Morphology Data of Oreochromis mweruensis
Identification keys
Main Ref. Trewavas, E., 1983
Appearance refers to Male; Female
Bones in OsteoBase

Sex attributes

Specialized organs genital papilla with tassels (m)
Different appearance different morphology during breeding season only
Different colors different colors during breeding season only

Descriptive characteristics of juvenile and adult

Striking features none
Body shape lateral short and / or deep
Cross section compressed
Dorsal head profile clearly convex
Type of eyes more or less normal
Type of mouth/snout more or less normal
Position of mouth terminal
Type of scales cycloid scales

Diagnosis: scales on cheek in 2-3 rows; caudal scales variable, not on the inter-radial membranes except at the base; never stiffening the fin; genital papilla large and tuberculate or scalloped, tasseled in breeding males; generally lighter or darker olive-green; breeding male iridescent dark green to blue-black on head, body and vertical fins; red edge to dorsal and caudal fins (Ref. 2).

Description: body deep with a deep caudal peduncle; snout short; frontal profile rounded; sexual dimorphism well-developed; males possess better developed finnage and their pelvic fins are notable for having very long rays that can reach or overlap the origin of the anal fin (Ref. 52307).

Coloration: body color light to dark gray; body scales with a shiny center in most cases; generally speaking, the entire fish is very light in color; head greenish to bluish; entire head, cheeks and opercles with many black dots or worm-like lines; unpaired fins with red margins; dorsal and caudal fin (and rarely anal fin) with a number of pale dots; ripe and courting males can appear nearly black, but the silvery centers of their body scales remain visible (Ref. 52307).

Ease of Identification

Meristic characteristics of Oreochromis mweruensis

Lateral Lines 2 Interrupted: No
Scales on lateral line 29 - 33
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) absent
Gill rakers
on lower limb 20 - 26
on upper limb
total 30 - 32


Dorsal fin(s)

Attributes extending over most of the back length
Fins number 1
Finlets No. Dorsal   0
Ventral  0
Spines total 15 - 17
Soft-rays total 11 - 14
Adipose fin absent

Caudal fin

Attributes more or less truncate; more or less normal

Anal fin(s)

Fins number 1
Spines total 3 - 3
Soft-rays total 9 - 12

Paired fins

Pectoral Attributes  more or less normal
Pelvics Attributes  more or less normal
Position    thoracic  behind origin of D1
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Acosta, Belen
Modified by Musschoot, Tobias
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