86: MYCfOPHIDAE (LANTERNFISHES)
2b Vn elongate, but shorter than horizontal diameter of
pupil; So in advance of vertical through rear margin of
pupil; luminous scale at PLO present ................................... 4
3a HD less than 4 times in SL; ED and CPD less
than 8 times in SL ...................................... D. brachycephalus
3b HD more than 4 times in SL; ED and CPD 8 or
more times in SL ............................................ D. richardsoni
4a Vn and So about equal in size, roundish or oval,
small, about >3 to Yz size of general body
photophore, and widely separated from each
other; body photophores placed low, very large
and separated by narrow spaces, those between
AO series equal to about Yz photophore-diameter .... D. anderseni
4b Vn elongate, much longer than roundish/oval So;
body photophores moderate in size, those of AO series
separated by spaces greater than Yz photophore-diameter
5
5a AOa! elevated ................................................................ 6
5b AOa series level or AOa! only slightly raised ......................... 8
6a Vn longer than distance between Vn and So;
operculum with straight, horizontal dorsal
margin, rear margin deeply concave; lower GR
broad-based and leaf-like ........................................ D. mol/is
6b Vn shorter than distance between Vn and So; operculum
with convex dorsal margin, rear margin slightly concave;
lower GR slender and lath-like ........................................... 7
7a Body photophores widely spaced, from at least 1.5
(AOa and AOp) to at least 2.5 (VO) photophorediameters apart; SAO) and Pol their diameter or
less below LL; upper jaw less than 17.5% SL .............. D. fulgens
7b Body photophores not widely spaced, from 1 (AOa
and AOp) to 2 (VO) photophore-diameters apart
or less; SAO) and Pol more than their diameter
below LL; upper jaw 18.5% SL or more ..................... D. aliciae
8a Vn not longer than distance between Vn and So;
operculum with prominent lobe posterodorsally; CPD
less than 1.5 times in CPL ......................................... D. parri
8b Vn much longer than distance between Vn and So;
operculum without prominent lobe posterodorsally;
CPD more than 1.5 times in CPL ........................................ 9
9a Prc continuous with AOp, so that distance Prc]"Prc)
is greater than AOp-Prc! interspace; C peduncle
elongate and narrow; anterior margin of lower GR
of 1st arch fleshy .................................................. D. subtilis
9b Prc separated from AOp; distance Prc!-Prc) equal to
or shorter than AOp-Prc! interspace; C peduncle normal;
anterior margin of lower GR of 1st arch not fleshy ................. 10
lOa Total GR 16-20; luminous scale at PLO striated
posteroventrally .................................................... D. meadi
lOb Total GR 22-28; luminous scale at PLO mottled ........ D. hudsoni
11a Dn small (better developed in males than in females) and
directed anterolaterally; Vn larger than Dn, at anteroventral
aspect of orbit usually extending dorsally along front margin
of orbit to Dn ................................................................ 12
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288
11b Dn ranging in size from smaller than body photophore to
much larger than nasal rosette, in more or less deep recess
and directed forward; Vn may be (i) restricted to ventral
aspect of orbit, (ii) restricted to anteroventral aspect of orbit,
(iii) extend dorsally to reach Dn, or (iv) spread over most
of entire area of snout ..................................................... 18
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•
11b
12a Vn round and small, half the size of general body
photophore, completely separated from Dn and
located at ventral margin of orbit on, or slightly in
advance of, vertical through front margin of pupil;
PLO in advance of vertical through upper base of P,
about 1-2 photophore-diameters below LL; SAO
series markedly angulate ..................................... D. dumerilii
12b Vn at anteroventral aspect of orbit, somewhat larger than
Dn and connected to Dn by thin streak of luminous tissue,
extending between eye and nasal apparatus; PLO on or
behind vertical through upper base of P, more than 2
photophore-diameters below LL; SAO series not or only
slightlyangulate ............................................................. 13
13a Total GR 13-15 ........................................... D. problematicus
13b Total GR more than 15 .................................................... 14
14a SAO! in line with V04 and V05 or nearly so; SAO)
and Pol about one photophore-diameter below LL,
adult males with well-developed Ant ........................ D. jenseni
14b SAO! not in line with V04 and V05; SAO) and Pol in contact
with or immediately below LL ........................................... 15
15a PLO nearer LL than to upper base of P ................... D. garmani
15b PLO nearer upper base of P than to LL (rarely midway) ......... 16
16a D 4 times or less in SL; V not reaching A origin;
Prc4 about 2 photophore-diameters below LL;
AOa 2 -AOa) interspace usually not enlarged; both
Dn and Vn greatly enlarged in adult males, with Dn
larger than Vn ................................................ D. malayanus
16b D more than 4 times in SL; V extending at least to A origin;
AOa 2 -AOa) interspace usually enlarged; Vn subequal to
much larger than Dn ....................................................... 17
17a Distance between VLO and V base 1.5-2.0 times
larger than distance between VLO and LL; AOa!
directly over or, usually, behind AOa 2 ; Vn about
equal in size to Dn (slightly larger than Dn in adult
males); D origin behind vertical through outer base
of V .......... ...................................................... D. signatus
17b VLO midway between base of V and LL or slightly
higher; AOa! directly over, or slightly in front of
AOa 2 ; Vn larger than Dn, especially in adult males;
D origin on or slightly in advance of vertical through
outer base of V ................................................... D. nielseni
18a Vn widely separated from Dn, confined to ventral or
anteroventral aspect of orbit but connected to Dn by a strand
of dark tissue along front margin of orbit ............................. 19
18b Vn extending dorsally between front margin of orbit and
nasal apparatus, to make contact with or become confluent
with Dn ........................................................................ 21
19a SAO! well above level of V05; maxilla extends less
than an eye diameter past orbit .............................. D. taaningi
2b Vn elongate, but shorter than horizontal diameter of
pupil; So in advance of vertical through rear margin of
pupil; luminous scale at PLO present ................................... 4
3a HD less than 4 times in SL; ED and CPD less
than 8 times in SL ...................................... D. brachycephalus
3b HD more than 4 times in SL; ED and CPD 8 or
more times in SL ............................................ D. richardsoni
4a Vn and So about equal in size, roundish or oval,
small, about >3 to Yz size of general body
photophore, and widely separated from each
other; body photophores placed low, very large
and separated by narrow spaces, those between
AO series equal to about Yz photophore-diameter .... D. anderseni
4b Vn elongate, much longer than roundish/oval So;
body photophores moderate in size, those of AO series
separated by spaces greater than Yz photophore-diameter
5
5a AOa! elevated ................................................................ 6
5b AOa series level or AOa! only slightly raised ......................... 8
6a Vn longer than distance between Vn and So;
operculum with straight, horizontal dorsal
margin, rear margin deeply concave; lower GR
broad-based and leaf-like ........................................ D. mol/is
6b Vn shorter than distance between Vn and So; operculum
with convex dorsal margin, rear margin slightly concave;
lower GR slender and lath-like ........................................... 7
7a Body photophores widely spaced, from at least 1.5
(AOa and AOp) to at least 2.5 (VO) photophorediameters apart; SAO) and Pol their diameter or
less below LL; upper jaw less than 17.5% SL .............. D. fulgens
7b Body photophores not widely spaced, from 1 (AOa
and AOp) to 2 (VO) photophore-diameters apart
or less; SAO) and Pol more than their diameter
below LL; upper jaw 18.5% SL or more ..................... D. aliciae
8a Vn not longer than distance between Vn and So;
operculum with prominent lobe posterodorsally; CPD
less than 1.5 times in CPL ......................................... D. parri
8b Vn much longer than distance between Vn and So;
operculum without prominent lobe posterodorsally;
CPD more than 1.5 times in CPL ........................................ 9
9a Prc continuous with AOp, so that distance Prc]"Prc)
is greater than AOp-Prc! interspace; C peduncle
elongate and narrow; anterior margin of lower GR
of 1st arch fleshy .................................................. D. subtilis
9b Prc separated from AOp; distance Prc!-Prc) equal to
or shorter than AOp-Prc! interspace; C peduncle normal;
anterior margin of lower GR of 1st arch not fleshy ................. 10
lOa Total GR 16-20; luminous scale at PLO striated
posteroventrally .................................................... D. meadi
lOb Total GR 22-28; luminous scale at PLO mottled ........ D. hudsoni
11a Dn small (better developed in males than in females) and
directed anterolaterally; Vn larger than Dn, at anteroventral
aspect of orbit usually extending dorsally along front margin
of orbit to Dn ................................................................ 12
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288
11b Dn ranging in size from smaller than body photophore to
much larger than nasal rosette, in more or less deep recess
and directed forward; Vn may be (i) restricted to ventral
aspect of orbit, (ii) restricted to anteroventral aspect of orbit,
(iii) extend dorsally to reach Dn, or (iv) spread over most
of entire area of snout ..................................................... 18
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11b
12a Vn round and small, half the size of general body
photophore, completely separated from Dn and
located at ventral margin of orbit on, or slightly in
advance of, vertical through front margin of pupil;
PLO in advance of vertical through upper base of P,
about 1-2 photophore-diameters below LL; SAO
series markedly angulate ..................................... D. dumerilii
12b Vn at anteroventral aspect of orbit, somewhat larger than
Dn and connected to Dn by thin streak of luminous tissue,
extending between eye and nasal apparatus; PLO on or
behind vertical through upper base of P, more than 2
photophore-diameters below LL; SAO series not or only
slightlyangulate ............................................................. 13
13a Total GR 13-15 ........................................... D. problematicus
13b Total GR more than 15 .................................................... 14
14a SAO! in line with V04 and V05 or nearly so; SAO)
and Pol about one photophore-diameter below LL,
adult males with well-developed Ant ........................ D. jenseni
14b SAO! not in line with V04 and V05; SAO) and Pol in contact
with or immediately below LL ........................................... 15
15a PLO nearer LL than to upper base of P ................... D. garmani
15b PLO nearer upper base of P than to LL (rarely midway) ......... 16
16a D 4 times or less in SL; V not reaching A origin;
Prc4 about 2 photophore-diameters below LL;
AOa 2 -AOa) interspace usually not enlarged; both
Dn and Vn greatly enlarged in adult males, with Dn
larger than Vn ................................................ D. malayanus
16b D more than 4 times in SL; V extending at least to A origin;
AOa 2 -AOa) interspace usually enlarged; Vn subequal to
much larger than Dn ....................................................... 17
17a Distance between VLO and V base 1.5-2.0 times
larger than distance between VLO and LL; AOa!
directly over or, usually, behind AOa 2 ; Vn about
equal in size to Dn (slightly larger than Dn in adult
males); D origin behind vertical through outer base
of V .......... ...................................................... D. signatus
17b VLO midway between base of V and LL or slightly
higher; AOa! directly over, or slightly in front of
AOa 2 ; Vn larger than Dn, especially in adult males;
D origin on or slightly in advance of vertical through
outer base of V ................................................... D. nielseni
18a Vn widely separated from Dn, confined to ventral or
anteroventral aspect of orbit but connected to Dn by a strand
of dark tissue along front margin of orbit ............................. 19
18b Vn extending dorsally between front margin of orbit and
nasal apparatus, to make contact with or become confluent
with Dn ........................................................................ 21
19a SAO! well above level of V05; maxilla extends less
than an eye diameter past orbit .............................. D. taaningi