Morphology Data of Petrocephalus longianalis
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: Number of anal fin rays between 30 and 35; anal fin length 24.4-27.8% of standard length; preanal length 54.3-59.0% of standard length (Ref. 91771). Caudal peduncle depth 26.9-33.1% of its length (Ref. 91771).

Description: Body long-oval shape (Ref. 91771). Head broadly rounded 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, obliquely orientated, anteriorly higher and posteriorly lower, distal margin crescentic with anterior two or three rays longer than posterior rays, and number of rays 22-25. 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, number of rays 30-35 (Ref. 91771). Scales cycloid with reticulate striae, scales extending anteriorly to operculum and pectoral fins; scales in lateral series 39-42; scales on caudal peduncle circumference, 11-12 (Ref. 91771). Caudal peduncle slender, subcylindrical entire length, between 18.4-19.9% of standard length (Ref. 91771).

Colour: In preservation: Body brown, back only slightly darker, breast and belly fair, fins rather unpigmented and transparent, anal and dorsal fin bases emphasized as dark lines (Ref. 91771). A well-circumscribed dark spot below dorsal fin origin, except for some specimens (Ref. 91771).

Ease of Identification

Meristic characteristics of Petrocephalus longianalis

Lateral Lines Interrupted: No
Scales on lateral line 39 - 42
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line
Scale rows below lateral line
Scales around caudal peduncle 11 - 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 22 - 26
Adipose fin absent

Caudal fin


Anal fin(s)

Fins number 1
Spines total 0 - 0
Soft-rays total 30 - 35

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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