Petrocephalus, FROM

Lavoué, Sébastien, Hopkins, Carl D. & Toham, André Kamdem, 2004, The Petrocephalus (Pisces, Osteoglossomorpha, Mormyridae) of Gabon, Central Africa, with the description of a new species, Zoosystema 26 (3), pp. 511-535 : 531-532

KEY TO THE SPECIES OF PETROCEPHALUS FROM GABON

1. Distinct sub-dorsal black spot present, wide mouth; more than 25 teeth in the lower jaw; width between 2.7 and 3.9 times in head length .................................. P. balayi

— Sub-dorsal black spot absent; fewer than 25 teeth in the lower jaw; narrow mouth, width at least 3.6 times in head length.................................................................... 2 2. 15 to 18 branched rays in the dorsal fin; 8 to 10 scales between the origin of the anal fin and the lateral line; small eye, diameter at least 4.1 times in head length .............. ...................................................................................................... P. microphthalmus

— More than 18 branched rays on the dorsal fin, rarely 18; more than 10 scales between the origin of the anal fin and the lateral line, diameter of the eye at most 4.1 times in head length ........................................................................................ 3

3. Mouth posteriorly-positioned; opening below the posterior half of the eye; distance between the anterior extremity of the snout and the corner of the mouth at least 3.8 times (average 4.7) in head length; 14 to 20 (average 17) scale rows between the anterior base of the anal fin and the lateral line; EOD possesses a third positive phase.............................................................................................. P. sullivani n. sp.

— Mouth in sub-terminal position, slightly lower-positioned; opening under the anterior half of the eye; distance between the anterior extremity of the snout and the corner of the mouth at most 4.4 (average 3.2) times in head length, 10 to 16 (average 14) scales rows between the anterior base of the anal fin and the lateral line; EOD lacks a third positive phase ................................................................ P. simus