Morphology Data of Tylochromis robertsi
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 only evident in large individuals (>16cm SL), and even in the largest specimens the extent of dental dimorphism is muted; outer row dentition in both upper and lower jaw is slightly coarser in males than in females of equal size (Ref. 52346).

Descriptive characteristics of juvenile and adult

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

Diagnosis: upper lateral line extending full length of dorsal fin base and descending a row before proceeding length of three or more scales; 14-15 gill-rakers, widely spaced along lower limb of first arch; 36-40 lateral line scales; head length 29.0-35.7% of standard length; usually 29 vertebrae; inferior vertebral apophysis short and oriented caudad rather than of standard Tylochromis type (Ref. 52346).

Description: relatively shallow bodied and elongate; predorsal profile rises steeply over snout, frequently lending a blunt-nosed appearance; profile interrupted by a fleshy thickening of interorbital region, after which profile rises less steeply to origin of dorsal fin; deepest body depth along back lies at dorsal fin origin; lower jaw often slightly inclined from horizontal when mouth is closed; lower pharyngeal jaw robust; lips thick and fleshy; buccal mucosa separating left and right tooth bands in upper jaw frequently hypotrophied and raised into a distinct fleshy median ridge; inferior vertebral apophysis borne on third vertebra with only a very small buttressing component on fourth; apophysis shallow and strongly caudally directed; well-spaced, short and broad gill rakers along lower limb of first arch; hypobranchial with 2-3 short and broad rakers; epibranchial rakers stout; upper lateral line extending full length of dorsal fin base and descending a row before proceeding the length of three or more scales; 36-40 lateral line scales; dorsal fin spines increase in length to fourth and are then more or less equal in length; anal fin rounded; pectoral fins rather short, not reaching level of spinous anal fin; first branched pelvic ray frequently produced and filamentous, sometimes reaching beyond origin of soft anal fin; caudal fin emarginate and finely scaled to fin periphery (Ref. 52346).

Coloration: body green-grey, lower parts more silvery; upper lip, ethmoidal and interorbital region dark brown (Ref. 52307, 52346). Dorsum and flank silvery grey, tinged with bronze; belly pale yellowish silver; narrow golden line around pupil may be present; short black/brown nape band not extending down onto operculum and followed by traces of 5 short, dark bluish, vertical stripes not reaching below midline (Ref. 52346). Scales on dorsum and upper flanks outlined by a dark brown ring (Ref. 52307, 52346), giving a lattice like pattern to body (Ref. 52346). Scale pigmentation in ventral regions restricted to a small yellow/brown patch in ventral field of flank and belly scales, such that 2-3 rows of discrete pale spots adorn flanks; chest, branchiostegal membranes and lower lip creamy white; cheek and opercular region light silvery brown; opercular blotch faint and diffuse (Ref. 52346). A streak of red at corner of mouth; all fins dark brownish red, with numerous rows of light maculae only on dorsal fin (Ref. 52307, 52346). Preserved specimens: juveniles with 5-6 broad vertical stripes behind nape band, which are dorsally rather caudad oriented and rostrad directed at midline, giving a zigzagged pattern; interdigitating juvenile barring commonly present between stripes; vertical striping in adults far less evident; mature males with typical caudal fin stripes, sometimes with series of spots in stead of stripes (Ref. 52346).

Ease of Identification

Meristic characteristics of Tylochromis robertsi

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
Gill clefts (sharks/rays only)
Gill rakers
on lower limb 14 - 15
on upper limb 7 - 8
total 21 - 23
total 28 - 29


Dorsal fin(s)

Fins number 1
Finlets No. Dorsal   0
Ventral  0
Spines total 14 - 16
Soft-rays total 12 - 15
Adipose fin absent

Caudal fin


Anal fin(s)

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

Paired fins

Pectoral Attributes  
Pelvics Attributes  
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Comments & Corrections
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