Morphological characterisation of gill monogeneans (Monogenea: Dactylogyridae) of Enteromius aspilus Boulenger, 1907 and Enteromius guirali Thominot,1886 captured in the Cesala River, Cameroon 

Monogeneans are fish ectoparasites which infested commonly gill filament. They are characterised by their sclerotized haptoral and genital structures. Morphological study of gill monogeneans was conducted at Lebamzip, Center Region of Cameroon. Fish were caught along Cesala River using fishing rods or gillnets, kept in icebox and transported to the laboratory of parasitology and ecology at University of Yaoundé I. Each monogenean was mounted between slide and coverslip in a drop of GAP mixture. Drawings of the sclerotized structures were made using Corel Draw and measurements were taken on Amscope. Four monogeneans species belonging to the genus Dactylogyrus were inventoried. One new species is described ( D. cesalaensis n. sp. from E. aspilus ) and three described species as follows: D. aspili from E. aspilus ; D. mendehei and D. nyongensis from E. guirali are rediscribed. Each monogenean species presented a filamentous anchor and MCO with a flame type accessory piece. Particularly, D. cesalaensis n. sp. have dorsal bar W-shaped; filamentous hooks; vagina shaped like a dagger blade. For D. aspilus : dorsal bar V-shaped; pair I of hooks most developed without filament; pairs II-VII are filamentous; vagina is a leaf-like piece with spiny ends. Concerning D. mendehei : pair I of hooks without filament; pairs II-VII are filamentous; dorsal bar U-shaped. For D. nyongensis : dorsal bar arched; filamentous hooks; three forms of MCO belonging to the flame type observed; vagina comma-shaped. All encountered monogeneans are classed in the Dactylogyrus wunderi type. Colonisation-extinction phenomena explained the parasitic richness observed during this study.