Morphology Data of Malapterurus stiassnyae
Identification keys
Main Ref. Norris, S.M., 2002
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 elongated
Cross section circular
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth
Type of scales

Diagnosis: body elongate and cylindrical; tooth patches narrow; vertically based pectoral fins positioned at the body mid-depth; 8-11 anal-fin rays; usually more than 17 gill rakers on first arch; 2 ventral unbranched and 7-8 branched caudal-fin rays; 8-11 pectoral-fin rays; caudal saddle and bar pattern well developed in juveniles and young; caudal fin darkly pigmented in adults; caudal saddle and bar merged dorsally in specimens in which they are still visible (Ref. 44050).

Description: head deep and cylindrical; body elongate and fusiform, not depressed; eyes lateral and relatively large; jaws equal; 16-18 abdominal vertebrae; 21-24 caudal vertebrae; 19 caudal-fin rays (arrangement usually ii-7-8-ii, but also iii-7-8-ii and ii-6-8-ii) (Ref. 44050, 57130).

Coloration: body and head bicolored; dorsum light brown (or grey or blue-grey), with venter much lighter, but still marked with a diffuse speckling of dark pigment; underside of head dusky; dorsum and flank well marked with mostly small spots, few more than 2-3 times an eye diameter, with a few small spots scattered on venter; paired fins dusky, rarely bearing spots; anal fin darkly pigmented throughout with a clear distal margin, often also bearing scattered small spots; caudal fin darkly pigmented with a well defined pale distal margin, and a pale basal crescent in young; caudal saddle and bar pattern prominent in juveniles and young, growing fainter with increasing size and largely gone by 140mm SL; when still visible, the caudal bar and saddle are broadly merged across the dorsal 2/3 of the flank, leaving a fairly small portion of the pale interspace visible ventrally; adipose fin darkly pigmented, with a pale distal rim; tiny juveniles are largely unpigmented with very faint spotting or caudal barring (Ref. 44050).

Ease of Identification

Meristic characteristics of Malapterurus stiassnyae

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
Gill clefts (sharks/rays only)
Gill rakers
on lower limb 15 - 23
on upper limb 2 - 3
total 18 - 26
total 38 - 42


Dorsal fin(s)

Attributes greatly reduced or absent
Fins number
Finlets No. Dorsal   0
Ventral  0
Spines total 0
Soft-rays total 0
Adipose fin present

Caudal fin

Attributes more or less truncate; more or less normal

Anal fin(s)

Fins number 1
Spines total 0
Soft-rays total 8 - 11

Paired fins

Pectoral Attributes  more or less normal
Spines     0
Soft-rays   8 - 11
Pelvics Attributes  more or less normal
Position    abdominal
Spines     0
Soft-rays   6
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