Morphology Data of Petrocephalus magnoculis
Identification keys
Main Ref. Kramer, B., R. Bills, P. Skelton and M. Wink, 2012
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
Type of scales cycloid scales

Diagnosis: Body depth 28.3-34.0% of standard length; head length 25.0-27.7% of standard length; preanal length 59.0-62.8% of standard length; anal fin length 21.5-25.6% of standard length; diameter defined by orbital rims 25.9-32.9% of head length; length of snout to posterior orbital rim of eye 47.0-51.4% of head length; length of snout to centre of eye 35.2-39.1% of head length; number of dorsal fin rays 20-24; number of scales in lateral line row 38-42 (Ref. 91771).

Description: Body oval shape; head with rounded nose, small ventrally positioned subterminal mouth, situated ventral to the eye; head and body dorsolaterally compressed (Ref. 91771). Dorsal fin origin situated about two-thirds of standard length from snout, obliquely orientated, anteriorly higher and posteriorly lower, distal margin crescentic with anterior two or three rays longer than posterior rays, 20-24 dorsal fin rays (Ref. 91771). Anal fin longer than dorsal fin, opposite dorsal fin with slightly more anterior origin, obliquely orientated, anteriorly lower and posteriorly higher, anterior 10 or so rays longer than posterior ones, especially in males where they also appear stronger, margin broadly rounded, rays posterior to first 10 with distal margin straight, 26-31 anal fin rays (Ref. 91771). Scales cycloid with reticulate striae, scales extending anteriorly to operculum and pectoral fins; scales in lateral series 38-42; scales on caudal peduncle circumference, 11-13 (Ref. 91771). Caudal peduncle slender, subcylindrical entire length, usually 18.4-21.8% of standard length (Ref. 91771).

Colour: In life, it is grey-silver, with underside lighter, paired fins light and transparent (Ref. 91771). In preservation, it is light beige, back darker and grey, but brown where mormyrid skin is gone (Ref. 91771).

Ease of Identification

Meristic characteristics of Petrocephalus magnoculis

Lateral Lines Interrupted: No
Scales on lateral line 38 - 42
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line
Scale rows below lateral line
Scales around caudal peduncle 11 - 13
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 0 - 0
Soft-rays total 20 - 24
Adipose fin absent

Caudal fin


Anal fin(s)

Fins number 1
Spines total 0 - 0
Soft-rays total 26 - 31

Paired fins

Pectoral Attributes  
Pelvics Attributes  
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Boden, Gert
Modified by Bailly, Nicolas
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