Mormyrops nigricans Boulenger 1899

Body depth 4.1–5.5 times into SL, greatest near pelvic fins. Length of head, 3.2–3.6 times into SL. Head depth 52–54% of its length. Upper and lower profile of head concave. Snout rounded, mouth terminal. Snout length 6.4–6.8% SL, 17–24% HL. Mouth width 80–83% of snout length. Chin reduced. Teeth truncate, 21–27 in upper jaw, 25–33 in lower, arranged in a single, even row on entire margin of each jaw. Eye small, its diameter 25–46% of the interorbital width. Interorbital width 54–57% of head width. Dorsal fin with 24–25 rays, its length 17–18% SL. Anal 38–41, its length 28–29% SL, 1.5–1.6 times anal length. Preanal to predorsal ratio, 0.88–0.92. Pectoral fin rounded, not reaching pelvics. Pelvic fins closer to pectorals than to anal. Caudal fin small, rounded lobes. Caudal peduncle short, its length 5.8–7.8% SL, but deep, 1.2–1.6 times as long as deep. Twelve circumpeduncular scales. Lateral line 53–58 scales.

Color: dark grey-violet with dark mottling and irregular spots, lighter on underbelly. Dark longitudinal lines across the middle of many scales on the flank.