Endohelminth diversity in the invasive Clarias gariepinus (Burchell, 1822) from two freshwater lakes: Naivasha and Ol'Bolossat, Kenya.

Fish parasitology contributes to our understanding of the potential risks posed by diverse groups of parasitic organisms on fish stocks in either wild and culture systems. This study was conducted in May 2023 and aimed at assessing the diversity of endohelminths in the invasive North African catfish Clarias gariepinus (Burchell, 1822) obtained from two freshwater lakes, Naivasha and Ol'Bolossat, in Kenya. Parasitological examination of 66 and 35 fish samples collected from the two lakes respectively was achieved using light and scanning electron microscopy methods. Results revealed endohelminth diversity broadly classified as four digeneans, two nematodes, and one cestode. Seven taxa of endohelminths were found in C. gariepinus samples, but only four of these taxa could be identified up to the species level. Six of the taxa (Diplostomum sp., Tylodelphys mashonense, Plagiorchioidea sp., Paracamallanus cyathopharynx, Contracaecum sp., and Tetracampos ciliotheca) were common in samples from the two lakes. Glossidium pedatum only occurred in samples from Lake Ol'Bolossat. Parasite prevalence ranged from 8.6 (T. mashonense) to 100% (Diplostomum sp., T. ciliotheca, and Contracaecum sp.) and mean intensity from 1.4 (T. mashonense) to 16.9 (Diplostomum sp.). The diversity and richness indices were comparatively higher in fish samples from Lake Ol'Bolossat and attributed to the occurrence of G. pedatum in the Ol'Bolossat. However, parasitic infestation of fish samples from the two lakes depicted close similarity, both in diversity and prevalence. These findings form an important baseline data for further follow-up studies, and they suggest the need for further molecular analyses to fully describe three of the taxa only identified up to the genus level.

Gyrodactylus serrai n. sp. (Gyrodactylidae), from the Near-Threatened Clanwilliam Sawfin, Cheilobarbus serra (Peters) (Cyprinidae, Smilogastrinae), in the Cape Fold Ecoregion, South Africa.

A new species of Gyrodactylus is described from the gills of the near-threatened Clanwilliam sawfin, Cheilobarbus serra (Smiliogastrinae) collected from the Matjies River, Cape Fold Ecoregion, Western Cape Province, South Africa. Morphometry and morphology of the haptoral hard parts (hamuli, bars and marginal hooks) of Gyrodactylus serrai n. sp. differ from the other known species of the genus in the smaller size of hamuli and the shape and size of marginal hooks. Furthermore, ITS rDNA for the new species is unique among available Gyrodactylus spp. data in GenBank. Based on the uncorrected p-distances, G. serrai n. sp. is genetically most closely related to Gyrodactylus moroccensis Rahmouni, 2023 and Gyrodactylus pseudomoroccensis Rahmouni, 2023 from two species of Luciobarbus (Barbinae) from northern Africa, with interspecific divergence of 8.7% and 8.8%, respectively. The presence of a median ridge in the terminal part of the ventral bar membrane at G. serrai n. sp. most probably represents a morphological link to the North African Gyrodactylus spp. that suggests a morphogenetic association across the African continent as a result of ancient waterways that facilitated the dispersion of cyprinids and their parasite fauna or an independent evolution event retaining similarities from a common ancestor. The description of Gyrodactylus serrai n. sp. represents only the second species of Gyrodactylus described from an endemic South African cyprinid host, underscoring the need for focused research on this group of fishes to provide a sound understanding of the parasitic communities of these highly threatened and poorly studied hosts.

A histological evaluation of pansteatitis-affected Mozambique tilapia, Oreochromis mossambicus (Peters 1852), from different geographical locations in South Africa.

Pansteatitis is the leading cause for the decline in Nile crocodile populations and the sporadic mortality of fish in the Olifants River System, South Africa. To determine the prevalence of this disease in lentic systems, Mozambique tilapia, Oreochromis mossambicus, were collected from Lake Loskop, Lake Flag Boshielo, Phalaborwa Barrage and Lake Luphephe-Nwanedi. The former three impoundments are located within the main stem of the Olifants River, while the latter, which is geographically isolated and situated in the Limpopo River System, served as a reference site. Mesenteric adipose, liver, serosa of the swim bladder, gill and the skeletal muscle of fish sampled were examined for gross and microscopic evidence of pansteatitis. Microscopically observed changes were used to statistically compare pansteatitis prevalence between samples and sites. Based on histopathological evaluation, the adipose tissue in the liver, swim bladder serosa and coelom from severely debilitated individuals showed the most significant pathological changes. Lesions indicative of steatitis were observed in fish collected from Lake Loskop (75%), Lake Flag Boshielo (22%) and Lake Luphephe-Nwanedi (15%). Further investigation is warranted to understand the pervasiveness and mechanisms driving pathological changes of pansteatitis at Lake Flag Boshielo, Phalaborwa Barrage and Lake Luphephe-Nwanedi.

Metal levels in two fish species from a waterbody impacted by metallurgic industries and acid mine drainage from coal mining in South Africa.

The Loskop Dam in South Africa is the most contaminated waterbody in the Olifants River which is a transboundary river that flows into Mozambique. The present study measured selected metal concentrations in the muscle of Labeo rosae and Oreochromis mossambicus from Loskop Dam, and assessed the human health risks associated with consumption of these fish species. Trace metals were below detection level in the surface water whereas bottom sediment exhibited relatively higher concentrations. A significant seasonal variations (p < 0.05) as well as inter-species difference (p < 0.05) of metal concentrations were observed in the fish muscle. Selenium concentration showed to have increase over the recent few years. Concentrations exceeding permissible level for human consumption was recorded for As, Se and Sb in both species. Other metals which THQ > 1 was Cr for L. rosae and Co for O. mossambicus. The current study shows that there could be some serious health and environmental implications for rural communities making use of Loskop Dam fish as food source. These findings add to knowledge in Africa, particularly South Africa, where other fish species have been identified as being potentially dangerous for human consumption in terms of Se, Sb, As, Co and Cr levels.

Lipidomics for wildlife disease etiology and biomarker discovery: a case study of pansteatitis outbreak in South Africa.

INTRODUCTION: Lipidomics is an emerging field with great promise for biomarker and mechanistic studies due to lipids diverse biological roles. Clinical research applying lipidomics is drastically increasing, with research methods and tools developed for clinical applications equally promising for wildlife studies. OBJECTIVES: Limited research to date has applied lipidomics, especially of the intact lipidome, to wildlife studies. Therefore, we examine the application of lipidomics for in situ studies on Mozambique tilapia (Oreochromis mossambicus) in Loskop Dam, South Africa. Wide-scale mortality events of aquatic life associated with an environmentally-derived inflammatory disease, pansteatitis, have occurred in this area. METHODS: The lipidome of adipose tissue (n = 31) and plasma (n = 51) from tilapia collected from Loskop Dam were characterized using state of the art liquid chromatography coupled to high-resolution tandem mass spectrometry. RESULTS: Lipid profiles reflected pansteatitis severity and were significantly different between diseased and healthy individuals. Over 13 classes of lipids associated with inflammation, cell death, and/or oxidative damage were upregulated in pansteatitis-affected adipose tissue, including ether-lipids, short-chained triglyceride oxidation products, sphingolipids, and acylcarnitines. Ceramides showed a 1000-fold increase in the most affected adipose tissues and were sensitive to disease severity. In plasma, triglycerides were found to be downregulated in pansteatitis-affected tilapia. CONCLUSION: Intact lipidomics provided useful mechanistic data and possible biomarkers of pansteatitis. Lipids pointed to upregulated inflammatory pathways, and ceramides serve as promising biomarker candidates for pansteatitis. As comprehensive coverage of the lipidome aids in the elucidation of possible disease mechanisms, application of lipidomics could be applied to the understanding of other environmentally-derived inflammatory conditions, such as those caused by obesogens.

Molecular data show Clinostomoides Dollfus, 1950 is a junior synonym of Clinostomum Leidy, 1856, with redescription of metacercariae of Clinostomum brieni n. comb.

The genus Clinostomoides Dollfus, 1950 was erected to accommodate a single worm from Ardea goliath sampled in the Belgian Congo. The specimen was distinguished from other clinostomids by its large size and posterior genitalia. In the following years, metacercariae of Clinostomoides brieni, have been described in Clarias spp. in southern and western Africa. A few authors have referred to Clinostomum brieni, but all such usages appear to be lapsus calami, and the validity of Clinostomoides remains widely accepted. In this study our aim was: position C. brieni among the growing clinostomids molecular database, and redescribe the species with emphasis on characters that have emerged as important in recent work. We sequenced two nuclear (partial 18S and ITS) and one mitochondrial marker (partial cytochrome c oxidase I) and studied morphology in metacercariae from hosts and localities likely to harbour the type species (Clarias spp., Democratic Republic of the Congo, South Africa). Phylogenetic analysis shows C. brieni belongs within Clinostomum Leidy, 1856. We therefore transfer C. brieni to Clinostomum, amend the diagnosis for the genus Clinostomum and provide a critical analysis of other species in Clinostomoides, all of which we consider species inquirendae, as they rest on comparisons of different developmental stages.

Morphological Studies of Developmental Stages of Oculotrema hippopotami (Monogenea: Polystomatidae) Infecting the Eye of Hippopotamus amphibius (Mammalia: Hippopotamidae) Using SEM and EDXA with Notes on Histopathology.

The present study was performed to observe histopathological effects of Oculotrema hippopotami Stunkard, 1924 infection in the eye of Hippopotamus amphibius, as well as to reveal new details of morphology and structural features of this monogenean and its comparison between 2 age stages of the parasite. This was done using both light and scanning electron microscopy, energy dispersive X-ray analysis (EDXA) and histopathology. The presence of a mixture of different generations (adult and sub-adult) in one host individual is common for Oculotrema Stunkard, 1924 in contrast to Polystoma Zeder, 1800. New metrical and graphical information obtained for adults and sub-adults compared with the previous studies. Here we show the presence of genital papillae in adults, metrical data on the distal part of the vas deferens. SEM micrographs of sperm ejaculatory structures and information about the flattened dorsal side of the body provided for the first time. Histopathological changes, such as necrosis and hemorrhage in host tissues as a result of O. hippopotami attachment structures are described. Structural analysis of different body parts of O. hippopotami of both age groups are also included. We show qualitative differences in the presence of hardening ions (S, P, Ca) in attachment structures (oral and haptor suckers) that increase with the age of the worm. The presence of sub-adults and adults on the same host, together with high levels of infection without high pathogenicity may account for Oculotrema being one of the most successful parasites among the Monogenea.

An annotated list and molecular data on larvae of gryporhynchid tapeworms (Cestoda: Cyclophyllidea) from freshwater fishes in Africa.

An annotated list of larvae (metacestodes) of gryporhynchid tapeworms (Cestoda: Cyclophyllidea) from freshwater fishes in Africa is provided with numerous new host and geographical records. Newly collected materials from Burundi, Democratic Republic of the Congo, Kenya, Madagascar, Namibia, Senegal, South Africa, Sudan and Zimbabwe practically double the total number of species reported from African fish so far. We confirm the occurrence of 16 species (five unidentified to the species level and most likely representing new taxa) belonging to the genera Amirthalingamia Bray, 1974 (1 species), Cyclustera Fuhrmann, 1901 (2 species), Dendrouterina Fuhrmann, 1912 (1 species), Neogryporhynchus Baer & Bona, 1960 (1 species), Paradilepis Hsü, 1935 (4 species), Parvitaenia Burt, 1940 (5 species), and Valipora Linton, 1927 (2 species). Additionally, metacestodes of four unidentified species of Paradilepis and Parvitaenia are reported from fish for the first time. Rostellar hooks of all species are illustrated and their measurements are provided together with a host-parasite list. The molecular phylogenetic analysis based on partial LSU rDNA sequences offers the first insight into the internal phylogenetic relationships within the family. Together with the morphological observations, the present study provides a taxonomic baseline for future studies on this largely neglected, but widely distributed and relatively frequent, group of parasites of African fishes, including economically important cichlids like tilapias and cyprinids.

Expanded description of Lamproglena cleopatra Humes, 1957 (Lernaeidae: Copepoda) from Labeo spp. (Cyprinidae) with a key to species of Lamproglena von Nordmann, 1832.

The occurrence of the copepod Lamproglena cleopatra Humes, 1957, parasitising freshwater fishes in the Limpopo River System is presented, along with new morphological data. This crustacean was originally described parasitising a cyprinid (Labeo forskalii Rüppell) from the River Nile, Egypt. During 2014-2015 crustacean samples were collected from the gills of three cyprinid fish species, Labeo rosae Steindachner from Flag Boshielo Dam, Labeo molybdinus Du Plessis from Nwanedi-Luphephe Dam in South Africa, and Labeo ruddi Boulenger from the River Bubye in Zimbabwe. The specimens from the present study were morphologically similar regardless of the host, but exhibited some morphometric intraspecific differences in comparison with the type-specimen from Egypt. A description of L. cleopatra copepodid III stage and a taxonomic key to Lamproglena spp. is provided.

A morphological and molecular study of Clinostomid metacercariae from African fish with a redescription of Clinostomum tilapiae.

The genus Clinostomum Leidy, 1856 (Digenea: Clinostomidae) has been reported in all ecozones of the world and a clear separation between the species of the 'Old World' and 'New World' has been recognized based on molecular studies. Recent works on Afrotropical species include redescriptions of C. cutaneum and C. phalacrocoracis, while C. tilapiae has yet to be studied using modern taxonomic approaches. In the present research, morphological redescription of C. tilapiae metacercariae from a new host, Synodontis batensoda sampled at Anambra River Basin, Nigeria, together with molecular analysis of nuclear internal transcribed spacer rDNA and cytochrome c oxidase 1 mtDNA are reported. We also provide morphological and molecular data from four further putative species of Clinostomum (morphotypes 1-4) from different areas of Africa, as well as the first report of C. phalacrocoracis in South Africa.

Guppies (Poecilia reticulata) introducing an alien parasite, Camallanus cotti (Nematoda: Camallanidae) to Africa, the first report.

Introduced alien fish species and their associated parasites may result in a serious threat to indigenous biodiversity. Furthermore, this may have negative impacts on cultured fish as well as on native parasitic fauna. In the present study, the invasive Asian nematode, Camallanus cotti Fujita, 1927 (Nematoda: Camallanidae), is reported from the guppy (Poecilia reticulata) for the first time in Africa. This parasite is assumed to be introduced into Africa along with the introduction of exotic poeciliid fishes, which are known to be the most common hosts of C. cotti in ornamental fish industry worldwide.The presence of this parasite in both aquarium-cultured fish as well as fish from natural waterbodies is evidence of the introduction of the alien organisms due to insufficient prophylactic veterinary control during transfer of non-native hosts between countries and the spread of them by the anthropogenic introduction to natural systems.

Description and phylogenetic position of a new species of Rhabdias Stiles et Hassall, 1905 (Nematoda: Rhabdiasidae) from the banded rubber frog, Phrynomantis bifasciatus (Smith) (Amphibia: Microhylidae), in South Africa.

The lung-dwelling nematode Rhabdias engelbrechti sp. n. was found in five of eight examined banded rubber frogs in Limpopo Province, South Africa. The species is differentiated from species of Rhabdias Stiles et Hassall, 1905 occurring in the Afrotropical Realm based on the presence of a globular cuticular inflation at the anterior end, the buccal capsule walls being distinctly divided into anterior and posterior parts, the buccal capsule size (6-9 µm × 16-18 µm), and the body length (3.8-6.1 mm). Rhabdias engelbrechti is the tenth species of the genus found in Afrotropical anurans. Our molecular phylogenetic analysis based on the complete sequences of the ITS region and partial sequences of large subunit (28S) gene of the nuclear ribosomal RNA demonstrates that the new species is more closely related to the Eurasian species Rhabdias bufonis (Schrank, 1788) than to two other species from sub-Saharan Africa represented in the tree. In addition, partial sequences of the mitochondrial protein coding cox1 and ribosomal 12S genes of the new species have shown significant differences from all previously published sequences of these genes from African species of Rhabdias.

A new species of Centrorhynchus Lühe, 1911 (Acanthocephala: Centrorhynchidae) from the lizard buzzard Kaupifalco monogrammicus (Temminck) (Aves: Accipitridae) in South Africa.

Centrorhynchus sarehae n. sp. is described from the lizard buzzard Kaupifalco monogrammicus (Temminik) in Louis Trichardt City, Limpopo Province, South Africa. The new species can be distinguished from all other species of Centrorhynchus Lühe, 1911 except C. gendrei (Golvan, 1957) and C. mariauxi Smales, 2011 in having a dilated region in the posterior trunk of the female. Centrorhynchus sarehae differs from both these species in the characters of the proboscis armature, particularly the number of hooks per row and the lengths of the longest hooks. This is the first record of a fully identified species of Centrorhynchus in South Africa.

Tissue distribution of perfluoroalkyl acids and health status in wild Mozambique tilapia (Oreochromis mossambicus) from Loskop Dam, Mpumalanga, South Africa.

This study examined concentrations of 15 perfluoroalkyl acids (PFAAs) in tissues from male Mozambique tilapia (Oreochromis mossambicus) collected at Loskop Dam, Mpumalanga, South Africa in 2014 and 2016. Nine of the 15 PFAAs were detected frequently and were included in statistical analysis and included two of the most commonly known PFAAs, perfluorooctanesulfonic acid (PFOS) (median, 41.6ng/g) and perfluorooctanoic acid (PFOA) (median, 0.0825ng/g). Of the tissues measured, plasma (2016 and 2014 median, 22.2ng/g) contained the highest PFAA burden followed by (in descending order): liver (median, 11.6ng/g), kidney (median, 9.04ng/g), spleen (median, 5.92ng/g), adipose (median, 2.54ng/g), and muscle (median, 1.11ng/g). Loskop Dam tilapia have been affected by an inflammatory disease of the adipose tissue known as pansteatitis, so this study also aimed to investigate relationships between PFAA tissue concentrations and incidence of pansteatitis or fish health status. Results revealed that healthy tilapia exhibited an overall higher (p-value<0.05) PFAA burden than pansteatitis-affected tilapia across all tissues. Further analysis showed that organs previously noted in the literature to contain the highest PFAA concentrations, such as kidney, liver, and plasma, were the organs driving the difference in PFAA burden between the two tilapia groups. Care must be taken in the interpretations we draw from not only the results of our study, but also other PFAA measurements made on populations (human and wildlife alike) under differing health status.

Species of Gyrodactylus von Nordmann, 1832 (Platyhelminthes: Monogenea) from cichlids from Zambezi and Limpopo river basins in Zimbabwe and South Africa: evidence for unexplored species richness.

New findings on Gyrodactylus spp. parasitising African cichlids in southern Africa are presented, comprising data from Zimbabwe and South Africa. Morphometry of opisthaptoral hard parts in combination with nuclear ribosomal DNA sequences confirmed the presence of six species of Gyrodactylus von Nordmann, 1832. Three new species are described from fishes in Zimbabwe: Gyrodactylus chitandiri n. sp. from the gill arches of Coptodon rendalli (Boulenger) and Pseudocrenilabrus philander (Weber); Gyrodactylus occupatus n. sp. from the fins of Oreochromis niloticus (L.), Pharyngochromis acuticeps (Steindachner) and P. philander; and Gyrodactylus parisellei n. sp. from the fins of O. niloticus, P. philander and Tilapia sp. Gyrodactylus nyanzae Paperna, 1973 was also identified from the gills of O. niloticus and C. rendalli collected from two localities in Zimbabwe; these findings represent new host and locality records for this parasite. Gyrodactylus sturmbaueri Vanhove, Snoeks, Volckaert & Huyse, 2011 was identified from P. philander collected in South Africa and Zimbabwe thereby providing new host and locality records for this parasite. Finally, Gyrodactylus yacatli García-Vásquez, Hansen, Christison, Bron & Shinn, 2011 was collected from the fins of O. niloticus and P. philander studied in Zimbabwe; this represents the first record of this species from the continent of Africa. Notably, this study improves upon the knowledge of Gyrodactylus spp. parasitising cichlids from these southern African regions. All species studied were recorded from at least two different cichlid host species indicating trend for a wide range of Gyrodactylus hosts in Africa. Accordingly, this supports the idea of intensive host switching in the course of their evolution.

The invasive fish tapeworm Atractolytocestus huronensis (Cestoda), a parasite of carp, colonises Africa.

Biological invasions represent a serious threat for aquaculture because many of introduced parasites may negatively affect the health state of feral and cultured fish. In the present account, the invasive tapeworm Atractolytocestus huronensis Anthony, 1958 (Cestoda: Caryophyllidea), which was originally described from North America and has been introduced to Europe including the British Isles with its specific host, common carp (Cyprinus carpio L.), is reported from Africa for the first time. Its recent introduction to South Africa, where it was found in four localities where common carp is cultured, is another evidence of insufficient prophylactic measures and inadequate veterinary control during transfers of cultured fish, especially common carp, between continents. Together with the Asian fish tapeworm, Bothriocephalus acheilognathi, A. huronensis is another fish tapeworm with ability to spread throughout the globe as a result of man-made introductions of its fish hosts.

Sharptooth catfish shows its metal: a case study of metal contamination at two impoundments in the Olifants River, Limpopo river system, South Africa.

Clarias gariepinus is increasing in importance as a global aquaculture species with a 100 fold increase in production over the past decade but this species still remains one of the most important wild harvested freshwater food fish throughout rural Africa. However, this species has been shown to accumulate metals from contaminated inland waters. In this paper, the metal concentrations in muscle tissue of C. gariepinus from two main-stem impoundments in the Olifants River, Limpopo Basin, were measured and a desktop risk assessment based on the US-EPA methodology completed to evaluate whether long-term consumption of C. gariepinus from these impoundments may pose a health risk to rural communities. Our results show that metals are accumulating in the muscle tissue of C. gariepinus and have appeared to have increased in the last two decades. Risk assessment generated Hazard quotients (HQ) greater than 1 indicate that long term consumption of fish from these impoundments may cause adverse health impacts. We found that lead (HQ=9), antimony (HQ=14), cobalt (HQ=2) and chromium (HQ=1) at one impoundment and lead (HQ=2) at the other impoundment were above acceptable levels for weekly consumption of 150 g C. gariepinus muscle tissue.

Revision of the genus Afrogyrodactylus Paperna, 1968 (Monogenea: Gyrodactylidae) with description of two new species from geographically distant localities.

This study revises the originally monotypic genus Afrogyrodactylus Paperna, 1968 (Monogenea), the species of which infect alestid fish (Characiformes) in Africa, and includes new records of these parasites from three geographically distant countries, Senegal, Sudan and South Africa. Morphology of opisthaptoral hooks and bars and nuclear ribosomal DNA data revealed three Afrogyrodactylus species. Afrogyrodactylus girgifae sp. n. is described from the fins of the Sudanese nurse tetra, Brycinus nurse (Rüppell), and A. kingi sp. n. presents from the gill arches of the South African sharptooth tetra, Micralestes acutidens (Peters), whereas a previously undescribed Afrogyrodactylus sp. occurred on the fins of B. nurse from Senegal. All three species differ conspicuously from the only one known species of this genus, A. characinis Paperna, 1968, by the dimensions of their haptoral hard parts. Detailed morphological and molecular descriptions and comparisons are presented.

Tegumental topography and molecular characterisation of two trematodes (Platyhelminthes: Digenea) from Clarias gariepinus (Burchell, 1822) in Kenya.

The discoveries of new taxonomic features of digenean species through the application of contemporary techniques, such as scanning electron microscopy (SEM) and molecular analysis are still growing. Two species of trematodes Glossidium pedatum and Tylodelphys mashonensis from the intestine and vitreous humour of Clarias gariepinus were recovered from Lake Ol'Bolossat, Kenya. The two endo-helminths were prepared for morphological examination using SEM and molecular characterisation. Additional morphological features were observed for G. pedatum such as domed papillae in the anterior extremity and a protruding cirrus which was unarmed, laterally folded and with a blunt tip as the first such observation for the genus and led to additional characteristics of the diagnosis of the genus. Tylodelphys mashonensis was characterised by a round oral sucker and tribocytic organ rounded with rows of papillae symmetrically arranged. The molecular analyses using ribosomal marker 28S large subunit (LSU) rDNA and mitochondrial (mtDNA) cytochrome c oxidase subunit 1 (cox1) for both G. pedatum and T. mashonensis confirmed the identity of the species and their phylogenetic relationship within the subclass Digenea. This study provides the first mitochondrial (mt)DNA sequence for G. pedatum and also extends the geographical record of two parasites to Kenya.

Dactylogyrus spp. (Dactylogyridae, Monogenea) from tinfoil barb, Barbonymus schwanenfeldii imported into South Africa: morphometric and molecular characterisation.

This study reports on three species of Dactylogyrus Diesing, 1850 (Dactylogyridae) collected from tinfoil barb, Barbonymus schwanenfeldii (Bleeker) which were imported into South Africa as ornamental fish from Sri Lanka and Thailand. Supplementary morphometric characterisation and molecular data (partial 18S and 28S rDNA, and ITS1 region sequences) are presented for Dactylogyrus lampam (Lim & Furtado, 1986), Dactylogyrus tapienensis Chinabut & Lim, 1993 and Dactylogyrus viticulus Chinabut & Lim, 1993. Prevalence of Dactylogyrus spp. infection was 87% and 80% for fish from Sri Lanka and Thailand, respectively. Composition of the parasites between the fish of each origin differed. All three species were found to infect fish from Thailand, but only D. lampam was present on the fish received from Sri Lanka. Phylogenetic analysis revealed the position of studied species, with D. lampam clustering within the lineages of varicorhini-type species, while D. tapienensis and D. viticulus form a sister lineage to Dactylogyrus spp. associated with Cyprinus carpio L. and Carassius spp., species parasitising central African large cyprinids (Labeo Cuvier), and species parasitising African and Middle Eastern Carasobarbus spp.

Title: Dactylogyrus spp. (Dactylogyridae, Monogenea) de Barbonymus schwanenfeldii importé en Afrique du Sud : caractérisation morphométrique et moléculaire. Abstract: Cette étude porte sur trois espèces de Dactylogyrus Diesing, 1850 (Dactylogyridae), prélevées sur des Barbonymus schwanenfeldii (Bleeker) qui ont été importés en Afrique du Sud comme poissons d'ornement depuis le Sri Lanka et la Thaïlande. Une caractérisation morphométrique et des données moléculaires supplémentaires (ADNr 18S et 28S partiels et séquences de la région ITS1) sont présentées pour Dactylogyrus lampam (Lim & Furtado, 1986), Dactylogyrus tapienensis Chinabut & Lim, 1993 et Dactylogyrus viticulus Chinabut & Lim, 1993. La prévalence de l'infection par les Dactylogyrus spp. était respectivement de 87 % et 80 % pour les poissons du Sri Lanka et de Thaïlande. La composition des parasites entre les poissons des deux origines différait. Les trois espèces infectaient les poissons de Thaïlande, mais seul D. lampam était présent sur les poissons du Sri Lanka. L'analyse phylogénétique a révélé la position des espèces étudiées, D. lampam se regroupant dans les lignées d'espèces de type varicorhini, tandis que D. tapienensis et D. viticulus forment une lignée sœur des Dactylogyrus spp. associés à Cyprinus carpio L. et Carassius spp., espèces parasitant les grands cyprinidés d'Afrique centrale (Labeo Cuvier), et espèces parasitant les Carasobarbus spp. d'Afrique et du Moyen-Orient.