Morphology Data of Oreochromis karongae
Identification keys
Abnormalities
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
Remarks Breeding males black; females and juvenile brownish, often with yellow dorsal margin (Ref. 6150, 55079).

Descriptive characteristics of juvenile and adult

Striking features none
Body shape lateral fusiform / normal
Cross section compressed
Dorsal head profile more or less straight
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

Diagnosis: A heavily-built large tilapia species with a wide rounded head and short jaws; individuals vary a lot in dentition, with some having very wide bands of jaw teeth (Ref. 118638). Head length 30.8-36.0% of standard length; lower pharyngeal with large toothed area with straight or slightly convex sides; median length of pharyngeal bone 1.14-1.32 times its width and 38.2-42.2% of head length; blade 1.0-1.7 times median length of toothed area; length of lower jaw 28.4-34.5% of head length; teeth of jaws in 4-6 rows (Ref. 2). Females and juveniles with greyish-brown bodies and 4-5 vertical bars (Ref. 118638). Males are black with a white margin to the dorsal and tailfins; the genital tassel can be long and branched and pinkish to bright yellow (Ref. 2, 118638). It is one of the 'chambo' group Oreochromis from the Lake Malawi catchment; females and non-territorial males cannot be reliably distinguished from those of Oreochromis squamipinnis; females and non-territorial males from Lake Ikapu are a bright golden colour (Ref. 118638).

Description: Upper profile of snout before eye usually convex (Ref. 55427). Jaws small (Ref. 6150). Tooth band wide (Ref. 4967). Lower pharyngeal bone heavily developed; size of head and jaws, depth of body and number of tooth rows population dependent (Ref. 55079). Sides of triangular toothed area of lower pharyngeal bone not concave (Ref. 55427). Caudal fin scaly (Ref. 2, 55427) and emarginate (Ref. 2). In adults both upper and lower lobes of caudal fin rounded; caudal peduncle as long as or longer than deep; genital papilla prominent and bifid in breeding fishes (Ref. 2). Males develop a breeding dress (Ref. 5595) and a genital tassel (Ref. 5595, 44514), each branch bearing tubercles and filaments (Ref. 2).

Colouration: Non-breeding fish: silver-grey, darker on the dorsum, with black vertical bars of uneven length from the dorsum to mid-flanks (Ref. 2). Ripe females: very dark, almost black (Ref. 55079). At some times of the year (Ref. 55079) females, juveniles and non-breeding fish develop a yellowish-brown body with yellow margin to the dorsal fin (Ref. 6150, 55079). Courting male: black (Ref. 2781, 4967, 6150, 55079), often with iridescent patches on the head or body (Ref. 55079). Flank scales often with coppery metallic spot (Ref. 55079). Broad white margins to dorsal (Ref. 2, 55427) and caudal fin and sometimes also to the anal fin (Ref. 2). Black color lost in a few seconds when alarmed, turning a pale grey, often with iridescent greenish or coppery areas on the flanks or head (Ref. 40193).

Ease of Identification

Meristic characteristics of Oreochromis karongae

Lateral Lines 1 Interrupted: No
Scales on lateral line 33 - 36
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 17 - 22
on upper limb
total
Vertebrae
preanal
total 30 - 32

Fins

Dorsal fin(s)

Attributes extending over most of the back length
Fins number 1
Finlets No. Dorsal   
Ventral  
Spines total 15 - 17
Soft-rays total 10 - 12
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 8 - 10

Paired fins

Pectoral Attributes  more or less normal
Spines     
Soft-rays   
Pelvics Attributes  more or less normal
Position    thoracic  beneath origin of D1
Spines     
Soft-rays   
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
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