Morphology Data of Petrocephalus okavangensis
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 always different morphology between mature adults
Different colors
Remarks Males with kink in anal fin base which is absent in juveniles and females where the anal fin base is straight (Ref. 91771).

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 26.1-34.8% of standard length; head length 23.2-27.4% of standard length; preanal length 53.8-61.9% of standard length; dorsal fin length 14.5-19.5% of standard length; length of anal fin 24.7-28.6% of standard length; depth of caudal peduncle 26.4-34.9% of its length; number of anal fin rays 27-32; number of scales in lateral line row 37-38; number of scales around caudal peduncle 12 (Ref. 91771).

Description: Body oval shape; head with distinctly pointed nose in most specimens, with a 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, oblique 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, 27-32 anal fin rays (Ref. 91771). Scales cycloid with reticulate striae, scales extending anteriorly to operculum and pectoral fins; scales in lateral series 37-38; scales on caudal peduncle circumference, 12 (Ref. 91771). Caudal peduncle slender, subcylindrical entire length, usually 18.2-23.0% of standard length (Ref. 91771).

Colour: In life grey-silver or brownish-silver, then with gold-olive hue, anal fin base emphasized by black line, less distinct for dorsal fin base, first few rays of unpaired fins darker, irregular shaped dark spot under dorsal fin origin, sometimes vivible only on one body side, throat and belly very fair, back dark, paired fins light and transparent (Ref. 91771). In preservation between ochre and light brown; for some preserved specimens the dark spot below dorsal fin seems to have faded (Ref. 91771).

Ease of Identification

Meristic characteristics of Petrocephalus okavangensis

Lateral Lines Interrupted: No
Scales on lateral line 37 - 38
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line
Scale rows below lateral line
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 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 27 - 32

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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