86: MYCTOPHIDAE (LANTERNFISHES)
8a Body slender, with dorsal and ventral profiles
parallel; PLO, PVO j and PVOz on same straight
horizontal line; 2 SAO; Prez above anterior
procurrent C ray, Prcj in front ............................. Krefftichthys
8a
8b Dorsal and ventral profiles not parallel; PLO slightly
above to well above PVO j; 3 SAO; Prcj above anterior
procurrent C ray, Prcz behind ............................................. 9
8b
PLO~. ~
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o
.. '''co 0
, '\.
PVO, PV02
PLQ"',I~
PVO, ..... ~ i
~
i
PV02
9a PLO in front of and slightly higher than PVO j;
PLO, PVOj and PVOz on somewhat angulate
line ......................................................... Protomyctophum
9b PLO almost directly above PVO j; PLO, PVO j
andPVOzformingatriangle ............................................. 10
lOa VOz elevated; posterodorsal margin of operculum
sharply rounded and serrate ................................ Metelectrona
lOb VOzlevel with rest of series or only slightly
raised; posterodorsal margin of operculum broadly
rounded and without serrations ............................... Electrona
11a PVO series horizontal, with PVO! not more than its own
diameter below level of PVOz; VOz elevated ........................ 12
lIb PVO series on an inclined line, with PVOj more than its
own diameter below level of PVOz; VO series level ................ 13
12a Prc horizontal, or with Prcz only very slightly
raised, lying more than 2 times its diameter below
LL; outer, posterior teeth in both jaws
broad·based and hooked .................................. Diogenichthys
12b Prez much higher than Prcl> lying at or less than its
diameter below LL; outer posterior teeth in both
jaws small and conical ........................................ Benthosema
13a Two Pol ........................................................... Hygophum
13b One Pol ....................................................................... 14
14a SAO series strongly angulate, with SAOj in
advance (seldom directly over) V03 ...... ........... Symbolophorus
14b SAO series in a straight or slightly angulate
line, with SAOj behind the vertical through V03 ...... Myctophum
15a POl> PVO j and PVOz on a straight ascending line;
VOl> VOz and V03 on a straight ascending line ..................... 16
15b POl> PVO j and PVOz not on a straight ascending line;
VOl> VOz and V03 not on a straight ascending line ................ 17
16a Dn and Vn present on head; supracaudal and
infracaudalluminous glands absent in both sexes ........... Diaphus
16b Dn present on head, Vn absent; supracaudal (males)
and infracaudal (females) luminous glands well
developed ......................................................... Lobianchia
17a Dn present .................................................................... 18
17b Dn absent ..................................................................... 24
284
18a Supracaudal and infracaudal glands large, singular and
bordered by heavy black pigment ....................................... 19
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18a
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18b Supracaudal and infracaudal glands consisting of a series
of overlapping scale-like structures, not bordered by
heavy black pigment . .. . . . .. . . . .. .. .. . . .. . . . .. . .. . .. .. . . . .. . ..... . . .. . . .. .. 20
18b
~~ j
-------------- i
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19a D origin behind vertical through outer base of
V; a large crescent of whitish tissue on rear lj of
iris; 1 SAO ................................................... Taaningichthys
19b D origin on or somewhat in advance of vertical
at outer base of V; no large crescent of whitish
tissue on rear lj of iris (Lampadena chavesi with
whitish crescent on dorsallj ofiris); 3 SAO ............. Lampadena
20a P04 not elevated; luminous scale-like structures
midventrally between bases of V and anus........... Ceratoscopelus
20b P04 highly elevated; no luminous scale-like structures
between bases of V and anus ............................................. 21
21a Patches of luminous tissue at bases of median and paired
fins .............................................................................. 22
21b No patches of luminous tissue at bases of median and
paired fins; luminous tissue (other than photophores)
restricted to supracaudal and infracaudal glands and
sometimes to base of adipose fin ........................................ 23
22a Only 3 Prc; crescent of whitish tissue on rear lj
of iris; posterodorsal margin of operculum
sharply pointed and rear margin markedly
concave ........................................................... Bolinichth ys
22b Four (sometimes more) Prc; no crescent of
whitish tissue on rear lj of iris; posterodorsal margin
of operculum broadly rounded, rear margin only
slightly concave ............................................... Lepidophanes
23a Four (rarely 5) VO, level or with VOz elevated;
opercular head of hyomandibula with small
dermal process ................................................ Lampanyctus
23b Five VO, with VOz or VOz and V03 elevated;
opercular head of hyomandibula without dermal
process ............................................................ Triphoturus
24a PVO horizontal; P03 and POs elevated ............. Lampanyctodes
24b PVO vertical; PO series level ............................................ 25
25a VOz elevated; 12-14 A rays...................................... Hintonia
25b VO series level; more than 17 A rays .................................. 26
26a "Secondary" photophores present on head and
body; 3-7 "primary" cheek photophores; 3 Pol
forming a right angle ......................................... Lampichthys
26b No "secondary" photophores on head and body;
no cheek photophores; 2 or 3 Pol, in horizontal
or subverticalline with last A Oa ........................................ 27
8a Body slender, with dorsal and ventral profiles
parallel; PLO, PVO j and PVOz on same straight
horizontal line; 2 SAO; Prez above anterior
procurrent C ray, Prcj in front ............................. Krefftichthys
8a
8b Dorsal and ventral profiles not parallel; PLO slightly
above to well above PVO j; 3 SAO; Prcj above anterior
procurrent C ray, Prcz behind ............................................. 9
8b
PLO~. ~
.'\
o
.. '''co 0
, '\.
PVO, PV02
PLQ"',I~
PVO, ..... ~ i
~
i
PV02
9a PLO in front of and slightly higher than PVO j;
PLO, PVOj and PVOz on somewhat angulate
line ......................................................... Protomyctophum
9b PLO almost directly above PVO j; PLO, PVO j
andPVOzformingatriangle ............................................. 10
lOa VOz elevated; posterodorsal margin of operculum
sharply rounded and serrate ................................ Metelectrona
lOb VOzlevel with rest of series or only slightly
raised; posterodorsal margin of operculum broadly
rounded and without serrations ............................... Electrona
11a PVO series horizontal, with PVO! not more than its own
diameter below level of PVOz; VOz elevated ........................ 12
lIb PVO series on an inclined line, with PVOj more than its
own diameter below level of PVOz; VO series level ................ 13
12a Prc horizontal, or with Prcz only very slightly
raised, lying more than 2 times its diameter below
LL; outer, posterior teeth in both jaws
broad·based and hooked .................................. Diogenichthys
12b Prez much higher than Prcl> lying at or less than its
diameter below LL; outer posterior teeth in both
jaws small and conical ........................................ Benthosema
13a Two Pol ........................................................... Hygophum
13b One Pol ....................................................................... 14
14a SAO series strongly angulate, with SAOj in
advance (seldom directly over) V03 ...... ........... Symbolophorus
14b SAO series in a straight or slightly angulate
line, with SAOj behind the vertical through V03 ...... Myctophum
15a POl> PVO j and PVOz on a straight ascending line;
VOl> VOz and V03 on a straight ascending line ..................... 16
15b POl> PVO j and PVOz not on a straight ascending line;
VOl> VOz and V03 not on a straight ascending line ................ 17
16a Dn and Vn present on head; supracaudal and
infracaudalluminous glands absent in both sexes ........... Diaphus
16b Dn present on head, Vn absent; supracaudal (males)
and infracaudal (females) luminous glands well
developed ......................................................... Lobianchia
17a Dn present .................................................................... 18
17b Dn absent ..................................................................... 24
284
18a Supracaudal and infracaudal glands large, singular and
bordered by heavy black pigment ....................................... 19
~~/~
18a
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18b Supracaudal and infracaudal glands consisting of a series
of overlapping scale-like structures, not bordered by
heavy black pigment . .. . . . .. . . . .. .. .. . . .. . . . .. . .. . .. .. . . . .. . ..... . . .. . . .. .. 20
18b
~~ j
-------------- i
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19a D origin behind vertical through outer base of
V; a large crescent of whitish tissue on rear lj of
iris; 1 SAO ................................................... Taaningichthys
19b D origin on or somewhat in advance of vertical
at outer base of V; no large crescent of whitish
tissue on rear lj of iris (Lampadena chavesi with
whitish crescent on dorsallj ofiris); 3 SAO ............. Lampadena
20a P04 not elevated; luminous scale-like structures
midventrally between bases of V and anus........... Ceratoscopelus
20b P04 highly elevated; no luminous scale-like structures
between bases of V and anus ............................................. 21
21a Patches of luminous tissue at bases of median and paired
fins .............................................................................. 22
21b No patches of luminous tissue at bases of median and
paired fins; luminous tissue (other than photophores)
restricted to supracaudal and infracaudal glands and
sometimes to base of adipose fin ........................................ 23
22a Only 3 Prc; crescent of whitish tissue on rear lj
of iris; posterodorsal margin of operculum
sharply pointed and rear margin markedly
concave ........................................................... Bolinichth ys
22b Four (sometimes more) Prc; no crescent of
whitish tissue on rear lj of iris; posterodorsal margin
of operculum broadly rounded, rear margin only
slightly concave ............................................... Lepidophanes
23a Four (rarely 5) VO, level or with VOz elevated;
opercular head of hyomandibula with small
dermal process ................................................ Lampanyctus
23b Five VO, with VOz or VOz and V03 elevated;
opercular head of hyomandibula without dermal
process ............................................................ Triphoturus
24a PVO horizontal; P03 and POs elevated ............. Lampanyctodes
24b PVO vertical; PO series level ............................................ 25
25a VOz elevated; 12-14 A rays...................................... Hintonia
25b VO series level; more than 17 A rays .................................. 26
26a "Secondary" photophores present on head and
body; 3-7 "primary" cheek photophores; 3 Pol
forming a right angle ......................................... Lampichthys
26b No "secondary" photophores on head and body;
no cheek photophores; 2 or 3 Pol, in horizontal
or subverticalline with last A Oa ........................................ 27