Morphology Data of Tylochromis sudanensis
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 clearly evident in specimens of >10cm SL; in smaller males (ca 10cm SL) the anterior 4-5 outer row teeth in the lower jaw are fine and caniniform, while the lateral teeth are larger, blunter and more widely spaced; in larger specimens (>15cm SL) the anterior outer row teeth are also enlarged, stout and rather blunt (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: 13 or fewer (rarely 14) gill-rakers along lower limb of first arch; 37-43 lateral line scales; head length 28.0-34.1% of standard length; predorsal length 36.5-43.2% of standard length; more gradual rise in dorsal spine length from 1st to 6th-7th; pectoral fin relatively short, rarely reaching level of spinous anal fin (Ref. 52346).

Description: moderately deep bodied, greatest body depth at or a little behind dorsal fin origin; predorsal profile rises over snout at an angle of about 45° to the horizontal, decreases abruptly over eyes and rises again slightly less steeply to dorsal fin origin (Ref. 52346, 81260). Resultant concavity in orbital region frequently pronounced; lower jaw slightly oblique, sloping at an angle of about 10° to the horizontal when mouth is closed; lower pharyngeal jaw relatively robust, even in juveniles; lips moderately fleshy and well developed, but not markedly so; inferior vertebral apophysis borne only on third vertebral centrum, which is a large, rather broad wedgeshaped process which extends caudally and slightly underlaps fourth vertebral centrum (Ref. 52346). Outer and inner jaw teeth monocuspid; posterior pharyngeal jaw teeth molariform (Ref. 53405). Stout, crenate rakers along the lower limb of first arch (Ref. 52346, 53784). Stout epibranchial rakers along upper limb of first arch; raker at angle of first arch often forked (Ref. 52346). Micro-gillrakers present (Ref. 53405). 2 series of scales between upper lateral line and anterior part of lower (Ref. 2756, 31256). Scales cycloid (Ref. 53405). 37-43 lateral line scales (Ref. 7378, 52346, 53405). 5.5-6 scales between upper lateral line and dorsal fin origin; 12-14 scales between lower lateral line and anal fin (Ref. 2756). Upper branch of lateral line terminates well in advance of end of soft dorsal fin (Ref. 52346, 81260), usually below 6th-7th ray from free end; terminal canal bearing scales never descend scale rows; dorsal and ventral lateral line branches on caudal fin extend almost to fin periphery; median branch less well developed (sometimes entirely lacking) and usually does not extend much beyond halfway to fin periphery; dorsal fin spines increase gradually in length to 6th-7th and are then more or less equal in length; anal fin rounded (Ref. 52346). Pectorals relatively short, barely reaching level of spinous anal fin (Ref. 52346, 81260), even in largest specimens (Ref. 52346). First branched pelvic ray often produced and filamentous, often reaching to level of soft anal fin (Ref. 52346). Caudal fin emarginate and finely scaled (Ref. 52346, 53784). Caudal fin in juveniles only scaled to fin periphery at its dorsal and ventral margins (Ref. 52346).

Coloration: body yellow-brown; mouth, cheeks, opercles, breast and belly whitish-silvery; many bodyscales with iridescent center (Ref. 52307). In life: silvery with golden longitudinal lines between scale rows; more or less distinct dark cross bars on upper part of sides; pectoral fins, anal and caudal fin yellow; pelvic fins grey; dorsal fin membrane with dark lines forming a light-meshed network; upper margin of dorsal and caudal fins bright red (Ref. 7378, 52346, 53405). Preserved specimens: uniformly light brown, with 7-8 narrow cross bars on flanks extending beyond midline (Ref. 7378, 52346, 53405, 81260). Ethmoidal region dark; opercular blotch diffuse; nape band short; dorsal fin smoky grey with rows of pale maculae; larger males with traces of a few small pale maculae on proximal region of anal fin; caudal fin of male streaked with numerous thin, dark caudal stripes; in juveniles only alternate vertical stripes extend below midline, remainder extend only a little onto dorsum in typical juvenile barring (Ref. 52346).

Ease of Identification

Meristic characteristics of Tylochromis sudanensis

Lateral Lines 2 Interrupted: No
Scales on lateral line 37 - 43
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line 5.5 - 6
Scale rows below lateral line 12 - 14
Scales around caudal peduncle
Gill clefts (sharks/rays only)
Gill rakers
on lower limb 12 - 14
on upper limb 5 - 8
total 17 - 21
total 28 - 29


Dorsal fin(s)

Fins number 1
Finlets No. Dorsal   0
Ventral  0
Spines total 13 - 16
Soft-rays total 13 - 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  
Soft-rays   13 - 15
Pelvics Attributes  
Soft-rays   1 - 5
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
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