Morphology Summary - Oreochromis niloticus
Morfologiska data för Oreochromis niloticus
Bestämningsnycklar
Abnormalities
Main Ref. Trewavas, E., 1983
Utseende refererar till hane; hona
Bones in OsteoBase Skull, Spine

Könskaraktärer

specialiserade organ
annat utseende different morphology during breeding season only
andra färger different colors during breeding season only
Anmärkningar

Karaktäristiska egenskaper hos juveniler och adulter

Särskilt slående egenskaper none
Lateral kroppsform  (shape guide) fusiform / normal
Tvärsnitt compressed
Dorsal profil av huvudet more or less straight
Ögontyp more or less normal
Typ av mun/snyte more or less normal
Munnens placering terminal
Type of scales cycloid scales
Diagnos

Diagnosis: A large deep-bodied tilapia, with a relatively small head (Ref. 118638). Jaws of mature male not greatly enlarged, length of lower jaw 29-37% of head length; genital papilla of breeding male not tassellated (Ref. 2). Body depth 36-50% of SL (Ref. 28714). Most distinguishing characteristic is the presence, at all life stages, of regular vertical stripes throughout depth of caudal fin (Ref. 4967, 53405, 118638). In smaller fishes, these are relatively wide and form an arc, and start at the base of the caudal fin (Ref. 118638). Males are bluish pink, sometimes with a dark throat, belly, anal and pelvic fins; females are usually brownish, silvery/white beneath with around 10 thin vertical bars (Ref. 118638).

Description: Lower pharyngeal bone longer than broad, its anterior part longer than toothed part; outer jaw teeth bicuspid, inner jaw teeth tricuspid, posterior pharyngeal teeth bicuspid and stout; 3-4 rows of teeth in jaws (3-5, rarely 6, in specimens over 200 mm SL); micro-gillrakers present; scales cycloid (Ref. 53405).

Coloration: margin of dorsal fin grey or black; vertical bars in caudal fin 7-12 (Ref. 2). Regular black cross bars on caudal fin; ground colour greyish, relatively dark in adults; back olivaceous-green, sides paler, with 6-9 rather indistinct cross bars; belly whitish; upper lip pale green or white, lower lip white; dorsal and anal fins greyish, sometimes with very narrow red margin, soft part of fin with vertical lines (or with aligned light spots resembling striped pattern); pelvic fins grey, pectorals transparent; "tilapian" spot lacking in adults but very distinct in fingerlings which also have more distinct cross bars and very prominent black spot on upper part of caudal peduncle; throat, belly and unpaired fins black in mature males (Ref. 53405). Head and trunk in breeding male suffused with red (Ref. 28714).

Ease of Identification

Meristiska karaktäristika för Oreochromis niloticus

Sidolinjer 1 avbruten: No
Fjäll längs sidolinje 31 - 34
Porbärande fjäll längs sidolinje
Fjäll i lateralserie
Antal rader fjäll ovan sidolinje 4 - 5
Antal rader fjäll under sidolinje
Fjäll runt stjärtfensspole
Skäggtömmar 0
Gälspringor (endast hos hajar/rockor) absent
Gälräfständer
på undre del av gälbåge 18 - 28
på övre del av gälbåge
totalt
Ryggkotor
preanal
totalt 30 - 32

Fenor

Ryggfena/fenor

Egenskaper extending over most of the back length
Antal fenor 1
Antal småfenor Dorsal   0 - 0
Ventral  0 - 0
Totalt antal hårda fenstrålar 15 - 18
Totalt antal mjuka fenstrålar 11 - 13
Fettfena absent

Stjärtfena  (shape guide)

Egenskaper more or less truncate; more or less normal

Analfena/fenor

Antal fenor 1
Totalt antal hårda fenstrålar 3 - 3
Totalt antal mjuka fenstrålar 9 - 11

Pariga fenor

Bröstfena Egenskaper  more or less normal
Fenstrålar hårda     
Fenstrålar mjuka   
Bukfenor Egenskaper  more or less normal
Position    thoracic  beneath origin of D1
Fenstrålar hårda     1
Fenstrålar mjuka   
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