14a C with numerous small black spots; sheath of caudal
spine white ; yellow band crossing or nearly crossing
interorbital space; body with numerous, slightly
wavy, pale bluish lengthwise lines; D and A of
adults mainly yellow without dark bands (or with
only a few narrow faint ones in outer part of fins) ... A. dussumieri
14b C without black spots; sheath of caudal spine brown;
no yellow band crossing interorbital space (a yellowish
area may extend anterior to eye but not as a distinct
band); body without pale bluish lengthwise lines; D
and A with alternating blue and brownish yellow
lengthwise bands .............. .................... .......................... 15
15a P dark brown basally , outer ~ yellowish in specimens
> 12 cm SL; D with 4 blue bands alternating
with brownish yellow; caudal spine length 4.5-5.5
in head ; GR 16-22 ........................................ A. xanthopterus
15b P uniform brown; D with 8 blue bands alternating
with brownish yellow; caudal spine 3.0-4.4 in head ;
GR20-25 ............................................................ A. blochii
243.1 Acanthurus blochii
Valenciennes, 1835
PLATE 129
Tailring surgeon
Stertring-doktervis
Acanthurus Blochii Valenciennes, in Cuv. & Val., 1835: 209 (Mauritius). Acanthurus mata (non Cuvier): Randall , 1956: 218*.
D IX ,25-27 ; A III ,23-25; P 17; GR 20-25. Body depth 1.9- 2.1 in SL; eye
diameter 4.2-5.0, caudal spine 3.0-4.4 in head ; 16 teeth in both jaws at
84 mm SL, and 20 teeth in both jaws at 247 mm SL; C emarginate in
young, lunate in adults: C concavity 6.2 in SL at 292 mm and 10 at 151 mm
SL. Body dark olive to dark bluish brown (underwater usually appears
almost black), with a colour phase of tiny pale spots following scale rows
(this phase can be abruptly assumed and just as quickly "turned off");
head below eye with horizontal, slightly wavy, alternating lines of deep
blue and dull yellow; yellowish spot nearly as large as eye behind and
adjacent to lower part of eye (usually lost in preservative); a black area
around caudal spine about twice as high as greatest spine width; D dull
yellow with 8 or 9 longitudinal blue lines except basally in soft portion
where fin becomes yellowish brown and blue bands follow rays; blue line
at base offin; A similar but with 5 or 6 blue bands; C deep blue, often with
a whitish to white bar across base.
Attains at least 42 cm. Indo-Pacific, south to Durban.
Closely tied to coral reefs for shelter, but often feeds on
algal film on sand.
243.2 Acanthurus dussumieri
Valenciennes, 1835
PLATE 129
Pencilled surgeon
Potlood-doktervis
Acanthurus dussumieri Valenciennes, in Cuv. & Val., 1835: 201
(Mauritius) . Acanthurus bariene (non Lesson) : Smith , SFSA No. 613*.
Acanthurus dussumieri: Randall, 1956: 213* .
D IX,25-27; A III,24-26; P 16-17; GR 22-26. Body depth 1.9-2.1 in SL
(decreasing with size); eye. diameter 3.4-4.7 in head; caudal spine
3-5 in head (relatively longer in larger fish); 16 upper and 18 lower jaw
teeth at 94 mm SL, and 20 upper and 22 lower teeth at 325 mm SL. C
lunate in adult. Brown with numerous longitudinal , slightly wavy blue
243: ACANTHURIDAE (SURGEONFISHES, UNICORN FISHES)
lines on body; a yellow band extending anteriorly from eye, often crossing
interorbital space, and a yellow area behind eye; socket of caudal spine
edged in black, the spine sheath whitish; D and A yellow, sometimes
becoming blue posteriorly , with a blue margin and blue band at base (2 or
3 longitudinal blue lines may be present in outer posterior part of these
fins, but these are absent in large adults); C blue with numerous small
black spots.
Attains 54 cm. Algoa Bay to western Pacific and
Hawaiian Ids.; common on Natal coast.
243.2 Acanthurus dussumieri: 44 cm (Seychelles).
243.3 Acanthurus leucosternon
Bennett, 1832
PLATES 127 & 130
Powder-blue surgeonfish
Poeierblou-doktervis
Acanthurus leucosternon Bennett, 1832: 183 (Ceylon); Smith, 1953:
518, No. 609a; Randall , 1956: 198* ; van der Elst, 1981: 97* .
D IX,28-30; A III ,23-26; P 15-16. Body depth 1.7-1.9 in SL; 10 upper
and 11 lower jaw teeth at 89 mm SL, and 11 upper and 12 lower teeth at
173 mm SL; C concavity 10-16 in SL. Body mainly blue with white chest.
Attains 23 cm. Sodwana Bay to Indonesia. A showy
inshore species sometimes seen in large aggregations.
243.4 Acanthurus lineatus
(Linnaeus, 1758)
PLATE 129
Bluebanded surgeon
Blouband-doktervis
Chaetodon lineatus Linnaeus, 1758: 274 (Indies). Acanthurus lineatus:
Smith, SFSA No. 610*; Randall, 1956: 193*; Smith, 1962: 509.
D IX,27-29; A III ,25-28; P 16. Body depth of adults about 2.2 in SL;
caudal spine very long, 1.9-2.0 in head ; C lunate, concavity 3.3-4.5 in SL.
Body with alternating black-edged blue and yellow stripes.
Attains 38 cm. Indo-Pacific; south to Durban. Replaced
in the Red Sea by the relatedA. sohal (Forsskal, 1775). The
strikingly coloured A. lineatus lives at the outer edge of
reefs exposed to wave action; it is generally seen at depths
of only 1 - 3 m. Territorial and very aggressive. The caudal
spine is venomous.
813
spine white ; yellow band crossing or nearly crossing
interorbital space; body with numerous, slightly
wavy, pale bluish lengthwise lines; D and A of
adults mainly yellow without dark bands (or with
only a few narrow faint ones in outer part of fins) ... A. dussumieri
14b C without black spots; sheath of caudal spine brown;
no yellow band crossing interorbital space (a yellowish
area may extend anterior to eye but not as a distinct
band); body without pale bluish lengthwise lines; D
and A with alternating blue and brownish yellow
lengthwise bands .............. .................... .......................... 15
15a P dark brown basally , outer ~ yellowish in specimens
> 12 cm SL; D with 4 blue bands alternating
with brownish yellow; caudal spine length 4.5-5.5
in head ; GR 16-22 ........................................ A. xanthopterus
15b P uniform brown; D with 8 blue bands alternating
with brownish yellow; caudal spine 3.0-4.4 in head ;
GR20-25 ............................................................ A. blochii
243.1 Acanthurus blochii
Valenciennes, 1835
PLATE 129
Tailring surgeon
Stertring-doktervis
Acanthurus Blochii Valenciennes, in Cuv. & Val., 1835: 209 (Mauritius). Acanthurus mata (non Cuvier): Randall , 1956: 218*.
D IX ,25-27 ; A III ,23-25; P 17; GR 20-25. Body depth 1.9- 2.1 in SL; eye
diameter 4.2-5.0, caudal spine 3.0-4.4 in head ; 16 teeth in both jaws at
84 mm SL, and 20 teeth in both jaws at 247 mm SL; C emarginate in
young, lunate in adults: C concavity 6.2 in SL at 292 mm and 10 at 151 mm
SL. Body dark olive to dark bluish brown (underwater usually appears
almost black), with a colour phase of tiny pale spots following scale rows
(this phase can be abruptly assumed and just as quickly "turned off");
head below eye with horizontal, slightly wavy, alternating lines of deep
blue and dull yellow; yellowish spot nearly as large as eye behind and
adjacent to lower part of eye (usually lost in preservative); a black area
around caudal spine about twice as high as greatest spine width; D dull
yellow with 8 or 9 longitudinal blue lines except basally in soft portion
where fin becomes yellowish brown and blue bands follow rays; blue line
at base offin; A similar but with 5 or 6 blue bands; C deep blue, often with
a whitish to white bar across base.
Attains at least 42 cm. Indo-Pacific, south to Durban.
Closely tied to coral reefs for shelter, but often feeds on
algal film on sand.
243.2 Acanthurus dussumieri
Valenciennes, 1835
PLATE 129
Pencilled surgeon
Potlood-doktervis
Acanthurus dussumieri Valenciennes, in Cuv. & Val., 1835: 201
(Mauritius) . Acanthurus bariene (non Lesson) : Smith , SFSA No. 613*.
Acanthurus dussumieri: Randall, 1956: 213* .
D IX,25-27; A III,24-26; P 16-17; GR 22-26. Body depth 1.9-2.1 in SL
(decreasing with size); eye. diameter 3.4-4.7 in head; caudal spine
3-5 in head (relatively longer in larger fish); 16 upper and 18 lower jaw
teeth at 94 mm SL, and 20 upper and 22 lower teeth at 325 mm SL. C
lunate in adult. Brown with numerous longitudinal , slightly wavy blue
243: ACANTHURIDAE (SURGEONFISHES, UNICORN FISHES)
lines on body; a yellow band extending anteriorly from eye, often crossing
interorbital space, and a yellow area behind eye; socket of caudal spine
edged in black, the spine sheath whitish; D and A yellow, sometimes
becoming blue posteriorly , with a blue margin and blue band at base (2 or
3 longitudinal blue lines may be present in outer posterior part of these
fins, but these are absent in large adults); C blue with numerous small
black spots.
Attains 54 cm. Algoa Bay to western Pacific and
Hawaiian Ids.; common on Natal coast.
243.2 Acanthurus dussumieri: 44 cm (Seychelles).
243.3 Acanthurus leucosternon
Bennett, 1832
PLATES 127 & 130
Powder-blue surgeonfish
Poeierblou-doktervis
Acanthurus leucosternon Bennett, 1832: 183 (Ceylon); Smith, 1953:
518, No. 609a; Randall , 1956: 198* ; van der Elst, 1981: 97* .
D IX,28-30; A III ,23-26; P 15-16. Body depth 1.7-1.9 in SL; 10 upper
and 11 lower jaw teeth at 89 mm SL, and 11 upper and 12 lower teeth at
173 mm SL; C concavity 10-16 in SL. Body mainly blue with white chest.
Attains 23 cm. Sodwana Bay to Indonesia. A showy
inshore species sometimes seen in large aggregations.
243.4 Acanthurus lineatus
(Linnaeus, 1758)
PLATE 129
Bluebanded surgeon
Blouband-doktervis
Chaetodon lineatus Linnaeus, 1758: 274 (Indies). Acanthurus lineatus:
Smith, SFSA No. 610*; Randall, 1956: 193*; Smith, 1962: 509.
D IX,27-29; A III ,25-28; P 16. Body depth of adults about 2.2 in SL;
caudal spine very long, 1.9-2.0 in head ; C lunate, concavity 3.3-4.5 in SL.
Body with alternating black-edged blue and yellow stripes.
Attains 38 cm. Indo-Pacific; south to Durban. Replaced
in the Red Sea by the relatedA. sohal (Forsskal, 1775). The
strikingly coloured A. lineatus lives at the outer edge of
reefs exposed to wave action; it is generally seen at depths
of only 1 - 3 m. Territorial and very aggressive. The caudal
spine is venomous.
813