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Diagnosis: Petrocephalus boboto is distinguished from all other Petrocephalus species of Central Africa 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 anterior part of dorsal fin; two distinct electroreceptive rosettes in head, the third rosette reduced in size to few knollenorgan pores; 23 branched rays in dorsal fin and 34 branched rays in anal fin; and triphasic EOD waveform of normal polarity (Ref. 96601).
Description: Body ovoid, 2.7 times longer than high and laterally compressed (Ref. 96601). Head length 3.3 times in standard length; snout short and round, ratio head length and snout length 6.6 (Ref. 96601). Mouth small, ratio of head length and mouth width 4.4; subterminal, opening under anterior half of eye (Ref. 96601). Teeth small and bicuspid, 13 in single row in upper jaw, 24 in single row in lower jaw (Ref. 96601). Nostrils closely set, the distance between nostrils 0.4 mm, with the posterior one very close to eye, the distance between posterior nostril and eye 0.1 mm (Ref. 96601). Caudal peduncle narrow, ratio lenght/height 1.6 (Ref. 96601). Dorsal and anal fins originating in posterior half of body; predorsal distance slightly greater than pre-anal distance; dorsal fin with 23 branched rays; anal fin with 34 branched rays; pectoral fins with 9 rays; distance between pelvic and anal fin 10.1 mm; distance between pectoral fin and anal fin 16.4 mm (Ref. 96601). 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 (Ref. 96601). Thick skin on head; knollenorgans visible, clustered into two distinct rosettes; knollenorgan pores in front of eye not highly condensed in the form of a discernable Augenrosette (Ref. 96601).
Colouration: Body background colour uniformly gray/silver with metallic reflection on the flanks and head; light melanophores densely and evenly distributed on body, slightly larger on head; three distinct black marks on each side of the body, one at the base of the pectoral fins, one at the base of the caudal fin and one subdorsal, below the first anterior rays of the dorsal fin; all fins hyaline (Ref. 96601). Preserved colouration: background beige with dorsum slightly darker; numerous light melanophores visible all over body; thick skin on head and fins opaque; three distinct melanin marks on side of body distinctly visible (Ref. 96601). |