From Lavoué and Sullivan (2014):
Body ovoid, 2.7 times longer than high and laterally compressed. Head length 3.3 times in standard length. Snout short (HL/ SNL = 6.6) and round. Mouth small (HL/MW = 4.4), subterminal, opening under ante- rior half of eye. Teeth small and bicuspid, 13 in single row in upper jaw, 24 in single row in lower jaw. Nostrils closely set (distance between nostrils = 0.4 mm) with the posterior one very close to eye (distance between posterior nostril and eye = 0.1 mm). Dorsal and anal fins originating in posterior half of body (SL/PDD = 1.6 and SL/PAD = 1.8). Pre- dorsal distance slightly greater than pre-anal distance (PDD/PAD = 1.1). Dorsal fin with 23 branched rays. Anal fin with 34 branched rays. Pectoral fins with 9 rays. Pelvic fin with 6 rays. Distance between pelvic fin and anal fin = 10.1 mm. Distance between pec- toral fin and anal fin = 16.4 mm. Scales cover body, except for head. Lateral line visible and complete with 34 pored scales along its length. Ten scales around caudal peduncle. Ten scales between anterior base of anal fin and lateral line. Caudal peduncle narrow (CPL/CPD = 1.6). Thick skin on head. Knollenorgans visible, clustered into two distinct rosettes, Nackenrosette and Kehlrosettes as described in Harder (1968). Knollenorgan pores in front of eye not highly condensed in the form of a discernable Augenrosette.
From Lavoué and Sullivan (2014):
Petrocephalus boboto sp. n. is distinguished from all other Petrocephalus species of Central Africa (i.e., Lower Guinea and Congo provinces) by the following combination of characteristics: three distinctive bilateral black spots on body, one at origin of the pectoral fin, one at origin of caudal fin and one on flank just below ante- rior part of dorsal fin; two distinct electoreceptive rosettes in head (i.e., Nakenrosette and Khelrosette), the third rosette (Augenrosette) reduced in size to few knollenorgan pores; 23 branched rays in dorsal fin and 34 branched rays in anal fin; triphasic EOD waveform of normal polarity (i.e. first phase head-positive).
Standard length = 56.9 mm.