Black Lantern Fish

9-10 tooth patches on the lower limb of the second gill arch; 10-13 AO photophores; 32-34 lateral line organs (Ref. 36121). Pectoral fins with extremely weak and flexible rays (Ref. 36121).

Dorsal spines (total): 0; Dorsal soft rays (total): 12 - 15; Analspines: 0; Analsoft rays: 14 - 18; Vertebrae: 33 - 37

Mesopelagic at 100-1000 m at night, 640-900 m during day (Ref. 58302). The two large specimens (19 and 21 cm SL) from near the Ogasawara Islands reported in Ref. 559 may represent another species (Ref. 36121).

Mesopelagic at 100-1000 m at night, 640-900 m during day (Ref. 58302). The two large specimens (19 and 21 cm SL) from near the Ogasawara Islands reported in Ref. 559 may represent another species (Ref. 36121).

Nannobrachium nigrum Günther, 1887

Nannobrachium nigrum Günther, 1887:199–200, pl. LII, fig. B [original description].—Gilbert, 1905:591 [description, Hawaiian Islands].—Herre, 1953:144 [original description listed].—Paxton, 1979:13 [holotype listed].

Myctophum (Lampanyctus) nigrum.—Brauer, 1906:242–243, 385 [in part] [distribution: Atlantic, Indian, and Pacific oceans].

Lampanyctus niger.—Parr, 1928:87 [key, similarities to L. ater].—Nafpaktitis, 1973:39–40 [figure, comparison with L. ater].—Parin, 1975:321, 325, 326 [?in part?] [tropical Pacific].—Clarke and Wagner, 1976:642 [?in part?] [vertical distribution].—Wisner, 1976:175–176 [description, distribution, figure].—Parin et al., 1977:122, 123, 165, 166 [in part] [western Pacific].—Nafpaktitis et al., 1977:204–206 [discussion, figure of holotype].—Clarke, 1978: 499–502 [feeding patterns]; 1983a:327, 328, 332 [abundance estimates]; 1983b:205–206 [in part?] [sex ratio, size]; 1987:65 [central Pacific biogeography].—Chen, 1983:199 [?in part] [South China Sea] [fide J. Paxton].—Huang and Yang, 1983:234 [?in part] [Dongsha Islands, South China Sea] [fide J. Paxton].—Fujii, 1984:69, pl. 66-M [?in part] [description, distribution].—Cheng and Zheng, 1987, unpaginated [?in part] [China records] [fide J. Paxton].—Kailola, 1987:103 [?in part] [Solomon Sea].—Yang et al., 1996, unpaginated [?in part] [Nansha Islands, northeast South China Sea] [fide J. Paxton].

Lampanyctus (Lampanyctus) niger.—Fraser-Brunner, 1949:1085 [in part] [illustrated key].—Bekker, 1983:87–89, 198–200 [in part] [key, description, distribution].

Paralampanyctus niger.—Kotthaus, 1972a: 14 [designated genotype].

Lampanyctus niger (Form B).—Clarke, 1973:416–418 [ecology north of Hawaii].

COMPARATIVE DIAGNOSIS.—Nannobrachium nigrum (Figure 4) can be distinguished from the other species of the Nigrum group and from N. crypticum in the Achirus group primarily by its gill-raker count (total 15–18) and number of tooth patches on the lower limb of the second gill arch (9–10) (both higher than in N. gibbsi, N. indicum, and N. crypticum). It can be distinguished from N. atrum by the lower number of AO photophores (10–13), anal-fin rays (14–18), lateral line organs (32–34), and vertebrae (33–37) and by having the SAO series farther back than in N. atrum (Table 3). It can be distinguished from all other species of Nannobrachium by the combination of characters in Table 1.

DESCRIPTION.—Counts are based on up to 31 specimens from the Pacific Ocean and are given in Tables A1–A8.

Proportions: Given in Table 2.

Fins: Origin of anal fin behind vertical from middle of base of dorsal fin. Pectoral fins not reaching beyond vertical from PO3, with extremely weak and flexible rays. Adipose-fin base above end of anal-fin base, with adipose origin usually only slightly before end of anal-fin base.

Luminous Organs: PLO 1–3 photophore diameters below lateral line. PO4 slightly higher than level of PVO2 or on same level and above or slightly behind vertical from PO3. VLO less than one photophore diameter below, frequently nearly touching, lateral line. SAO2 closer to AOa1 than to VO4 or equidistant from VO4 and AOa1. SAO3 approximately above AOa1. AOa1 slightly depressed and AOa1–2 interspace enlarged. AOp1 at or behind end of anal-fin base. Prc well separated from AOp; Prc1–2 on horizontal line or Prc2 slightly below level of Prc1; Prc3–4 on vertical or nearly vertical line, well behind Prc2. Supracaudal and infracaudal scales well developed, infrequently with a single, or even two (found once), separated luminous scales preceding the solid infracaudal gland. No secondary photophores found.

N. atrum N. nigrum

VLO above pelvic-fin base or above origin of pelvic fin VLO at end of pelvic-fin base or behind vertical from pelvic-fin base

PO4 tends to be above PO3 or slightly anterior to vertical from PO3 PO4 above or slightly posterior to vertical from PO3

SAO3 tends to be well before vertical from AOa1 SAO3 slightly before vertical from AOa1 or on vertical (sometimes slightly behind)

SAO2 tends to be closer to VO4 than to AOa1 SAO2 tends to be equidistant or closer to AOa1

Pol under adipose-fin base—usually under center of adipose-fin base Pol under origin to center of adipose-fin base

Line through VLO and SAO1 tends to pass through VO3 or slightly behind it—usually well before VO4 VLO-SAO1 line passes through VO4 or slightly behind it—as far as midway between VO4 and AOa1

Size: The largest specimen examined was 111 mm. Previously the maximum size for this species was reported by Clarke (1973) as being less than 90 mm for a specimen given as L. niger (Form B) from north of Hawaii.

Material: 1,798 (13–111 mm) specimens were examined, including the holotype, 103 mm, BMNH 1887.12.7:219, collected south of the Philippines in 1875 by H.M.S. Challenger.

VARIATION.—Nannobrachium nigrum is restricted to the tropical Pacific Ocean, primarily the western and central portions, and to the extreme eastern tropical Indian Ocean (Figure 5). No consistent differences in frequencies of meristic characters were found between specimens from the central and western Pacific and those from the eastern Indian Ocean; however, a few differences in photophore positions were noted. Specimens from north of Hawaii tended to have the VLO photophore behind a vertical from the end of the pelvic-fin base more often than did specimens from the western Pacific. In addition, those from around Hawaii more frequently had the SAO2 equidistant between the VO4 and AOa1, whereas western Pacific specimens commonly had the SAO2 closer to the AOa1 than to the VO4.

One 65 mm specimen from off New Caledonia (ORSTOM, collection number FAB 22) had such a high gill-raker count (6 + 14, left side, 5 + 14, right side + 10 tooth patches) that for some time it was seriously thought to represent another new species; however, photophore characters that could be checked were most similar to N. nigrum, although the SAO arrangement in this specimen somewhat resembled that of N. atrum. In addition, four specimens from various locations in the southwest Pacific proved to have a mixture of typical and high gill-raker counts (6+14, 1 count; 6+13, 2 counts; 5+13, 3 counts; 5+12, 2 counts). These extremely high counts were not entered in either Tables A1 or A3. Unfortunately, these specimens were in a poorer condition than the original 65 mm specimen. The interim conclusion, therefore, is to consider these specimens examples of intraspecific variability.

Fujii (1984:69) discussed the distribution of this species and gave a description based on two large specimens taken by mid- water trawl near the Ogasawara Islands (∼27°N, 143°E). Although his general discussion undoubtedly dealt with this species, the two above-mentioned specimens are almost certainly a different species because of their large size (“SL 19, 21 cm,” which is twice as large as the largest specimens I examined), high dorsal-fin ray, anal-fin ray, and AO counts, Pol “well in advance of origin of adipose fin” (rather than below adipose-fin base, see Table 3), and lower VLO position relative to the lateral line (frequently nearly touching the lateral line in N. nigrum). The identification of the two specimens is problematical; the large size and the Pol and VLO positions suggest N. lineatum as a possibility, but the dorsal-fin ray, anal-fin ray, and AO counts are too low for the ranges I recorded for Indo-Pacific specimens of N. lineatum (Table A10).

廣泛分布於太平洋海域，北自日本，南至菲律賓，東至加州及智利等。臺灣則發現於西南部、東部及東沙群島等周邊水域。

一般以底拖網捕獲，不具食用經濟價值，通常做為下雜魚用。

體細長，側扁，後部略細。頭略大。吻短，前端突出。眼大。口大，上頜骨狹長而延伸至前鰓蓋後緣，末端不擴大；上下頜、腭骨均具齒帶，鋤骨無齒。體被大而薄圓鱗，易脫落；側線平直。背鰭單一，位於體中部，具軟條15-16，後部另具一脂鰭；臀鰭基底長於背鰭基底，具軟條18-19；胸鰭短，末端不達腹鰭基底，軟條數12；尾鰭叉形，尾鰭副鰭條堅硬而呈棘狀。各部位之發光器位置於下：鼻部腹位發光器(Vn)小而圓形；鰓蓋位發光器(Op)2個，位於前鰓蓋後緣下方，Op1較Op2小，均在眼眶下緣縱線之下；胸鰭上方發光器(PLO)1個，緊臨側線下緣；胸鰭下方發光器(PVO)2個，PVO1在PVO2的略後下方；胸部發光器(PO)5個，PO4位置昇高；腹部發光器(VO)4個，水平排列；腹鰭上位發光器(VLO)位於側線下緣；臀鰭上方發光器(SAO)3個，三者排列呈鈍角狀，SAO3緊臨側線；體後側位發光器(Pol)2個，在脂鰭下方，Pol2緊臨側線下緣；臀鰭前部發光器(AOa)5-7個，幾呈水平排列；臀鰭後部發光器(AOp)6-7個，沿尾柄腹側排列；尾鰭前位發光器(Prc)4個，前三個略呈弧形排列，Prc1位於AOp後，但不相連，Prc4則在側線下緣。尾部發光腺SUGL約具2-3個及INGL約具3-5個小覆瓦狀發光鱗。以前所記載之黑體珍燈魚(/Lampanyctus niger/)為本種之同種異名。

大洋性中層巡游魚類，具日夜垂直分布習性，白天一般棲息深度可達450-2,754公尺左右，晚上則上游至水深50-275公尺附近處覓食，以小蝦等甲殼類為食。