Morphology Data of Tylochromis variabilis
Identification keys
Main Ref. Stiassny, M.L.J., 1989
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance always different morphology between mature adults
Different colors
Remarks Sexual dimorphism of the buccal dentition is marked and clearly evident in specimens of >11cm SL; in mature males the outer row teeth in both jaws are larger and somewhat coarser than those of females of equivalent size (Ref. 52346).

Descriptive characteristics of juvenile and adult

Striking features
Body shape lateral short and / or deep
Cross section
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth
Type of scales

Diagnosis: 33-35 lateral line scales; 15-16 gill-rakers along lower limb of first arch; entire premaxillary oral valve present; dorsal fin length of 55.4-65.5% SL (Ref. 52346).

Description: relatively deep bodied and robust; predorsal profile more or less straight, rising at an angle of about 50-60° to the horizontal; fleshy bulge in interorbital region frequently present; snout length variable: some specimens with a straight-snouted appearance, others with a shorter snout, a somewhat inclined lower jaw and a definitely pugnacious aspect; dorsum variously recurved from nape to caudal peduncle; deepest body depth may be at dorsal fin origin, or as far back as below 5th-6th spine; mouth a little inclined from the horizontal when closed, but inclination rarely strongly marked, except in certain deep bodied, short-snouted individuals from the Luvua River with a quite steeply inclined lower jaw, often at an angle of about 15-20° to the horizontal; lips thick and reasonably fleshy; lower pharyngeal jaw mostly robust and well ossified; inferior vertebral apophysis well developed and robust, and of standard Tylochromis type; broad, crenate gill-rakers closely overlapping for length of lower limb of first arch; 2-3 short hypobranchial rakers usually present; short and thick epibranchial rakers fringe upper limb of first arch; 33-35 lateral line scales (Ref. 52346). 7-8 scales below lower lateral line; 3 scale rows on cheek below eye (Ref. 42005). Upper branch of lateral line usually terminates a little in advance of end of dorsal fin, but may extend full length of fin; terminal canal bearing scales often descend a scale row, canal then continuing for another 2(-3) scales; dorsal and ventral branches of lateral line on caudal fin well developed and extending almost to fin periphery; median branch usually well developed, but rarely extending much beyond 2/3 of caudal fin length; dorsal fin spines increase gradually in length to (5th) 6th-7th and are then more or less equal in length; anal fin rounded; pectoral fins rather short, rarely reaching beyond level of vent; first branched pelvic ray somewhat produced but rarely markedly filamentous; caudal fin slightly emarginate and usually heavily scaled almost to fin periphery (Ref. 52346). Coloration: pearl grey and greenish above in more or less longitudinal stripes, whitish below, silvery troughout; scales of caudal peduncle and flank in larger individuals ringed in dark brown pigment, resulting in a series of longitudinal striations passing along scale rows; longitudinal striping most pronounced on caudal peduncle and dorsum; vertical stripes less prominent in adults and completely absent in specimens of 15cm SL (Ref. 52346). Dorsal fin transparent grey with bright blue reflections on spines and brownish-red longitudinal markings; caudal fin greyish edged with red on lower half (Ref. 52307, 52346). Pectoral fins transparent grey; pelvic and anal fins pale blue-grey (Ref. 52307, 52346), former with red markings anteriorly (Ref. 52346). Anal fin of mature male fish smoky brown with a few rows of pale non-ocellate maculae that are typically lacking in females; mature males exhibit caudal fin striping and spotting; top of head in front of eyes dark grey; gill covers yellowish and an area behind head dusky yellowish grey; some red markings between pelvic and pectoral fins (Ref. 52346). Preserved juveniles: strong nape stripe separated from dark opercular blotch; 7-8 thick vertical strips which extend down onto flank well below midline, often almost to ventrum; juvenile barring usually pronounced in specimens of less than 6-7cm SL; dorsal fin dark grey brown and spotted with numerous rows of non-ocellate pale maculae (Ref. 52346).

Ease of Identification

Meristic characteristics of Tylochromis variabilis

Lateral Lines 2 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 16
Barbels 0
Gill clefts (sharks/rays only)
Gill rakers
on lower limb 15 - 16
on upper limb 8 - 10
total 23 - 25
total 28 - 29


Dorsal fin(s)

Fins number 1
Finlets No. Dorsal   0
Ventral  0
Spines total 14 - 16
Soft-rays total 11 - 16
Adipose fin absent

Caudal fin


Anal fin(s)

Fins number 1
Spines total 3 - 3
Soft-rays total 7 - 8

Paired fins

Pectoral Attributes  
Spines     1
Soft-rays   14
Pelvics Attributes  
Spines     1
Soft-rays   5
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
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