Morphology Data of Mastacembelus nigromarginatus
Identification keys
Main Ref. Vreven, E.J., 2003
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 eel-like
Cross section
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth
Type of scales

Diagnosis: no pre-opercular spines; 27+1 up to 31+1 (median 29+1) dorsal spines; distance from anterior border of snout to last externally visible dorsal spine 49.7-57.6% SL (m=54.2), increasing with size; distance from posterior edge of pectoral fin to anterior origin of 1st dorsal spine between (-21.7) and 0.0% HL [m = -11.8]; pre-orbital spine as good as always present; snout with a more pointed appearance; origin of 1st dorsal spine situated anterior to, or below, posterior edge of pectoral fin; distance from anterior border of snout to last externally visible dorsal spine 50.0-57.6% SL (m=54.1), shorter than distance from anterior border of snout to last externally visible anal spine, 54.2-62% SL (m=58.3), both decreasing in percentages with increasing size; post-anal length 43.5-51.0% SL (m=46.3) increasing with size, shorter than pre-anal length, 48.3-55.1% SL (m=52.5) and decreasing with size, becoming equal to latter with increasing size; 9-12 caudal fin rays; 4-6 predorsal vertebrae; 35-40 abdominal vertebrae; (+4)-(+5) in-between vertebrae; 53-60 caudal vertebrae (Ref. 57415).

Coloration: light brown overall background colour; lateral sides characterized by a more or less pronounced dark brown battlement pattern, which forms a well delimited edge between dark lateral sides and lighter colour dorsal sides and dorsal midline; nevertheless, dorsal midline often with a series of dark brown saddle-like blotches; ventral side of head, belly and abdomen white, yellowish of colour but not so well delimited from lower sides; lower sides with irregularly shaped, white, yellowish spots; background colour of dorsal caudal and anal fins white, transparent, mottled scarcely with small, round, brown spots; dorsal and anal fin base with a series of dark brown, round spots partially situated, respectively, on dorsal and ventral part of tail; often those spots not independent but connected with dark brown-coloured tail and can even be interpreted as an enlargement of tail colour pattern on basal part of fins; on the more distal part of dorsal and anal fins additional small dark brown spots can be observed; pectoral fins white, yellowish of overall background colour with small light brown spots and a brown base; colour pattern changes with size, especially darkening of unpaired fins; nevertheless, outermost margin of dorsal, caudal and anal fins always remains white; in addition, small dark brown spots situated on more distal part of median fins, gradually with increasing size, form a continuous broad, black band on these fins; on anal fin this band is often connected with ventral side of tail due to an enlargement of the spots situated on base of fin resulting in a series of yellowish, white spots on base of anal fin; on dorsal fin both remain separate; upper edge of lateral dark brown band with its battlement pattern becomes less contrasted or may even disappear (Ref. 57415).

Ease of Identification

Meristic characteristics of Mastacembelus nigromarginatus

Lateral Lines Interrupted: No
Scales on lateral line
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line
Scale rows below lateral line
Scales around caudal peduncle
Barbels 0
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
total 91 - 98


Dorsal fin(s)

Attributes continuous with caudal fin
Fins number 1
Finlets No. Dorsal   0
Ventral  0
Spines total 28 - 32
Soft-rays total 82 - 104
Adipose fin absent

Caudal fin

Attributes confluent

Anal fin(s)

Fins number 1
Spines total
Soft-rays total 75 - 94

Paired fins

Pectoral Attributes  
Pelvics Attributes  suppressed/absent
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Boden, Gert
Modified by Musschoot, Tobias
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