Species of Alestidae are known to be parasitised by dactylogyrid monogeneans representing three genera, Afrocleidodiscus Paperna, 1969, Annulotrema Paperna & Thurston, 1969, and Characidotrema Paperna & Thurston, 1968. The objective of the present study was to investigate the species diversity of Monopisthocotylea of African tetras from the Lower Phongolo River and floodplain in South Africa. Four new and two previously described species of Annulotrema were identified from the gills of three species of African tetras, Brycinus imberi, Hydrocynus vittatus, and Micralestes acutidens. The collected parasites were studied using two complementary approaches: morphology of hard sclerotised structures, and molecular markers using rDNA sequence data (28S rDNA, 18S rDNA, and ITS1). Three new species, Annulotrema arcum n. sp., Annulotrema caputfemoris n. sp., and Annulotrema strepsiceros n. sp., were described from B. imberi and one species, Annulotrema retortum n. sp., from M. acuditens. Two previously described species, Annulotrema pikoides Guégan, Lambert and Birgi, 1988 and A. pseudonili Kičinjaová and Řehulková, 2017, were newly recorded from H. vittatus in South Africa. Annulotrema arcum n. sp. and A. caputfemoris n. sp. share similar male copulatory organ morphologies, suggesting a close phylogenetic relationship as sister taxa. Despite weak nodal support, A. strepsiceros n. sp. shows morphological congruence with the former two species, reinforcing their molecular linkage. The present study shows a critical need for the exploration of monopisthocotylean diversity and the paucity of available molecular data of representatives from this group.

TITLE: Espèces d'Annulotrema (Monopisthocotylea, Dactylogyridae) parasitant des tétras africains (Characiformes, Alestidae) dans la rivière Phongolo, en Afrique du Sud, avec description de quatre nouvelles espèces. ABSTRACT: Les espèces d'Alestidae sont connues pour être parasitées par des monogènes Dactylogyridae représentant trois genres, Afrocleidodiscus Paperna, 1969, Annulotrema Paperna & Thurston, 1969 et Characidotrema Paperna & Thurston, 1968. L'objectif de la présente étude était d'examiner la diversité des espèces de Monopisthocotylea des tétras africains du cours inférieur de la rivière Phongolo et de sa plaine inondable en Afrique du Sud. Quatre nouvelles espèces d'Annulotrema et deux espèces déjà décrites ont été identifiées à partir des branchies de trois espèces de tétras africains, Brycinus imberi, Hydrocynus vittatus et Micralestes acutidens. Les parasites collectés ont été étudiés en utilisant deux approches complémentaires, la morphologie des structures sclérifiées et les marqueurs moléculaires utilisant des données de séquence d'ADNr (ADNr 28S, ADNr 18S et ITS1). Trois nouvelles espèces, Annulotrema arcum n. sp., Annulotrema caputfemoris n. sp. et Annulotrema strepsiceros n. sp., ont été décrites chez B. imberi et une espèce, Annulotrema retortum n. sp., chez M. acuditens. Deux espèces précédemment décrites, Annulotrema pikoides Guégan, Lambert et Birgi, 1988 et A. pseudonili Kičinjaová et Řehulková, 2017, ont été nouvellement répertoriées chez H. vittatus en Afrique du Sud. Annulotrema arcum n. sp. et A. caputfemoris n. sp. partagent des morphologies similaires de l’organe copulateur mâle, suggérant une relation phylogénétique étroite de taxons frères. Malgré un faible support nodal, A. strepsiceros n. sp. présente une congruence morphologique avec les deux premières espèces, renforçant leur lien moléculaire. La présente étude montre qu'il est essentiel d'explorer la diversité des Monopisthocotylea et que les données moléculaires disponibles sur les représentants de ce groupe sont rares.

• Keywords
• 28S rDNA, Alestidae, Annulotrema, Monogenea, South Africa,
• MeSH
• Characiformes * parasitology   MeSH
• DNA, Helminth MeSH
• Phylogeny * MeSH
• Trematode Infections * veterinary   parasitology   MeSH
• DNA, Ribosomal Spacer genetics   MeSH
• Fish Diseases * parasitology   MeSH
• Platyhelminths classification   anatomy & histology   genetics   isolation & purification   MeSH
• Rivers * MeSH
• DNA, Ribosomal MeSH
• RNA, Ribosomal, 18S genetics   MeSH
• RNA, Ribosomal, 28S genetics   MeSH
• Trematoda * classification   anatomy & histology   genetics   isolation & purification   MeSH
• Gills * parasitology   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• South Africa MeSH
• Names of Substances
• DNA, Helminth MeSH
• DNA, Ribosomal Spacer MeSH
• DNA, Ribosomal MeSH
• RNA, Ribosomal, 18S MeSH
• RNA, Ribosomal, 28S MeSH

BACKGROUND: African tetras (Alestidae) belonging to Brycinus Valenciennes are known to be parasitized with monogeneans attributed to two genera, Annulotrema Paperna & Thurston, 1969 and Characidotrema Paperna & Thurston, 1968 (Dactylogyridae). During a survey of monogeneans parasitizing alestids, species of Characidotrema were collected in Cameroon, D. R. Congo, Senegal, South Africa, Sudan and Zimbabwe. This paper provides new morphological data and the first molecular analysis broadening our knowledge on the diversity of these parasites. RESULTS: Seven species (four known and three new) of Characidotrema are reported from two species of Brycinus: C. auritum n. sp. and C. vespertilio n. sp. from B. imberi (Peters); and C. brevipenis Paperna, 1969, C. nursei Ergens, 1973, C. pollex n. sp., C. spinivaginus (Paperna, 1973) and C. zelotes Kritsky, Kulo & Boeger, 1987 from B. nurse (Rüppell). Species identification was based on morphological analysis of the sclerotized structures supported by nuclear ribosomal DNA (partial 18S rDNA, ITS1, and 28S rDNA) sequence data. Morphological analysis confirmed that the most apparent character distinguishing species in the genus is the morphology of the male copulatory organ and vagina. Observations on the haptoral sclerotized elements of these parasites by means of phase contrast microscopy revealed the presence of a sheath-like structure relating to the ventral anchor, a feature that supplements the generic diagnosis of Characidotrema. Maximum Likelihood and Bayesian analyses of the large subunit (28S) rDNA sequences recovered Characidotrema species isolated from the two Brycinus hosts as monophyletic, and indicated a closer relationship of this group to monogeneans parasitizing African cyprinids (Dactylogyrus spp.) and cichlids (species of Cichlidogyrus Paperna, 1960, Scutogyrus Pariselle & Euzet, 1995, and Onchobdella Paperna, 1968) than to those from catfishes (species of Quadriacanthus Paperna, 1961, Schilbetrema Paperna & Thurston, 1968 and Synodontella Dossou & Euzet, 1993). The overall agreement between the morphological diversification of the MCOs and the molecular tree observed in this study indicates that significant phylogenetic signals for clarifying relationships among species of Characidotrema are present in the characteristics of the MCO. CONCLUSIONS: It seems that intra-host speciation is an important force shaping the present distribution and diversity of Characidotrema but further studies are necessary to confirm this hypothesis and assess questions related to the phylogeny of these parasites. To identify potential co-speciation events, co-phylogenetic analyses of these monogeneans and their alestid hosts are required.

• Keywords
• Africa, Alestidae, Brycinus, Characidotrema, DNA, Dactylogyridae, Diversity, Monogenea,
• MeSH
• Cichlids parasitology   MeSH
• Phylogeny * MeSH
• Host-Parasite Interactions * MeSH
• Lakes parasitology   MeSH
• Fish Diseases parasitology   MeSH
• DNA, Ribosomal genetics   MeSH
• Trematoda classification   isolation & purification   MeSH
• Gills parasitology   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Africa South of the Sahara MeSH
• Names of Substances
• DNA, Ribosomal MeSH