o VI-IX,25-27; A III ,23-24; P 16-17. Body depth 1.8-2.1, snout 6.8-7.0
in SL; mouth width about 3.8 in head; 24 upper and 28 lower jaw teeth at
153 mm SL; C concavity 6.7-9.5 in SL. Body dark yellowish brown with
numerous lengthwise blue lines; a broad brownish yellow area around
caudal spine; head and chest blue with numerous, close-set, round, dark
yellowish brown spots (about )j pupil diameter); 0 and A bluish grey
basally, greenish brown distally, with numerous dark brown bands; C
dark grey (white in life) .
Largest specimen, 26 cm. Described from Celebes
(Sulawesi); otherwise recorded only from the Society Ids.,
New Caledonia and 1 specimen, 95 mm SL, from the
Mozambique Channel at 25°S from 50 fathoms. This specimen differs from the Pacific ones in having D IX,25 instead
ofthe usual VII,27. Although this appears to be a majordifference, the number of dorsal elements are the same, and
the fish has the characters of A. nubilus in other respects. Its
identification is however provisional. The Bishop Museum
has specimens heretofore unreported from the Solomon
Ids., Cook Ids. and Austral Ids. This species has been
observed only at depths greater than about 25 m. It is usually seen well off the bottom and appears to feed on zooplankton.
243.8 Acanthurus nubi/us: 24.5 em holotype (after Fowler & Bean, 1929).
243.9 Acanthurus tennenti
Gunther, 1861
Lieutenant surgeonfish
Luitenant-doktervis
Acanthurus tennenti Gunther , 1861: 337 (Ceylon) ; Randall, 1956: 205' ;
Smith, 1980: 179. Acanthurus bicommatus Smith, 1955: 694, PI. 18, Figs.
C & D (Shimoni , Kenya) .
o IX,23-24; A 1II,22-23; P 16. Body depth 1.9-2.2 (body more elongate
with growth) ; 15 upper and 16 lower jaw teeth at \05 mm SL, and 20 upper
and 22 lower at 214 mm SL; C concavity 5 in SL at 214 mm and \0 at 105
mm SL. Brown with a horseshoe-shaped black mark (open end forward)
on shoulder region in fish up to 12 cm SL; above this size the mark breaks
into 2 horizontal, slightly curved bands which are pointed posteriorly;
caudal spine enclosed in a black area surrounded by bluish white (black
area progressively larger and white margin smaller with growth) ; C with a
white posterior border which narrows as it passes onto pointed lobes of fin
(larger individuals show some white on outer edges of lobes as well) .
Attains 31 cm. Western Indian Ocean from Natal to Sri
243: ACANTHURIDAE (SURGEONFISHES, UNICORNFISHES)
Lanka. Closely related to the Pacific A. olivaceus Bloch &
Schneider, 1801.
243.9 Acanthurus tennenti: top: 24.5 em holotype (Kenya); bottom: 11 em
paratype of A. bicommatus (Seychelles).
243.10 Acanthurus thompsoni
(Fowler, 1923)
PLATE 129
Chocolate surgeon
Sjokolade-doktervis
Hepatus thompsoni Fowler, 1923: 386 (Honolulu). Acanthurus philippinus: Smith, 1955: 692. Acanthums thompsoni: Randall , 1956: 182';
Smith, 1980: 179.
o IX,23-26; A 1II,23-26; P 17. Body depth about 2.3, snout 7.9-8.2 in
SL; mouth width about 4 in head ; adults with 20-21 upper and 24 lower jaw
teeth; C lunate, concavity about 5 in SL. Uniform brown to dark brown ; a
darker brown spot below and adjacent to P axil (difficult to see on dark
specimens); individuals from the Pacific have white C.
Attains 27 cm. Indo-Pacific, south to Sodwana Bay.
Feeds on zooplankton.
243.10 Acanthurus thompsoni: 20 em (N . Mozambique).
815
in SL; mouth width about 3.8 in head; 24 upper and 28 lower jaw teeth at
153 mm SL; C concavity 6.7-9.5 in SL. Body dark yellowish brown with
numerous lengthwise blue lines; a broad brownish yellow area around
caudal spine; head and chest blue with numerous, close-set, round, dark
yellowish brown spots (about )j pupil diameter); 0 and A bluish grey
basally, greenish brown distally, with numerous dark brown bands; C
dark grey (white in life) .
Largest specimen, 26 cm. Described from Celebes
(Sulawesi); otherwise recorded only from the Society Ids.,
New Caledonia and 1 specimen, 95 mm SL, from the
Mozambique Channel at 25°S from 50 fathoms. This specimen differs from the Pacific ones in having D IX,25 instead
ofthe usual VII,27. Although this appears to be a majordifference, the number of dorsal elements are the same, and
the fish has the characters of A. nubilus in other respects. Its
identification is however provisional. The Bishop Museum
has specimens heretofore unreported from the Solomon
Ids., Cook Ids. and Austral Ids. This species has been
observed only at depths greater than about 25 m. It is usually seen well off the bottom and appears to feed on zooplankton.
243.8 Acanthurus nubi/us: 24.5 em holotype (after Fowler & Bean, 1929).
243.9 Acanthurus tennenti
Gunther, 1861
Lieutenant surgeonfish
Luitenant-doktervis
Acanthurus tennenti Gunther , 1861: 337 (Ceylon) ; Randall, 1956: 205' ;
Smith, 1980: 179. Acanthurus bicommatus Smith, 1955: 694, PI. 18, Figs.
C & D (Shimoni , Kenya) .
o IX,23-24; A 1II,22-23; P 16. Body depth 1.9-2.2 (body more elongate
with growth) ; 15 upper and 16 lower jaw teeth at \05 mm SL, and 20 upper
and 22 lower at 214 mm SL; C concavity 5 in SL at 214 mm and \0 at 105
mm SL. Brown with a horseshoe-shaped black mark (open end forward)
on shoulder region in fish up to 12 cm SL; above this size the mark breaks
into 2 horizontal, slightly curved bands which are pointed posteriorly;
caudal spine enclosed in a black area surrounded by bluish white (black
area progressively larger and white margin smaller with growth) ; C with a
white posterior border which narrows as it passes onto pointed lobes of fin
(larger individuals show some white on outer edges of lobes as well) .
Attains 31 cm. Western Indian Ocean from Natal to Sri
243: ACANTHURIDAE (SURGEONFISHES, UNICORNFISHES)
Lanka. Closely related to the Pacific A. olivaceus Bloch &
Schneider, 1801.
243.9 Acanthurus tennenti: top: 24.5 em holotype (Kenya); bottom: 11 em
paratype of A. bicommatus (Seychelles).
243.10 Acanthurus thompsoni
(Fowler, 1923)
PLATE 129
Chocolate surgeon
Sjokolade-doktervis
Hepatus thompsoni Fowler, 1923: 386 (Honolulu). Acanthurus philippinus: Smith, 1955: 692. Acanthums thompsoni: Randall , 1956: 182';
Smith, 1980: 179.
o IX,23-26; A 1II,23-26; P 17. Body depth about 2.3, snout 7.9-8.2 in
SL; mouth width about 4 in head ; adults with 20-21 upper and 24 lower jaw
teeth; C lunate, concavity about 5 in SL. Uniform brown to dark brown ; a
darker brown spot below and adjacent to P axil (difficult to see on dark
specimens); individuals from the Pacific have white C.
Attains 27 cm. Indo-Pacific, south to Sodwana Bay.
Feeds on zooplankton.
243.10 Acanthurus thompsoni: 20 em (N . Mozambique).
815