| Description |
In 2018, my research activities continue to investigate the diversity of dactylogyrids parasitizing African tetras. Herein, the most important results are briefly summarized. Morphological and molecular characterizations of seven (three new) species of Characidotrema (C. auritum n. sp., C. brevipenis, C. nursei, C. pollex n. sp., C. spinivaginus, C. vespertilio n. sp., and C. zelotes) from Brycinus nurse and B. imberi have been provided [1]. Morphological analysis confirmed that the most apparent character distinguishing species in the genus is morphology of the male copulatory organ and vagina. Observations on the haptoral sclerotized structures of these parasites by employing phase contrast microscopy revealed the presence of an accessory structure relating to the ventral anchor, a feature that improves generic diagnosis of Characidotrema. Phylogenetic analyses based on 28S rDNA sequences supported the monophyly of Characidotrema spp., and indicated a closer relationship of this genus to monogeneans parasitizing African cyprinids (Dactylogyrus spp.) and cichlids (species of Cichlidogyrus, Scutogyrus, and Onchobdella) rather than to those parasitizing catfishes (species of Quadriacanthus, Schilbetrema, and Synodontella). The overall agreement between the morphological diversification of the MCOs and molecular tree observed in our study indicates that significant phylogenetic signals for clarifying relationships among species of Characidotrema are present in characteristics of the MCO. Morphological and molecular evaluation of 16 species of Annulotrema collected from nine species of African tetras (Alestes baremoze, A. dentex, Brycinus imberi, B. nurse, Hydrocynus forskahlii, H. brevis, H. vittatus, Micralestes acutidens, and M. elongatus) revealed the presence of nine undescribed species. The obtained molecular data will be used for phylogenetic reconstruction of monogeneans parasitizing African tetras. Finally, preliminary phylogenetic analyses of monogeneans parasitizing alestids showed that Afrocleidodiscus hydrocynuous from Hydrocynus forskahlii and representatives of Annulotrema clustered together, while A. paracleidodiscus from Distichodus rostratus (Characiformes: Distichodontidae) forms separate cluster close to the Characidotrema species. Division of the both species of Afrocleidodiscus highlights the necessity of a revision of the genus [2].
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