Main characters of the suborder concern the infraorbital bones, a series of dermal bones below the orbit: The infraorbital 2 in all notopterids is medium sized and subrectangular in shape. The infraorbital 3 also is short, subrectangular, posteriorly deep and fan-like (it is lacking in the genus Notopterus ). All notopteroids have a prominent lateral extension of the orbital margin of both infraorbital 1 and 2, an »infraorbital ledge«, (not to be confused with the »subocular shelf«, an inward extension of the bony lamina from infraorbitals) as found in the majority of the teleosts. The infraorbital canal on infraorbital 1 to 3 is an open groove; a condition »not seen in any of the basal teleosts including elopomorphs or the other osteoglossomorphs«, though convergent in some primitive euteleosts (Li and Wilson, 1996). Finally there is a distinctive character realised in the stato-acoustic organ. A most peculiar feature is the complete separation of utriculus and sacculus of the statoacoustic organ. In mormyrids sacculus and lagena are tightly connected to a vesicle of the swimbladder; notopterids do not have such a vesicle, but they have a very large saccular otolith with a handle-like prolongation (Greenwood, 1973, Lauder and Liem, 1983), a condition never met with in any other extant bony fish.
This suborder consists of three families:
Family Mormyridae , with about 200 species.
Family Notopteridae , with only 8 species.
Family Gymnarchidae , with only one species Gymnarchus niloticus .