoria, Kisii University, Kenya; Johan Theron from the University of Limpopo, South Africa; Patience Chwe Igeh and Quinton Dos Santos from the University of Johannesburg, South Africa; Wouter Fannes, Royal Museum for Central Africa, Tervuren, Belgium; Volodimir Sarabeev, Zaporizhzhia National University, Ukraine; Radmila Repová, Institute ˇ of Parasitology, BC, CAS, Ceské Bud ˇ ejovice, Czech Republic; Leo Galli, ˇ Uruguay; and, to Giuseppe Paladini from the Institute of Aquaculture, University of Stirling, Scotland, UK. We are indebted to Greta Hanako Rosas Saito BSc, Scanning Electron Microscopy Technician, Red de Estudios Moleculares Avanzados, and to Mrs Gina Gallo Cadena, Graphic Designer, Red TIC's, Instituto de Ecología, A.C., Xalapa, Mexico for their invaluable contribution in the preparation and photography of parasite specimens for the figure plates. We would also like to thank Beng-Chu Kua from the National Fish Health Research Division, Fisheries Research Institute, Department of Fisheries Malaysia for kindly donating fixed samples of Zeylanicobdella arugamensis and Ratchakorn Wongwaradechkul, INVE (Thailand) Ltd. for photographs of leeches. Wilmien J. Luus-Powell (University of Limpopo), Maarten Van Steenberge (Royal Belgian Institute of Natural Sciences) and Arnaud Collard are cordially thanked for their input. Tim Benson, South Australian Museum, provided comment on the Latin names and parasite taxonomy. Open access publishing facilitated by James Cook University, as part of the Wiley-James Cook University agreement via the Council of Australian University Librarians

Fish belonging to Gobiidae are well represented in the Marchica lagoon on the Moroccan Mediterranean coast, both in terms of species richness and abundance, with the black goby (Gobius niger Linnaeus, 1758) being the dominant species. The present study aims to examine (1) the ecological traits of Gobius niger and its environmental drivers in the lagoon and (2) the potential lagoon-related footprint using morphometric, genetic and parasitological proxies. Systematic sampling covering the whole lagoon basin performed between October 2015 and November 2016 revealed year-long presence of G. niger throughout the lagoon with significantly low densities in winter. The higher abundances were recorded in the shallow bottoms of the lagoon inner margins on a variety of substrates (mud, muddy-sand, sandy-mud and fine sand) mostly covered by macroalgae and/or seagrass meadows. Multivariate analysis evidenced that depth and temperature were the important predictor variables explaining the spatial distribution of G. niger in the lagoon, with depth being the best model explaining about 33% of the total variability. Comparison of black goby populations from the Marchica lagoon with their counterparts from the adjacent Mediterranean coast of Morocco revealed that specimens caught at the sea are of a bigger size compared to the ones from the lagoon without any effect of the colour morphs observed (dark vs clear). Of the 180 gobies investigated, not a single one hosted the parasites we targeted in the parasitological approach, monogenean flatworms. The absence of population structuring, low genetic diversity and presence of common haplotypes indicate no apparent restriction in the gene flow between the two populations. Moreover, the morphometric differences and colour morphs observed seems to be due to the external environment rather than genetic differences. Gobius niger plays a key eco-trophic role by providing a link between benthic invertebrates and large predators. Therefore, ultimately, the shallow beds of the lagoon, where the species is abundant, are key habitats in the Marchica lagoon and need to be considered in all management plans aiming at the conservation of biodiversity and ecological processes.

Two specimens of Coptodon guineensis (Günther, 1862) were unexpectedly found in the Canal de Nador, Moulay Bousselham lagoon, almost 1000 km north of the Aabar River the northernmost river previously recorded. To confirm this identification nineteen measurements were recorded from each specimen and compared with other specimens of C. guineensis from Morocco and Mauritania. The COI gene was partially sequenced and compared with formerly published sequences of Coptodon species of the region. Both morphology and DNA revealed no differences with specimens from known populations of C. guineensis in Morocco.

Protoancylodiscoides essetchii n. sp. (Fig. 3) urn:lsid:zoobank.org:act: A9378DDC-B17B-4B22-895E-998E3BB734C6 HÔTES TYPES. — Clarotes laticeps (Rüppell, 1829). ÉTYMOLOGIE. — “ essetchii ” en hommage au professeur Paul Essetchi Kouamélan, directeur de l’unité de formation et de recherche (UFR) Biosciences de l’université Felix Houphouët-Boigny de Cocody, en Côte d’Ivoire. SPÉCIMENS ÉTUDIÉS. — 25 individus montés dans la solution de Malmberg. SPÉCIMENS TYPES. — Holotype. Côte d’Ivoire • Rivière Bagoué, Samorossoba; 9°52’N, 6°21’O; 24.X.2018; Bouah Enoutchy Fabrice leg.; MNHN-HEL-1353. Paratypes. Côte d’Ivoire • 1 spécimen; mêmes données que pour l’holotype; MNHN-HEL-1354 • 2 spécimens; mêmes données que pour l’holotype; MZH, http://id.luomus.fi/KV.656 & http:// id.luomus.fi/KV.657. HABITAT. — Branchies. LOCALITÉ TYPE. — Rivière Bagoué, Samorossoba (9°52’N, 6°21’O). AUTRE LOCALITÉ. — Samorosso (9°34’N, 6°30’O) et Guinguereni (9°32’N, 6°35’O). PRÉVALENCE (%). — 100. INTENSITÉ MOYENNE. — 14,5. DIAGNOSE. — Protoancylodiscoides essetchii n. sp. se rapproche, par la morphologie des pièces sclérifiées du hapteur, de P. mansourensis, P. auratum, P. combesi et P. valentini. Toutes ces espèces se caractérisent par des crochets dorsaux de grandes tailles, avec une longue garde repliée dans la partie terminale, un court manche; des crochets ventraux plus petits que les dorsaux et présentant des orifices à la base de la garde. Elles sont également proches par la morphologie de la barre transversale ventrale en forme de V plus ou au moins ouverte et par la présence d’un onchium médio-dorsal. Cependant, P. essetchii n. sp. diffère fondamentalement de P. mansourensis, P. auratum, P. combesi et P. valentini par la morphologie ou la taille des organes copulateurs mâle et femelle: 1) le pénis filiforme est beaucoup plus court chez P. essetchii n. sp. (154,4 µm vs 325 µm; 180 µm; 228 µm; 482 µm respectivement chez P. mansourensis, P. auratum, P. combesi et P. valentini); 2) le vagin généralement en forme de V chez P. essetchii n. sp. présente une seule spire dans sa partie proximale vs plusieurs spires (4 à 5; 2 à 3 et 3 à 4) respectivement chez P. mansourensis, P. combesi et P. valentini. DESCRIPTION Taille des adultes: 857 (706-1023) µm sur 133 (97-162) µm de largeur, au niveau de l’ovaire. Crochets dorsaux très grands [a = 65 (56-69) µm; b = 47 (44-50) µm, c = 4 (2-5) µm; d = 25 (21-28) µm; e = 21 (18-23) µm], garde repliée dans sa partie terminale, 6,9 fois plus longue que le manche très court, lame longue et arquée. Barre transversale dorsale simple, avec des extrémités légèrement élargies x = 33 (29-35) µm; w = 6 (5-6) µm. Crochets ventraux [a = 32 (31-34) µm; b = 30 (25-32) µm; c = 2 (2-3) µm; d = 16 (12-18) µm; e = 19 (16- 21) µm], deux fois plus petits que les dorsaux, garde longue, manche court, avec une carène à extrémité renflée dans la partie concave de la lame, filament de la carène coiffant la lame. Barre transversale ventrale, avec deux barres jointives en forme de V x = 34 (32-36) µm; w = 6 (4-6) µm. Crochetons I, III et IV [28 (23-31) µm; 24 (20-27) µm; 31 (28-32) µm], plus longs que les crochetons II, V, VI, VII de longueur comprise entre 14 et 16 µm. Onchium médio-dorsal présent L = 20 (16-22) µm; l = 15 (11-18) µm. Pénis, tubulaire, long et filiforme Pe = 154 (114-190) µm. Pièce accessoire complexe Pa = 68 (51-83) µm. Vagin en forme de V, ouvert dans sa partie distale Lvg = 96 (77-109) µm.

Protoancylodiscoides ivoiriensis n. sp. (Fig. 4) urn:lsid:zoobank.org:act: 0A8CFD10-BF11-4FFB-92C5-2F303A944286 H��TES TYPES. ��� Clarotes laticeps (R��ppell, 1829). ��TYMOLOGIE. ��� ��� ivoiriensis ���en r��f��rence �� la C��te d���Ivoire. SP��CIMENS ��TUDI��S. ��� 20 individus mont��s dans la solution de Malmberg. SP��CIMENS TYPES. ��� Holotype. C��te d���Ivoire ��� Rivi��re Bagou��, Samorossoba; 9��52���N, 6��21���O; 24.X.2018; Bouah Enoutchy Fabrice leg.; MNHN-HEL-1355. Paratypes. C��te d���Ivoire ��� 1 specimen; m��mes donn��es que pour l���holotype; MNHN-HEL-1356 ��� 1 specimen; m��mes donn��es que pour l���holotype; MZH, http://id.luomus.fi/KV.658. HABITAT. ��� Branchies. LOCALIT�� TYPE. ��� Rivi��re Bagou��, Samorossoba (9��52���N, 6��21���O). AUTRE LOCALIT��. ��� Samorosso (9��34���N, 6��30���O). PR��VALENCE (%). ��� 25. INTENSIT�� MOYENNE. ��� 7. DIAGNOSE. ��� Cette esp��ce diff��re de toutes ses cong��n��res pr��c��demment d��crites dans ce genre, principalement par la morphologie des crochets dorsaux et ventraux et par l���absence d���onchium dans le hapteur. Les crochets dorsaux larges, ne pr��sentent pas une garde courb��e dans la partie terminale. Les crochets ventraux, contrairement aux autres esp��ces d��j�� d��crites dans ce genre, se caract��risent par une longue garde et un long manche bien diff��renci��s. Les crochetons I, III, et IV, �� la diff��rence de ce que l���on observe chez les autres esp��ces du genre, ont conserv��s leur taille larvaire tout comme c���est le cas pour les crochetons II, V, VI, VII. DESCRIPTION Taille des adultes: 1093 (623-1429) ��m sur 215 (139- 302) ��m de largeur, au niveau de l���ovaire. Crochets dorsaux larges, garde longue, manche tr��s court, lame longue, arqu��e �� longue pointe, a = 61 (55-65) ��m; b = 50 (43-51) ��m; c = 3 (3-4) ��m; d = 28 (24-31) ��m; e = 28 (23-31) ��m. Barre transversale dorsale l��g��rement incurv��e, plus ou moins renfl��e dans sa partie m��diane avec des extr��mit��s tr��s ��paisses x = 29 (27-34) ��m; w = 3 (2-4) ��m. Crochets ventraux plus petits que les dorsaux, garde longue, manche long, parcouru par une car��ne �� filament coiffant une lame arqu��e, �� pointe courte, a = 27 (24-28) ��m; b = 23 (21-24) ��m; c = 7 (6-8) ��m; d = 16 (15-18) ��m; e = 12 (9-14) ��m. Barre transversale ventrale, en forme de V avec de deux barres jointives aux extr��mit��s l��g��rement renfl��es, x= 29 (27-34) ��m; w = 3 (2-4) ��m. Crochetons I, II, III, IV, V, VI, VII tous a l�����tat larvaire, longueur comprise entre 15 et 17 ��m. P��nis long et filiforme Pe = 103 (74- 116) ��m. Pi��ce accessoire complexe Pa = 44 (35-50) ��m. Vagin Vg = [n=5, 77 (85,5-68) ��m] l��g��rement scl��rifi��, long et tubulaire, avec une ouverture en forme d���entonnoir dans sa partie distale., Published as part of Bouah, Enoutchy Fabrice, N'Douba, Valentin & Pariselle, Antoine, 2021, Deux nouveaux Protoancylodiscoides Paperna, 1969 (Monogenea, Ancyrocephalidae) parasites branchiaux de Clarotes laticeps (R��ppell, 1829) (Siluriformes, Claroteidae) en C��te d'Ivoire, pp. 155-162 in Zoosystema 43 (9) on pages 160-161, DOI: 10.5252/zoosystema2021v43a9, http://zenodo.org/record/4662824

Bouah, Enoutchy Fabrice, N'Douba, Valentin, Pariselle, Antoine (2021): Deux nouveaux Protoancylodiscoides Paperna, 1969 (Monogenea, Ancyrocephalidae) parasites branchiaux de Clarotes laticeps (Rüppell, 1829) (Siluriformes, Claroteidae) en Côte d'Ivoire. Zoosystema 43 (9): 155-162, DOI: 10.5252/zoosystema2021v43a9

Genre Protoancyrodiscoides Paperna, 1969 ESP��CE TYPE. ��� Protoancyrodiscoides chrysichthys Paperna, 1969. DIAGNOSE DU GENRE. ��� Ancyrocephalidae: hapteur avec quatre crochets (deux dorsaux, deux ventraux); deux barres transversales (une dorsale, une ventrale compos��e de deux scl��rites jointifs en forme de V); quatorze crochetons; un ou deux onchia pr��sents ou absents; trois paires de glandes c��phaliques; deux paires de taches oculaires sans cristallin; branches intestinales unies post��rieurement; testicule post��rieur intercaecal; canal d��f��rent entourant la branche intestinale gauche; une v��sicule s��minal; p��nis tubulaire avec pi��ce accessoire entourant l���extr��mit�� distale; un r��servoir prostatique; ovaire m��dian pr��-testiculaire; ouverture vaginale lat��rale gauche; canal vaginal contourn�� ou non; r��ceptacle s��minal pr��sent. Parasites des poissons siluriformes de la famille des Claroteidae et des Malapteruridae., Published as part of Bouah, Enoutchy Fabrice, N'Douba, Valentin & Pariselle, Antoine, 2021, Deux nouveaux Protoancylodiscoides Paperna, 1969 (Monogenea, Ancyrocephalidae) parasites branchiaux de Clarotes laticeps (R��ppell, 1829) (Siluriformes, Claroteidae) en C��te d'Ivoire, pp. 155-162 in Zoosystema 43 (9) on page 157, DOI: 10.5252/zoosystema2021v43a9, http://zenodo.org/record/4662824, {"references":["PAPERNA I. 1969. - Monogenetic trematodes of fish of the Volta basin and south Ghana. Bulletin de l'Institut francaise d'Afrique Noire 31: 840 - 880."]}

Parasites may have strong eco-evolutionary interactions with their hosts. Consequently, they may contribute to host diversification. The radiation of cichlid fish in Lake Victoria provides a good model to study the role of parasites in the early stages of speciation. We investigated patterns of macroparasite infection in a community of 17 sympatric cichlids from a recent radiation and 2 older species from 2 nonradiating lineages, to explore the opportunity for parasite-mediated speciation. Host species had different parasite infection profiles, which were only partially explained by ecological factors (diet, water depth). This may indicate that differences in infection are not simply the result of differences in exposure, but that hosts evolved species-specific resistance, consistent with parasite-mediated divergent selection. Infection was similar between sampling years, indicating that the direction of parasite-mediated selection is stable through time. We morphologically identified 6 Cichlidogyrus species, a gill parasite that is considered a good candidate for driving parasite-mediated speciation, because it is host species-specific and has radiated elsewhere in Africa. Species composition of Cichlidogyrus infection was similar among the most closely related host species (members of the Lake Victoria radiation), but two more distantly related species (belonging to nonradiating sister lineages) showed distinct infection profiles. This is inconsistent with a role for Cichlidogyrus in the early stages of divergence. To conclude, we find significant interspecific variation in parasite infection profiles, which is temporally consistent. We found no evidence that Cichlidogyrus-mediated selection contributes to the early stages of speciation. Instead, our findings indicate that species differences in infection accumulate after speciation.

Species interactions are a key aspect of evolutionary biology. Parasites, specifically, are drivers of the evolution of species communities and impact biosecurity and public health. However, when using interaction networks for evolutionary studies, interdependencies between distantly related species in these networks are shaped by ancient and complex processes. We propose using recent interacting host-parasite radiations, e.g. African cichlid fishes and cichlid gill parasites belonging toCichlidogyrus(Dactylogyridae, Monogenea), as macroevolutionary model of species interactions. The cichlid-Cichlidogyrusnetwork encompasses 138 parasite species and 416 interactions identified through morphological characteristics and genetic markers in 160 publications. We discuss the steps required to develop this model system based on data resolution, sampling bias, and reporting quality. In addition, we propose the following steps to guide efforts for a macroevolutionary model system for species interactions: first, evaluating and expanding model system outcome measures to increase data resolution; second, closing knowledge gaps to address underreporting and sampling bias arising from limited human and financial resources. Identifying phylogenetic and geographic targets, creating systematic overviews, enhancing scientific collaborations, and avoiding data loss through awareness of predatory journal publications can accelerate this process; and third, standardising data reporting to increase reporting quality and to facilitate data accessibility.

Cichlids in Morocco are relict populations of the fauna that was extant during the last glacial episodes. In recent millennia, these fishes underwent numerous bottleneck episodes that led to a significant reduction in their numbers. While the literature reports the presence of three (3) genera (Oreochromis, Coptodon, Sarotherodon) and four (4) species (O. aureus, C. guineensis, C. zillii, S. galilaeus) in Morocco, an intensive search for these fishes throughout this country and a thorough genetic and morphometric study in fact revealed the presence of only two (2) genera (Oreochromis, Coptodon) and four (4) species: three (3) native (O. aureus, C. guineensis, C. zillii) and one (1) introduced (O. niloticus). Sarotherodon galilaeus was not found, even in the watershed from which it was originally reported. Species encountered were identified morphologically and their identification was confirmed genetically (ND2/COI). For O. niloticus, we found two haplotypes with a difference of 7.5 % between Oued Sebou and Oued Bouregreg watersheds. For C. guineensis sampled in Oued Aabar and Sebkha Imlili, a taxonomic incongruence occurred on the basis of significant differences between seventeen (17) of the thirty-seven (37) morphometric characters studied (including dentition).

Three new species of Synodontella Dossou & Euzet, 1993 are described from two species of Synodontis (Mochokidae) collected from the middle course of the Boumba River (East Cameroon): Synodontella angustupenis n. sp. from Synodontis nummifer, Synodontella longipenis n. sp. and Synodontella simplex n. sp. from Synodontis decorus. These new species are different from the other Synodontella species already described due to their horseshoe-shaped dorsal transverse bars. Synodontella angustupenis differs from S. longipenis and S. simplex by the morphology of its penis, a thin tube, and its accessory piece, bifid at its extremity. Synodontella longipenis differs from the other two species by the morphology and the size of its male copulatory organ, which is very long. Synodontella simplex differs from S. angustupenis and S. longipenis by the shape of its penis, which is simple, and of its accessory piece, with a developed heel. The difference between the dorsal transverse bars of Synodontella species from the Sanaga River in Cameroon (and other localities in Africa), slightly curved, and those from the Boumba River, horseshoe-shaped, makes it possible to separate Synodontella species into two different subgroups. This difference can be explained by a long isolation period of the hosts, living in different river basins, followed by the divergence of the parasite populations (vicariant speciation).

Tilapias are important aquaculture fishes that have been introduced widely all over the world, often carrying their monogenean parasites with them. An extensive investigation on monogeneans of invasive tilapias was conducted in 19 natural water sources in south China between July 2015 and December 2017. We found nine known species of monogeneans, i.e., Enterogyrus coronatus, E. malmbergi, Cichlidogyrus cirratus, C. halli, C. sclerosus, C. thurstonae, C. tilapiae, Scutogyrus longicornis, Gyrodactylus cichlidarum, and one unknown Gyrodactylus species. In addition to reporting ten new hosts and four new geographical records, we observed new morphological characteristics of these species. Observation on living specimens of Enterogyrus spp. demonstrated that these two species have characteristic opisthaptoral retraction capacities, while the opisthaptor glands were not observed in our specimens of E. coronatus and E. malmbergi. The morphological differences of the accessory piece of the male copulatory complex between C. cirratus and C. mbirizei (character for species differentiation) could result from the observation at different perspectives, which indicates that C. mbirizei is likely a synonym of C. cirratus. A more detailed structure of the sclerotized parts of Cichlidogyrus spp. and S. longicornis were revealed by scanning electron microscopy. As was the case for the monogeneans found on alien tilapias from other geographic regions, the present study confirmed the high potential of these monogeneans to establish populations in new habitats.

The Lower Congo Basin is characterized by a mangrove-lined estuary at its mouth and, further upstream, by many hydrogeographical barriers such as rapids and narrow gorges. Five localities in the mangroves and four from (upstream) left bank tributaries or pools were sampled. On the gills of Coptodon tholloni, Coptodon rendalli, Hemichromis elongatus, Hemichromis stellifer and Tylochromis praecox, 17 species of parasites (Dactylogyridae & Gyrodactylidae, Monogenea) were found, eight of which are new to science. Six of these are herein described: Cichlidogyrus bixlerzavalai n. sp. and Cichlidogyrus omari n. sp. from T praecox, Cichlidogyrus calycinus n. sp. and Cichlidogyrus polyenso n. sp. from H. elongatus, Cichlidogyrus kmentovae n. sp. from H. stellifer and Onchob-della ximenae n. sp. from both species of Hemichromis. On Cichlidogyrus reversati a ridge on the accessory piece was discovered that connects to the basal bulb of the penis. We report a putative spillback effect of the native parasites Cichlidogyrus berradae, Cichlidogyrus cubitus and Cichlidogyrus flexicolpos from C. tholloni to the introduced C. rendalli. From our results, we note that the parasite fauna of Lower Congo has a higher affinity with the fauna of West African and nearby freshwater ecoregions than it has with fauna of other regions of the Congo Basin and Central Africa.

Based on Cichlidogyrus sp. (Monogenea, Ancyrocephalidae) specimens from Hemichromis sp. hosts, we tested the influence of different methods to fix/preserve samples/specimens [frozen material, alcohol or formalin preserved, museum process for fish preservation (fixed in formalin and preserved in alcohol)] and different media used to mount the slides [tap water, glycerin ammonium picrate (GAP), Hoyer's one (HM)] on the size/shape of sclerotized parts of monogenean specimens. The results show that the use of HM significantly increases the size of haptoral sclerites [marginal hooks I, II, IV, V, and VI; dorsal bar length, width, distance between auricles and auricle length, ventral bar length and width], and changes their shape [angle opening between shaft and guard (outer and inner roots) in both ventral and dorsal anchors, ventral bar much wider, dorsal one less curved]. This influence seems to be reduced when specimens/samples are fixed in formalin. The systematics of Monogenea being based on the size and shape of their sclerotized parts, to prevent misidentifications or description of invalid new species, we recommend the use of GAP as mounting medium; Hoyer's one should be restricted to monogenean specimens fixed for a long time which are more shrunken.

Twelve specimens of Heterobranchus longifilis sampled from the River Boumba were examined for their monogenean gill parasites. Quadriacanthus longifilisi N'Douba,Lambert & Euzet 1999 and Q. thysi N'Douba, Lambert & Euzet 1999 are newly recorded in the studied locality. Three new species have also been described: Q. tricorniculai n. sp., Q. triunguisin. sp., and Q. ndoubai n. sp. Quadriacanthus tricorniculai and Q. triunguisi are characterized by the unique morphology of their accessory pieces, which end in a three-head hydrashapedstructure, with tentacles being longer in Q. tricorniculai; proximal extremity of accessorypiece is stronger for Q. triunguisi, while Q. ndoubai is distinguished by the size of its male copulatory organ (larger than 80 mu m) and the fork shaped distal extremity of the accessory piece of the male copulatory complex. The variability of monogenean species richness of Hetero-branchus longifilis between Ivory Coast and Cameroon is discussed.

Host specimens were sampled in the River Sanaga (Cameroon) from January to October 2014 and August 2015. Three new species, Protoancylodiscoides sanagaensis n. sp., Protoancylodiscoides valentini n. sp. from Chrysichthys nigrodigitatus and Chrysichthys longidorsalis in the middle course and downstream, Protoancylodiscoides spirovagina n. sp. from Chrysichthys nigrodigitalus downstream, are herein described. These new helminths differ from the congeneric species by the size of the haptoral sclerites, the male copulatory organ and the morphology of the vagina.

Protoancylodiscoides combesi Bassock Bayiha, Nack & Pariselle (Fig. 4) Type host. Chrysichthys auratus Geoffroy Saint-Hilaire. Site. Secondary gill lamellae. Type locality. Nachtigal (4��21'10.5'' N; 11��37'34.9'' E, alt. 432 m). Other localities. Mbandjock (4��28'21.3'' N; 11��53'5.7'' E, alt. 543 m), Nanga-Eboko (4��44'36.4'' N; 12��25'41.9'' E, alt. 578 m) and Belabo (4��57'47.3'' N; 13��17'36.1'' E, alt. 615 m). Other hosts. Chrysichthys nigrodigitatus (Lac��p��de) and C. longidorsalis Risch & Thys van den Audenaerde. Prevalence. 66.6% in C. auratus, 3.4% in C. nigrodigitatus and 33.3% in C. longidorsalis. Mean intensity. 10.2 �� 20 in C. auratus, 5 �� 0 in C. nigrodigitatus and 42 �� 14.2 in C. longidorsalis. Etymology. The name combesi was given to this species by Dossou in 1985, but not officially published nor illustrated, in honor of Professor C. Combes from the University of Perpignan / France for his great contribution to the knowledge of parasites. Specimens deposited. 1 Holotype MRAC n�� 37931 and 4 paratypes MRAC n�� 37932. Description (based on 31 individuals). Dorsal anchor with long and thick guard, with distal end thinner and outwardly curved, short shaft, and conical blade arched with a long point. Presence of a thick filament. Transverse dorsal bar slightly curved with rounded ends pierced with circular holes. Ventral anchors having short shaft and perpendicularly developed triangular guard with eccentric triangular fenestration. Presence of a diagonal hull and a thick filament attached to its posterior extremity. Blade ending with a short fine tip. Ventral bar made up of two symmetric arms separated medially. Haptoral hooks with the same organization as in the previous species: medioventral hook pairs I [I] and IV [VII] with a thick and long shaft; latero-ventral hooks II [V] and hooks V [IV], VI [III], VII [II] with similar shape and size (thin, without shank); latero-dorsal hooks III [VI] with poorly developed shank. Presence of a longer than wide dorsal onchium. Copulatory complex formed by a tubular penis (Pe) associated with a complex globular oval accessory piece. Vagina sclerotized spiral flared at its base and distal part. The measurements of haptoral and reproductive systems are provided in Table I. Remarks. Protoancylodiscoides combesi resembles P. mansourensis, P. chrysichthes and P. auratum by the general morphology of the hard parts of the haptor and of the accessory piece. However, it differs from P. mansourensis by the size of the ventral bar 34 (29���38) vs 41(38���43), of the dorsal anchor 66 (61���73) vs 88 (81���93), and of the penis 228 (132���299) vs 325 (302���347). Protoancylodiscoides combesi also differs from P. mansourensis, P. chrysichthes and P. auratum by the morphology of the vagina which, in P. combesi, is spirally coiled with 2���3 rings (diameter 10 to 13 ��m), unlike the other three species where there are 4 to 5 rings for P. mansourensis (diameter 24 to 27 ��m), P. chrysichthes (diameter 13 to 20 ��m) and P. auratum (diameter 8 to 12 ��m). These three species may also be differentiated from one another by the shape of the distal third of the vagina which is coiled in P. chrysichthes, turned up and cup shaped in P. auratum, and straight in P. combesi., Published as part of Bassock Bayiha, Etienne D., Nack, Jacques, Pariselle, Antoine & Bilong Bilong, Charles F., 2016, Two new species of gill parasites assigned to Protoancylodiscoides (Monogenea, Ancyrocephalidae) from Chrysichthys spp. (Siluriformes, Claroteidae) in River Sanaga (Cameroon), pp. 178-186 in Zootaxa 4170 (1) on pages 183-184, DOI: 10.11646/zootaxa.4170.1.11, http://zenodo.org/record/259827

Protoancylodiscoides auratum Bassock Bayiha, Nack & Pariselle ( Fig. 3) Type host. Chrysichthys auratus Geoffroy Saint-Hilaire. Site. Secondary gill lamellae. Type Locality. Nachtigal (4��21'10.5'' N; 11��37'34.9'' E, alt. 432 m). Other localities. Mbandjock (4��28'21.3'' N; 11��53'5.7'' E, alt. 543 m), Nanga-Eboko ( 4��44'36.4'' N; 12��25'41.9'' E, alt. 578 m) and Belabo (4��57'47.3'' N; 13��17'36.1'' E, alt. 615 m) Prevalence. 58% (14 of 24 C. auratus infected). Mean intensity. 3.4 �� 3.7. Specimens deposited. Holotype MRAC n�� 37929 and paratype MRAC n�� 37930. Etymology. The name auratum refers to the host and has been given to this species by Dossou in 1985, but not officially published (nor illustrated). Description (based on 21 individuals). The new species belongs to Protoancylodiscoides Paperna, 1969 as diagnosed by N���Douba (2000). Dorsal anchor with long and thick guard (= outer root, superficial root), distal end thinner and outwardly curved; shaft (= handle, inner root, deep root) shorter than guard; sharp and curved blade with thick base; presence of a thick filament. Dorsal transverse bar slightly curved anteriorly; both bilobed extremities separated from the central section by a constriction, anterior lobe with a hook folded medially. Ventral anchors with fenestration between shaft and guard; guard longer than shaft, presence of a hull starting at the front end of the shaft, running diagonally up to the base of the blade, blade ending in a short point; presence of a thick filament fixed to the distal end of the hull. Ventral transverse bar made up of two straight symmetrical arms separated medially. Presence of 7 pairs and 3 types of haptoral hooks according to their shape, size and position: latero-ventral hooks II [V], V [IV], VI [III], VII [II] of similar shape and size [i.e. thin, without shank (= distal subunit)], resembling those present in ancyrocephalid oncomiracidia (larval hook), corresponding to the proximal subunit (= handle + thumb + point) in Kristsky and Kulo (1999); medio-ventral hook pairs I [I] and IV [VII] enlarged with a thick and long shank; latero-dorsal hooks III [VI] with poorly developed shank. Presence of a longer than wider dorsal onchium. Copulatory complex, close to the pharynx, formed by a thin tubular penis (Pe) associated with a very complex globular accessory piece. Vagina coiled at its proximal part, then folded at the anterior part terminating by a cup shaped structure. The measurements of haptoral and reproductive sclerites are shown in Table 1. Specific names P. auratum P. combesi P. mansourensis P. chrysichthes in El-Naggar (1987) in Kritsky & Kulo (1999) Remarks. By the general morphology of the haptoral sclerites and of the accessory piece, P. a ur a t u m is close to P. mansourensis and P. chrysichthes previously described from C. auratus and C. nigrodigitatus, respectively. However it differs from P. mansourensis by the size of the ventral bar 36 (32���38) vs 41 (38���43) and of the dorsal anchor 64 (56���70) vs 88 (81���93). Protoancylodiscoides auratum also differs from these two species by the penis length 180 (141���217) vs 325 (302���347) and 255 (162���365) for P. mansourensis and P. chrysichthes respectively, and by the morphology of the vagina: its distal portion is simple but flared in P. mansourensis; it is turned up and cup shaped in P. auratum, but coiled in P. chrysichthes., Published as part of Bassock Bayiha, Etienne D., Nack, Jacques, Pariselle, Antoine & Bilong Bilong, Charles F., 2016, Two new species of gill parasites assigned to Protoancylodiscoides (Monogenea, Ancyrocephalidae) from Chrysichthys spp. (Siluriformes, Claroteidae) in River Sanaga (Cameroon), pp. 178-186 in Zootaxa 4170 (1) on pages 181-183, DOI: 10.11646/zootaxa.4170.1.11, http://zenodo.org/record/259827, {"references":["Paperna, I. (1969) Monogenetic trematodes of the fish of the Volta Bassin and south Ghana. Bulletin de l'Institut francaise d'Afrique Noire, Serie A, XXXI, 840 - 880.","Kritsky, D. C. & Kulo, S. D. (1999) Revisions of Protoancylodiscoides and Bagrobdella, with Redescription of P. chrysichthys and B. auchenoglanii (Monogenoidea: Dactylogyridae) from the Gill of Two Bagrid Catfish (Siluriformes) in Togo, Africa. Journal of the Helminthological Society of Washington, 66, 138 - 145","El-Naggar, M. M. (1987) Protoancylodiscoides mansourensis n. sp. a monogenean gill parasite of the Egyptian freshwater fish Chrysichthys auratus Geoffroy, 1809. Arab Gulf Journal of Scientific Research, Agricultural and Biological Science, B 5, 441 - 454."]}