Morphology Data of Petrocephalus odzalaensis
Identification keys
Main Ref. Lavoué, S., J.P. Sullivan and M.E. Arnegard, 2010
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance
Different colors

Descriptive characteristics of juvenile and adult

Striking features
Body shape lateral fusiform / normal
Cross section
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth sub-terminal/inferior
Type of scales cycloid scales

Diagnosis: Petrocephalus odzalaensis is distinguished from all other Petrocephalus species in Central Africa by the following combination of characteristics: dorsal fin shorter than anal fin; dorsal fin with a maximum of 22 branched rays; anal fin with a minimum of 27 branched rays; mouth sub-terminal, ratio between head length and mouth position is between 4,2 and 5,0; and eye small, the ratio head length and eye-diameter between 3,7 and 4,2 (Ref. 85331). Body pinkish-gray, darker dorsally, with the presence of three distinct pigmentation patches: (1) a distinct ovoid black mark situated below the anterior base of the dorsal fin on each side of the body; (2) a small black mark at the base of each pectoral fin; (3) an ovoid black mark on each side that is centered at the base of the caudal fin, not extending onto the upper and lower lobes of this fin (Ref. 85331).

Description: Body ovoid, longer than high, the ratio standard length and height between 2.6 and 2.9, and laterally compressed (Ref. 85331). Head length between 3.7 and 4.0 times in standard length (Ref. 85331). Snout short, the ratio head length and snout length between 6.2 and 8.3, and round (Ref. 85331). Mouth small, the ration head length and mouth width between 4.0 and 4.8, subterminal, opening just under the anterior half of the eye (Ref. 85331). Teeth small and bicuspid, 8-12 in a single row in the upper jaw, 18-23 in a single row in the lower jaw (Ref. 85331). Caudal peduncle thin, the ration caudal peduncle length and caudal peduncle depth between 1,9 and 2,3 (Ref. 85331). Dorsal and anal fins originate in the posterior half of the body; pre-dorsal distance slightly greater than the pre-anal distance; dorsal fin with 20-22 branched rays; anal fin with 27-29 branched rays (Ref. 85331). Scales cover the body, except for the head; lateral line visible and complete with 36-38 pored scales along its length; 10-14 scales between the anterior base of the anal fin and the lateral line; 12 scales around the caudal peduncle (Ref. 85331). Skin on head thick, turning opaque with formalin fixation; knollenorgans clustered into three distinct rosettes (Ref. 85331).

Colouration: Body background colour pinkish-gray, darker dorsally; pigmentation pattern consisting of three characteristic black patches: a distinct ovoid black mark below the anterior base of the dorsal fin; a small black mark at the base of the pectoral fin; and an ovoid black mark centered at the base of the caudal fin, which does not extend onto the upper and lower lobes; fins translucent (Ref. 85331).

Ease of Identification

Meristic characteristics of Petrocephalus odzalaensis

Lateral Lines Interrupted: No
Scales on lateral line 36 - 38
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line
Scale rows below lateral line 10 - 14
Scales around caudal peduncle 12 - 12
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb


Dorsal fin(s)

Attributes no striking attributes
Fins number 1
Finlets No. Dorsal   
Spines total
Soft-rays total
Adipose fin absent

Caudal fin

Attributes forked; more or less normal

Anal fin(s)

Fins number 1
Spines total
Soft-rays total

Paired fins

Pectoral Attributes  more or less normal
Pelvics Attributes  more or less normal
Position    abdominal  before origin of D1
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Boden, Gert
Modified by Bailly, Nicolas
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