Morphology Data of Naso unicornis
Identification keys
Main Ref. Randall, J.E., 2005
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance
Different colors

Descriptive characteristics of juvenile and adult

Striking features other (see diagnosis)
Body shape lateral short and / or deep
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 ctenoid scales

This species is characterized by the following: body depth vary from about 2.0 in SL (in subadults) to 2.4-2.6 (adults) in SL; with a tapering, bony, horn on forehead of adults projecting anteriorly at level of eye but not extending in front of mouth (horn first as a bump on forehead at a length of about 12 cm); dorsal profile from snout to horn straight, angle of about 45°; 2 peduncular plates with well-developed forward-curving knife-like spines; emarginate caudal fin when young, truncate with filamentous lobes in adult; males apparently with longer horn, larger peduncular keels and longer caudal filaments than females of the same size; body yellowish to olivaceous gray dorsally, paler ventrally, with blue peduncular plates and keel spines; lips whitish or blue; blue area is sometimes present around pectoral fin; dorsal and anal fins yellowish with narrow blue margins; caudal fin orangish basally, shading to gray, with a broad, pale greenish posterior border and caudal filaments are edged in blue; one transient color phase is a blotchy pale greenish zone below the spinous portion of dorsal fin that narrows and ends beneath the pectoral fin (Ref. 27362).

Ease of Identification

Meristic characteristics of Naso unicornis

Lateral Lines 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 0
Gill clefts (sharks/rays only)
Gill rakers
on lower limb 9 - 10
on upper limb 4 - 4
total 13 - 14


Dorsal fin(s)

Attributes no striking attributes
Fins number 1
Finlets No. Dorsal   0 - 0
Ventral  0 - 0
Spines total 6 - 6
Soft-rays total 27 - 30
Adipose fin absent

Caudal fin

Attributes more or less truncate; with dorsal and ventral filament

Anal fin(s)

Fins number 1
Spines total 2 - 2
Soft-rays total 27 - 30

Paired fins

Pectoral Attributes  more or less normal
Spines     0
Soft-rays   17 - 18
Pelvics Attributes  more or less normal
Position    abdominal  behind origin of D1
Spines     1
Soft-rays   3 - 3
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
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