Morphology Data of Acanthurus nigricans
Identification keys
Abnormalities
Main Ref. Myers, R.F., 1991
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance
Different colors
Remarks

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
Type of scales
Diagnosis

A horizontally elongate white blotch directly below eye. No orange band in outer part of dorsal fin. Caudal peduncle black except for yellow edge of socket and sheath of peduncular spine. Base of pectoral fin black (ref 9808).Gill rakers on anterior row:17-19, on posterior row:18-20.

Description: Characterized further by blackish or dark grey body color; white patch below eye; white ring behind mouth; base of dorsal and anal fins with yellow zone that gradually widens towards rear part of fins; caudal spine yellow; caudal fin yellow with submarginal band; caudal spine length 2.5-3.0 in head length; greatest depth of body 1.7-1.9 in SL (Ref. 90102).

Ease of Identification likely to be confused with closely related species.

Meristic characteristics of Acanthurus nigricans

Lateral Lines 1 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
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
total
Vertebrae
preanal
total

Fins

Dorsal fin(s)

Attributes
Fins number 1
Finlets No. Dorsal   
Ventral  
Spines total 9 - 9
Soft-rays total 28 - 31
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 26 - 28

Paired fins

Pectoral Attributes  more or less normal
Spines     0
Soft-rays   16 - 16
Pelvics Attributes  more or less normal
Position    thoracic  beneath origin of D1
Spines     
Soft-rays   
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