The Mayfly-Mussel Association, a New Example from the River Niger Basin

Abstract

A new genus and species, Mutelocloeon bihoumi , of Baetidae associated with freshwater mussels (Mutelidae), is described from nymphs collected in rivers in Mali and Guinea, West Africa. A description is also given of the adult, based on material from light-trap catches made at the same sites as the nymphal captures and on the morphology of mature nymphs. It is shown that Centroptilum corbeti Kimmins, described from adults collected in Uganda, should be transferred to Mutelocloeon . Mayfly nymphs were found sporadically in several species of mutelid mussels occurring in sandy rivers, and it was concluded that the ecology of the mussel was the main factor regulating the association. Nymphs are attached to the folds of the branchiae within the mantle cavity. Individual mussels contained up to five nymphs.