Three species of cichlid fish, Tilapia brevimanus Boulenger, 1911, T. buttikoferi (Hubrecht, 1881), and T. cessiana Thys van den Audenaerde, 1968, from Guinea, Ivory Coast and Sierra Leone (West Africa) were examined for gill parasites for the first time. Six species of Monogenea were found of which one, Cichlidogyrus digitatus Dossou, 1982, had been previously described. Five new species, all belonging to the genus Cichlidogyrus Papema, 1960, are described herein: C. albareli sp. n., C. hemi sp. n., C. nuniezi sp. n„ C. honhommei sp. n., and C. slembroucki sp.n.
Tilapia cabrae Boulenger, 1899, a cichlid fish from coastal lowlands of the Republic of Congo (Africa), was examined for gill parasites. Four new species of the Monogenea were found, all belonging to Cichlidogyrus (Ancyrocephalidae): C. berradae sp. n., C. revesati sp. n., C. legendrei sp. n., and C. lemoallei sp. n. A possible relationship between the relative size of haptoral sclerites (i.e., uncinuli compared to gripi) and microhabitat selection in the studied host-parasite model is discussed.
Lamellodiscus dentexi Aljoshkina, 1984, a gill parasite of Dentex macrophthalmus (Bloch), is redescribed based on new material from the northwest coast of Africa (Senegal and Morocco). Three new species of Lamellodiscus Johnston et Tiegs, 1922 from D. macrophthalmus are described, Lamellodiscus toguebayei sp. n., L. vicinus sp. n., and L. triacies sp. n., all belonging to the ''ignoratus'' group. They can be distinguished from all other species of this group by the size and shape of male copulatory organ and sclerotised parts of the haptor. Considering the peculiar morphology of the male copulatory organ (long and thin tube) we propose to put together L. dentexi, L. virgula Euzet et Oliver, 1967 and L. obeliae Oliver, 1973 to form the ''elongatus'' type within the ''elegans'' group.