Morphology Data of Malapterurus beninensis
Identification keys
Abnormalities
Main Ref. Norris, S.M., 2002
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance
Different colors
Remarks

Descriptive characteristics of juvenile and adult

Striking features
Body shape lateral fusiform / normal
Cross section circular
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth
Type of scales
Diagnosis

Diagnosis: body cylindrical; tooth patches narrow; vertically oriented pectoral fins, placed near body mid-depth; 6-7 branched caudal-fin rays; pectoral-fin rays usually 8, rarely 7 or 9; 34-38 vertebrae; eyes relatively small, interorbital space relatively broad; caudal saddle and bar pattern quite distinct in juveniles and young and usually apparent in adults (Ref. 44050), but often subdued (Ref. 81645). Dorsum and flank nearly always spotted, sometimes extensively (Ref. 44050, 81645). Commonly 10-15 gill rakers on first arch (total range 4-22)(Ref. 44050). Caudal saddle and anal-fin pigmentation not continuous (Ref. 44050, 81645). Venter often dusky, occasionally lightly spotted (Ref. 81645).

Description: body typically somewhat wider towards head; head deep and cylindrical; jaws even, or lower jaw only slightly prominent; 13-17 abdominal vertebrae; 19-23 caudal vertebrae; 18-19 caudal-fin rays (arrangement: ii-iii-6-7-ii-iii, abberantly 7 dorsal branched rays; where upper and lower lobes of caudal fin reported separately, separated by the dash between the numbers, unbranched elements represented by upper case ā€˜Iā€™; branched elements by numbers) (Ref. 44050, 57130, 81644).

Coloration: head and body bicolored, grey, with their dorsal and lateral surfaces usually spotted; spots small, generally no larger than 2-3 times an eye diameter, with spots rarely present on any fin; caudal saddle and bar pattern well developed, although often subdued in adults; wide caudal bar rounded or wedge-shaped, projecting anteriad into the pale interspace and also marking the base of the caudal fin; pale interspace usually lighter than flank or dorsum ground color; caudal saddle variable, dark or faint, narrow or relatively wide, usually with an irregular anterior border; it may cross the body mid-depth, but clearly stops short of anal-fin base; saddle and bar pattern decrease in definition with body size, with the saddle fading more dramatically; pectoral fin frequently dusky; pelvic fin usually clear; anterior half of adipose fin marked by the saddle, the posterior half usually matches pale interspace; anal fin carries a dusky stripe, with a pale distal margin, more distinct in juveniles and young; anal fin sometimes dusky overall matching flank ground color; caudal fin usually with dark bar distally, with clear distal margin and pale basal crescent; caudal fin sometimes dusky overall, matching flank ground color, with little indication of a dark bar, pale margin or basal crescent (Ref. 44050). Displays marked variation in pigmentation across its range (Ref. 81645).

Ease of Identification

Meristic characteristics of Malapterurus beninensis

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 8
Gill clefts (sharks/rays only)
Gill rakers
on lower limb 4 - 19
on upper limb 0 - 3
total 4 - 22
Vertebrae
preanal
total 33 - 38

Fins

Dorsal fin(s)

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

Caudal fin

Attributes

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   7 - 9
Pelvics Attributes  more or less normal
Position    abdominal
Spines     0
Soft-rays   6
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
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cfm script by eagbayani, 17.10.00, php script by rolavides, 13/03/08 ,  last modified by sortiz, 06.27.17