Osteichthyes
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Famiglia Myctophidae |
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Benthosema Goode & Bean, 1896
Ceratoscopelus Electrona Goode & Bean, 1896
Hygophum Bolin, 1939 |
Lampanyctus
Lobianchia Gatti, 1903
Myctophum
Symbolophorus Bolin & Wisner, 1959
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Dn: Dorso-nasale |
PO: Pettorali |
AOp: Anali posteriori |
Vn: Ventro-nasale |
VLO: Sopraventrali |
Prc: Precodali |
So: Suborbitale |
POL: Posterolaterale |
Gs: Ghiandola luminosa sopracodale |
Br: Branchiostegi |
AOa: Anali anteriori |
Gi: Ghiandola luminosa infracodale |
PLO: Soprapettorale |
SAO: Sopranali |
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PVO: Subpettorali |
VO: Ventrali |
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1a. Two Prc photophores > 21b. Three or more Prc (1 may be at or above lateral midline at base of caudal peduncle) or none in Taaningichthys paurolychnus > 122a. Four photophores (VLO, SAO3, Pol,Prc2) well above the midlateral line; specimens usually skinned and photophores often lost; small species, never over 2.5 cm - Notolychnus valdiviae2b. No photophores above lateral line > 33a. AO in a single uninterrupted series; Pol absent > 43b. AO divided into 2 groups, AOa and AOp; Pol present > 54a. PVO1-2 inclined, in line with PO1; interorbital wide; eye normal, pointing laterally Electrona risso 4b. PVO1-2 in an almost horizontal line, a line through them markedly above PO1; interorbital very narrow; eyes pointed upward, almost telescopic Protomyctophum arcticum 5a. Mouth terminal, snout not projecting; jaws short, extending less than 1/2 eye diameter behind orbit. > 6 5b. Mouth subterminal, snout projecting; jaws moderate, extending 1/2 eye diameter behind orbit >106a. PVO1-2 in a horizontal line; VO2 elevated >76b. PVO1-2 in an inclined line, with PVO2 usually more than 1 photophore diameter above PVO1; all VO level > 87a. Prc2 high, from 1 to 2 photophore diameters below, or on, midlateral line; teeth simple, never hooked Benthosema7b. Prc2 low, level with Prc1; outer dentary teeth flattened and hooked forward Diogenichthys atlanticus8a. Two Pol Hygophum8b. One Pol > 99a. SAO forming an almost right angle with SAO1 over or in advance of VO3 Symbolophorus 9b. SAO in an almost straight or slightly angled line with SAO1 well behind VO3 Myctophum 10a. Gill rakers absent Centrobranchus nigroocellatus10b. Gill rakers present >1111a. AOp 7 or fewer, at most 1 over anal base; anal-fin origin about under middle of dorsal-fin base Loweina11b. AOp 10 or more, with 5 to 7 over anal-fin base; anal-fin origin under end of dorsal-fin base Gonichthys cocco12a. Dn absent; VO and Pol never arranged as in 12b >1312b. Dn present; either 2 horizontal Pol near lateral line or VO1-3 on a straight ascending line with VO4-5 level > 1913a. Supra- and infracaudal glands single organs bordered by heavy jet-black pigment >1413b. Supra and infracaudal glands overlapping scale-like plates, never bordered by jet-black pigment >1514a. A large white crescent on posterior half of eye; dorsal-fin origin behind base of pelvic fin; only 1 SAO (at midbody) or none in T. paurolychnus Taaningichthys14b. No large white crescent on posterior half of eye; dorsal-fin origin over or slightly in front of pelvic fin; 3 SAO Lampadena15a. Luminous tissue restricted to caudal luminous glands and occasionally at base of adipose fin >1615b. Luminous tissue over base of anal or dorsal fins and on other portions of body > 1716a. Pectoral fin long, at least reaching SAO photophores, often to anterior anal fin. Lampanyctus16b. Pectoral fin rudimentary or short, seldom reaching PO4 (note that L. macdonaldi is the only Atlantic Lampanyctus with a short pectoral fin but it has 21 or more gill rakers vs. fewer than21 in all Nannobrachium) Nannobrachium17a. Three (2+1) Prc; a whitish crescent on posterior half of eye; luminous tissue above eyes in some species Bolinichthys17b. Four (3+1) Prc; eye without whitish crescent; no luminous tissue above eyes >1818a. PO4 elevated; VO2 elevated; no medial luminous tissue either at bases of pelvic fins or between pelvic fins and anal-fin origin; pectoral fin long, reaching adipose origin Lepidophanes18b. PO4 not elevated; VO only slightly arched; medial luminous tissue present at bases of pelvic fins or between pelvic fins and anal-fin origin; pectoral fins moderate, not reaching adipose fin Ceratoscopelus19a. VO1-5 level; both supra- and infracaudal glands present in both sexes; 2 horizontal Pol near lateral line Notoscopelus19b. VO1-3 on a straight, inclined, ascending line with VO4-5 level; no caudal glands (Diaphus) or only 1 caudal gland (Lobianchia); 1 Pol >2020a. Caudal glands absent; more than 1 pair of luminous glands on head (Ant, Dn, Vn, or So); usually a luminous scale at PLO Diaphus20b. Supracaudal (males) and infracaudal (females) well developed; 1 pair (Dn) of luminous organs on head; luminous scale at PLO absent Lobianchia |
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