Morphology Data of Tylochromis polylepis
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 evident in specimens of about 14-15cm SL; however, the dimorphism is muted and all individuals have a relatively fine buccal dentition; in mature males the teeth only differ in being slightly larger and in the tendency to have fewer inner rows in both jaws (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 sub-terminal/inferior
Type of scales

Diagnosis: high lateral line count (54-59 scales)(Ref. 52346). Scales small (Ref. 53244).

Description: body deep and narrow, laterally compressed, tappering off strongly toward caudal peduncle (Ref. 6770). Relatively slender, although adults sometimes with very massive heads (Ref. 52307, 52346). Adult predorsal profile rises smoothly in a broad sweep to origin of dorsal fin although line of profile is often somewhat interrupted by a thickening in interorbital region; deepest body depth lies at or a little in front of dorsal fin origin; lower jaw usually inclined at an angle of about 10° to horizontal when mouth is closed; lower pharyngeal jaw extremely robust (Ref. 52346). Pharyngeal apophysis of Tylochromis type (Ref. 53524). Large crushing pharyngeal teeth (Ref. 10616). Snout rounded (Ref. 52307). 4-5 series of scales on cheek (Ref. 2989). Larger scales on operculum (Ref. 1879, 45627). Hypobranchial with 2 simple elongate rakers, following 4-5 ceratobranchial rakers usually widely spaced and non-overlapping, and remaining lower limb rakers more closely spaced and overlapping; epibranchial rakers rather stout, elongate and closely packed; vertebral apophysis well-developed and robust, borne on third vertebral centrum and usually lacking a major contribution from fourth centrum, although in smaller individuals fourth centrum may contribute a small buttressing component; 54-59 lateral line scales (Ref. 52346). 25-33 scales in upper lateral line, 41-48 scales in lower lateral line; 6-8 scales between dorsal fin and upper lateral line; 16-19 scales between lower lateral line and anal fin (Ref. 45485). Upper branch of lateral line terminates far in advance of end of dorsal fin, often as far anterior as level of last dorsal spine; terminal canal bearing scales do not descend scale rows; 3 rows of non-pored scales between upper and lower lateral line; dorsal and ventral branches of lateral line on caudal fin extend almost to fin periphery while median branch is less developed and often reaches only as far as about halfway along fin; dorsal fin spines increase gradually in length to fifth and are then more or less equal in length to last 4-5 which are often slightly shorter than preceding ones; anal fin rounded (Ref. 52346). Anal fin spines very strong (Ref. 2989). Pectoral fins long and even in juveniles extending to level of middle of soft anal fin; first branched pelvic ray filamentous and often produced beyond soft anal fin; caudal peduncle relatively long and thin (Ref. 52346). Caudal fin subtruncate (slightly forked) (Ref. 52307), strongly emarginate, and rather finely scaled even in large individuals; caudal scaling in juveniles restricted to dorsal and ventral fields of fin (Ref. 52346).

Coloration: greyish or brownish above, white below; with or without 5-7 inconspicious vertical bars; pale yellow or green longitudinal striations between scale rows; mature males have a caudal fin striated in typical manner and a soft anal fin with 3-4 large non-occelate maculae; females and juveniles apparently without anal maculation, but with pale grey-brown fin membranes; nape stripe dark and prominent, but usually not in contact with faint and diffuse opercular blotch; a red vertical stripe on gill cover may be present, possibly restricted to mature males (Ref. 52346). Angle of jaws, origin of paired fins and tips of anterior dorsal fin spines reddish; a number of dark brown dots on dorsal fin (Ref. 52307, 52346). Juveniles less than 20cm do not display any of the colors of the adults (Ref. 6770). Juveniles less than ca. 12cm SL exhibit typical juvenile barring, with distinct dark vertical stripes interdigitated by pale and shorter stripes (Ref. 52346).

Ease of Identification

Meristic characteristics of Tylochromis polylepis

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
Barbels 0
Gill clefts (sharks/rays only)
Gill rakers
on lower limb 12 - 15
on upper limb 7 - 8
total 19 - 23
total 30


Dorsal fin(s)

Fins number 1
Finlets No. Dorsal   
Spines total 14 - 16
Soft-rays total 13 - 15
Adipose fin absent

Caudal fin

Attributes more or less normal

Anal fin(s)

Fins number 1
Spines total 3 - 3
Soft-rays total 7 - 9

Paired fins

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