Comprehensive Description
(
Inglês
)
fornecido por Smithsonian Contributions to Zoology
Nannobrachium indicum
Lampanyctus sp.—Norman, 1939:29 [in part] [Gulf of Aden, Arabian Sea].
Lampanyctus sp. I.—Nafpaktitis and Nafpaktitis, 1969:42–43 [description and distribution].
Lampanyctus sp. II.—Nafpaktitis and Nafpaktitis, 1969:43–44, fig. 52 [description, figure].
Paralampanyctus sp.—Kotthaus, 1972b:29 [?in part] [southern tropical Indian Ocean].
Lampanyctus (Lampanyctus) niger.—Bekker, 1983:87–89, 198–200 [in part] [key, description, distribution].—[Not Fraser-Brunner, 1949.]
Lampanyctus sp. A.—Hulley, 1984a:63, 83–84, fig. 14 [description]; 1986c: 309–310, figs. 86, 88 [description, figure, off South Africa].
TYPE SPECIMENS.—Holotype: Female, 67 mm, ZMUC Dana sta 3912 II, 6°52′N, 79°30′E, 24 February 1929.
Paratypes: LACM 31-3411, 1 (50 mm); LACM 31-3451, 1 (56 mm); LACM 31–3461, 5 (26–65 mm); LACM 31–3551, 2 (63–67 mm); LACM 31–3582, 1 (37 mm); LACM 31-3612/7217, 3 (59–61 mm); LACM 31-3661, 2 (54–55 mm); LACM 31-3892, 1 (58 mm); USNM 268397, 3 (60–69 mm); ZMUC 35-776, 1 (104 mm); ZMUC 39-12, 18 (44–78 mm).
COMPARATIVE DIAGNOSIS.—Nannobrachium indicum (Figure 8) 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 14–17) (typically higher than in N. crypticum and N. gibbsi but lower than in N. atrum and N. nigrum) (Table A1) and by the number of luminous caudal-gland scales (1–3 / o–i+2–5), AO photophores (9–12), lateral line organs (29–32), and vertebrae (32–34) (typically lower than in all other species of Nannobrachium, except the same number of infracaudal luminous gland scales and vertebrae as in N. idostigma). In addition, it can be distinguished from all other Nannobrachium species by the combinations of characters in Table 1.
DESCRIPTION.—Counts are based on up to 29 specimens from the Indian Ocean and are given in Tables A1–A8. Counts for the holotype are D 14, A 17, P1 ?, GR 4+11, tooth patches 8, AO 4+7, SC/IC , LL 32, V15+18.
Proportions: Given in Table 7. Holotype measurements (in mm) as follows: SL 67, HD 11.4, PDD 10.0, CPD 6.6, CPL 14.6, PADL 13.6, PDL 31.4, PPL 27.4, PANL 40.3, PAL 10.9, HL 19.7 (damaged), UJL 14.3, SOL 4.1, ED 4.2 (damaged), SGL 3.9, IGS 5.4, IGEL 5.4, AFB 5.6, DFB 11.9, AF 6.7.
Fins: Origin of anal fin under middle of base of dorsal fin. Pectoral fin barely reaching vertical from VO3, its rays very weak and flexible. Base of adipose fin above end of anal-fin base, with adipose origin well in advance of end of anal-fin base.
Luminous Organs: PLO 1–2 photophore diameters below lateral line (about 2 diameters below in holotype). PO4 slightly higher than level of PVO2 and above or behind vertical from PO3 (PO4 slightly behind vertical from PO3 in holotype). VLO touching, or nearly touching, lateral line (VLO nearly touching lateral line in holotype). SAO2 position midway between VO4 and AOa1 variable, but frequently closer to AOa1 (SAO2 closer to AOa1 in holotype). SAO3 variably over AOa1 (SAO3 before vertical from AOa1 in holotype). AOa1 slightly depressed, and AO1–2 interspace enlarged. AOp1 behind end of anal-fin base. Prc well separated from AOp; Prc1–2 on an approximately horizontal line; Prc3–4 on a vertical or nearly vertical line, well behind Prc2. Supracaudal and infracaudal luminous scales well developed; infrequently with a single separated scale preceding the infracaudal gland. No secondary photophores found.
Size: Nannobrachium indicum is a small-bodied species of Nannobrachium, probably reaching a maximum size just over 100 mm.
Material: 57 (26–80 mm) specimens, excluding type material, were examined.
VARIATION.—Nannobrachium indicum is the only species of Nannobrachium evidently restricted to the Indian Ocean, where it is limited to the Equatorial Region (Figure 5). No geographic variation was noted in material examined from the extreme eastern and western ends of the range. The two specimens from off the east coast of South Africa, which Hulley (1984a, fig. 14) reported as Lampanyctus sp. A, appear to be fairly typical specimens of this species, although they were captured far to the south of any other specimens I examined. They may represent expatriates carried south by the Agulhas current system.
ETYMOLOGY.—The name is an adjective referring to the Indian Ocean.
The Regale Group
Two unique characters distinguish the species of this group: low position of the VLO on the side of the body and relatively robust pectoral-fin development. At a distance of three photophore diameters or more below the lateral line, the VLO is remote from the lateral line, always further than the PLO is from the lateral line. The pectoral fins are relatively strong and well developed, usually reaching beyond the pelvic-fin insertion, with moderately thick but rather flexible rays. Pectoral fins are better developed in this group than in any other Nannobrachium group. They are poorly developed, however, compared to the pectoral-fin development in most species of Lampanyctus, and accurate counts of pectoral-fin rays can only be made with difficulty. The species in the other Nannobrachium groups either lack pectorals or have pectorals with short, thick, and stiff rays, or they have pectorals with short, thin, and flexible rays.
Another character shared by species in the Regale group, but not unique to them, is the position of Prc3 below Prc4 but on a vertical from the anterior edge of Prc4.
These and other characters are compared in Table 1 for all the species groups of Nannobrachium.
The Regale group contains five species: N. regale (Gilbert, 1891), N. ritteri (Gilbert, 1915), N. idostigma (Parr, 1931), N. fernae (Wisner, 1971), and N. bristori, new species. Modal characters of all species in the Regale group are listed in Table A9.
- citação bibliográfica
- Zahuranec, Bernard J. 2000. "Zoogeography and systematics of the lanternfishes of the genus Nannobrachium (Myctophidae:Lampanyctini)." Smithsonian Contributions to Zoology. 1-69. https://doi.org/10.5479/si.00810282.607
