Unlike their marine counterparts, tropical freshwater clupeids receive little scientific attention. However, they sustain important fisheries that may be of (inter)national commercial interest. Africa harbours over 20 freshwater clupeid species within Pellonulini. Recent research suggests their most abundant parasites are gill-infecting monogenean flatworms within Kapentagyrus. After inspecting specimens of 12 freshwater clupeids from West and Central Africa, mainly sourced in biodiversity collections, we propose 11 new species of Kapentagyrus which we describe using their haptoral and genital morphology. Because of their high morphological similarity, species delineation relies mostly on morphometrics of anchors and hooks. Specifically, earlier, molecular taxonomic work indicated that the proportion between the length of the anchor roots, and between hook and anchor length, are diagnostic. On average, about one species of Kapentagyrus exists per pellonuline species, although Pellonula leonensis harbours four species and Microthrissa congica two, while Microthrissa moeruensis and Potamothrissa acutirostris share a gill monogenean species. This study more than quadruples the number of known species of Kapentagyrus, also almost quadrupling the number of pellonuline species of which monogeneans are known. Since members of Kapentagyrus are informative about their hosts’ ecology, evolutionary history, and introduction routes, this enables a parasitological perspective on several data-poor African fisheries.

Gobies and their ectoparasitic monogenean flatworms are promising models for species diversification because of their species richness. Recent decades have seen the discovery of several new species of Gyrodactylus (Monogenea: Gyrodactylidae) on European gobies, mostly in the sand goby lineage and especially in the Eastern Mediterranean. However, the monogenean fauna of other gobies is much less understood. Therefore, we scrutinized five gobiid species (34 specimens, vouchered, with some representatives sequenced), sampled in Greece, for monogenean ectoparasites. Only specimens of the giant goby Gobius cobitis were infected; they harbored Xenoligophoroides cobitis (Monogenea: Dactylogyridae) on their gills. Here we provide the first record from Greece, and the first ITS rDNA and COI sequences of the representative of this monotypic genus. Also 28S rDNA was sequenced and compared with published data from across its known distribution, suggesting clinal variation. Lack of sequence data of closely related dactylogyrid monogeneans prevents either proposing a sister-group for Xenoligophoroides, or inferring a scenario explaining the presence of a single known member of this genus on gobies. Possible hypotheses include either the ancestral long-term presence on gobiids but “missing the boat” of the diversification events in the “Gobius-lineage”, or a recent host switch from a non-gobiid host.

To date, 41 species of Gyrodactylus have been described from Africa. However, none of these have been reported in Morocco. After identifying and examining 738 cyprinid host specimens, 26 specimens belonging to Gyrodactylus were found to parasitize the gills of nine species of Luciobarbus, Carasobarbus, and Pterocapoeta. The current study describes in detail 12 specimens of Gyrodactylus isolated from the gills of Luciobarbus pallaryi (Pellegrin, 1919) and Luciobarbus ksibi (Boulenger, 1905). Based on morphoanatomical observations, the characterization of the specimens collected suggests a species of Gyrodactylus new to science, described here as Gyrodactylus nyingiae n. sp. The new species is different from previously described gyrodactylids infecting African cyprinid hosts because it has a longer hamulus total length, a longer hamulus root, a downward projecting toe, a trapezium shaped ventral bar membrane with slightly striated median portion and small rounded anterolateral processes. This study brings the total number of Gyrodactylus spp. found in African cyprinids to four.

: The ichthyofauna of Lake Tanganyika consists of 12 families of fish of which five belong to Siluriformes (catfishes). Studies on siluriforms and their parasites in this lake are very fragmentary. The present study was carried out to help fill the knowledge gap on the monogeneans parasitizing the siluriform fishes of Lake Tanganyika in general and more particularly Clarias gariepinus. The gills of a specimen of Clarias gariepinus (Clariidae) were examined for ectoparasites. We identified the monogenean Gyrodactylus transvaalensis (Gyrodactylidae). This is the first time this parasite was found infecting gills. We are the first to observe a large spine in the male copulatory organ of this species, and to provide measurements of its genital spines; this completes the description of the male copulatory organ which is important in standard monogenean identification. This is the first monogenean species reported on C. gariepinus at Lake Tanganyika and the third known species on a representative of Siluriformes of this lake. It brings the total number of species of Gyrodactylus recorded in Lake Tanganyika to four. Knowing that other locations where this species has been reported are geographically remote from Lake Tanganyika, we propose a “failure to diverge” phenomenon for G. transvaalensis.