A SYSTEMATIC REVISION OF THE LARGE-SCALED MARCUSENIUS WITH DESCRIPTION OF A NEW SPECIES FROM CAMEROON (TELEOSTEI-OSTEOGLOSSOMORPHA MORMYRIDAE)

Nine out of 37 recognized species in the genus Marcusenius have eight large circumpeduncular scales rather than 12 or 16, which is more typi cal of the genus. They are: M. dundoensis, M. fuscus, M. ghesquierei, M. intermedius, M. kutuensis, M. lambouri, M. moorii, M. paucisquamatu s and M. schilthuisiae. All nine are restricted to West-Central and Ce ntral Africa. A detailed morphometric analysis could not distinguish d ifferences between M. moorii, M. paucisquamatus and M. lambouri. There fore they are considered as synonyms with M. moorii as the senior syno nym. The systematic status of M. intermedius is uncertain owing to the existence of only three specimens. Within this species complex a new species, Marcusenius sanagaensis, is described from the Sanaga River b asin in Cameroon. It differs from all the others in the number of scal es on the lateral line and in the extent of the broad dark band betwee n the anterior base of the dorsal fin and the anterior base of the ana l fin. All valid Marcusenius species with eight circumpeduncular scale s are redescribed and a key to these species is given.