27a AOa! abruptly elevated; 2 Pol in subvertical
line with last AOa; 4 (or more) Prc ... ... .......... ... Gymnoscopelus
27b AOa! not elevated; 2 or 3 Pol in a horizontal
line; 3 Prc .......... ... ...... ...... ... ............. ...... ....... . Notoscopelus
Genus Benthosema Goode & Bean, 1896
Maxilla expanded posteriorly, extending past orbit; A
base longer than Dbase. Dn and Vn small and poorly
defined; 5 PO; 4 VO; SAO series moderately to strongly
angulate; 1 Pol; AO series divided into AOa and AOp. Five
species; 3 in our area.
KEY TO SPECIES
la So present; SA03 about on vertical through
A origin ; PLO nearer upper base of P than
LL; total GR 13·15 ...... ............ ... ......... .... ..... .... . B. suborbitale
Ib So absent; SA03 well behind vertical through A origin ;
PLO about midway between upper base of P and LL or
nearer LL; total GR 20·29 ... ....... .. .......... ...... ..... ...... ... ... ...... 2
2a Op2 on level of ventral margin of orbit; PLO
markedly nearer LL than upper P base; SA01
well below line connecting VLO with SA02 .. ........... . B. fibulatum
2b OP2 well above level of ventral margin of orbit;
PLO midway between LL and upper P base;
SA01 on line connecting VLO with SA02 .... ..... .... ... B. pterotum
86.1 Benthosema fibulatum
(Gilbert & Cramer, 1897)
Myctophum fibulatum Gilbert & Cramer, 1897: 411, PI. 38, Fig. 2
(Kaiwi Channel, Hawaii). Benthosema fibulatum: Nafpaktitis &
Nafpaktitis, 1969: 12*; Kotthaus , 1972: 14* ; Gj0saeter & Beck, 1981:
255* ; Hulley , 1984: 66* .
D 12·14; A 18·20; P 14·17; GR (6·7)+(13·15); AO (5·6)+(4·5). Pos·
terodorsal opercular margin sharply angulate. Mature males with large
supracaudal and smaller infracaudalluminous gland; mature females with
single , small supracaudal and much smaller infracaudalluminous patch.
Attains 90 mm. High-oceanic, mesopelagic; upper 200 m
(night). Indian Ocean (18°N-200S) to 42°S in Agulhas Current; central Pacific (21°N-tO°S) and north of New Guinea.
86.1 Benthosema fibulatum: 1 .7 cm SL.
86: MYCfOPHIDAE (LANTERNFISHES)
86.2 Benthosema pterotum
(Alcock, 1890)
Scopelus (Myctophum) pterotus Alcock, 1890: 217 (18°30'N, 86°46'E) .
Benthosema pterotum: Kotthaus, 1972: 15*; Gj0saeter & Beck, 1981 :
255*.
D 13·14; A 17-22; P 14; GR (6-9)+(15-20); AO 6+(4-5) . Posterodorsal
opercular margin broadly rounded. Mature males and females usually
without caudal luminous glands; some males with indistinct supracaudal
luminous patch and some females with 1-2 poorly developed infracaudal
patches.
Attains 60 mm. High-oceanic, mesopelagic; 130 - 200 m
and 220 -300 m (day); 10- 200 m (night). Indian Ocean from
Arabian Sea to about 25°S off Mozambique; western North
Pacific.
86.2 Benthosema pterotum: adult female (after Bolin. 1939).
86.3 Benthosema suborbitale
(Gilbert, 1913)
Myctophum suborbitale Gilbert, 1913: 82 (Suruga Bay, Japan) .
Myctophum pterotum (non Alcock) : Smith , SFSA No. 197. Benthosema
fibulata (non Gilbert & Cramer): Grindley & Penrith, 1965: 282 . Benth·
osema suborbitale: Nafpaktitis & Nafpaktitis , 1969: 11* ; Kotthaus , 1972:
14*; Hulley, 1972: 220; 1981: 57*; 1984: 66.
D 12·14; A 16·18; P 14; GR3+(1O·1l); AO (5·7)+(4-6) . Posterodorsal
opercular margin broadly rounded. Mature males with single supracaudal
luminous gland; mature females with single infracaudalluminous gland ,
sometimes constricted.
Attains 39 mm. High-oceanic, mesopelagic; 375 - 750 m
(day); taken near surface and down to 125 m at night.
Broadly tropical distribution in Atlantic, Indian and Pacific
oceans, with extensions to 50 0 N and 50 0 S in western boundary
currents.
86.3 Benthosema suborbitale: 3 em SL.
285
line with last AOa; 4 (or more) Prc ... ... .......... ... Gymnoscopelus
27b AOa! not elevated; 2 or 3 Pol in a horizontal
line; 3 Prc .......... ... ...... ...... ... ............. ...... ....... . Notoscopelus
Genus Benthosema Goode & Bean, 1896
Maxilla expanded posteriorly, extending past orbit; A
base longer than Dbase. Dn and Vn small and poorly
defined; 5 PO; 4 VO; SAO series moderately to strongly
angulate; 1 Pol; AO series divided into AOa and AOp. Five
species; 3 in our area.
KEY TO SPECIES
la So present; SA03 about on vertical through
A origin ; PLO nearer upper base of P than
LL; total GR 13·15 ...... ............ ... ......... .... ..... .... . B. suborbitale
Ib So absent; SA03 well behind vertical through A origin ;
PLO about midway between upper base of P and LL or
nearer LL; total GR 20·29 ... ....... .. .......... ...... ..... ...... ... ... ...... 2
2a Op2 on level of ventral margin of orbit; PLO
markedly nearer LL than upper P base; SA01
well below line connecting VLO with SA02 .. ........... . B. fibulatum
2b OP2 well above level of ventral margin of orbit;
PLO midway between LL and upper P base;
SA01 on line connecting VLO with SA02 .... ..... .... ... B. pterotum
86.1 Benthosema fibulatum
(Gilbert & Cramer, 1897)
Myctophum fibulatum Gilbert & Cramer, 1897: 411, PI. 38, Fig. 2
(Kaiwi Channel, Hawaii). Benthosema fibulatum: Nafpaktitis &
Nafpaktitis, 1969: 12*; Kotthaus , 1972: 14* ; Gj0saeter & Beck, 1981:
255* ; Hulley , 1984: 66* .
D 12·14; A 18·20; P 14·17; GR (6·7)+(13·15); AO (5·6)+(4·5). Pos·
terodorsal opercular margin sharply angulate. Mature males with large
supracaudal and smaller infracaudalluminous gland; mature females with
single , small supracaudal and much smaller infracaudalluminous patch.
Attains 90 mm. High-oceanic, mesopelagic; upper 200 m
(night). Indian Ocean (18°N-200S) to 42°S in Agulhas Current; central Pacific (21°N-tO°S) and north of New Guinea.
86.1 Benthosema fibulatum: 1 .7 cm SL.
86: MYCfOPHIDAE (LANTERNFISHES)
86.2 Benthosema pterotum
(Alcock, 1890)
Scopelus (Myctophum) pterotus Alcock, 1890: 217 (18°30'N, 86°46'E) .
Benthosema pterotum: Kotthaus, 1972: 15*; Gj0saeter & Beck, 1981 :
255*.
D 13·14; A 17-22; P 14; GR (6-9)+(15-20); AO 6+(4-5) . Posterodorsal
opercular margin broadly rounded. Mature males and females usually
without caudal luminous glands; some males with indistinct supracaudal
luminous patch and some females with 1-2 poorly developed infracaudal
patches.
Attains 60 mm. High-oceanic, mesopelagic; 130 - 200 m
and 220 -300 m (day); 10- 200 m (night). Indian Ocean from
Arabian Sea to about 25°S off Mozambique; western North
Pacific.
86.2 Benthosema pterotum: adult female (after Bolin. 1939).
86.3 Benthosema suborbitale
(Gilbert, 1913)
Myctophum suborbitale Gilbert, 1913: 82 (Suruga Bay, Japan) .
Myctophum pterotum (non Alcock) : Smith , SFSA No. 197. Benthosema
fibulata (non Gilbert & Cramer): Grindley & Penrith, 1965: 282 . Benth·
osema suborbitale: Nafpaktitis & Nafpaktitis , 1969: 11* ; Kotthaus , 1972:
14*; Hulley, 1972: 220; 1981: 57*; 1984: 66.
D 12·14; A 16·18; P 14; GR3+(1O·1l); AO (5·7)+(4-6) . Posterodorsal
opercular margin broadly rounded. Mature males with single supracaudal
luminous gland; mature females with single infracaudalluminous gland ,
sometimes constricted.
Attains 39 mm. High-oceanic, mesopelagic; 375 - 750 m
(day); taken near surface and down to 125 m at night.
Broadly tropical distribution in Atlantic, Indian and Pacific
oceans, with extensions to 50 0 N and 50 0 S in western boundary
currents.
86.3 Benthosema suborbitale: 3 em SL.
285