EGG INFORMATION
Egg Diameter (min-max in mm): 0.92 - 1.04
Number of Oil Globules (min-max): 1
Oil Globule Diameter (min-max in mm): 0.26 - 0.28
Yolk: Segmented
Chorion: Smooth, clear
Egg/Embryo Pigment: none,
Pigment Diagnostics: Diagnostic Characters: Segmented yolk, secondary membrane inside chorion
LARVAE INFORMATION
Hatch Size (min-max in mm SL): 2.5
Preanal Length (%SL): <50 increasing with development to ~50%
Flexion Length (in mm SL): 10 - 11
1 Length at Transformation (in mm SL): >6 mm; body shrinks 2-3 mm, gut shortens, head deepens, and eyes become telescopic
Fin Development Sequence: Caudal and pectorals, dorsal and anal, pelvics
Larval Pigment Regions: In each developmental larval stage, pigment is present in the regions listed below
(click for
pigment regions)
Yolk-sac: none,
Preflexion: none,
Flexion: none,
Postflexion: none,
Juvenile: mouth, crown, nape, cheek, isthmus, dorsal gut, lateral gut, ventral gut, pectoral fin, mediolateral,
Pigment Diagnostics: Lack of pigment, especially none anterior of midbrain
Diagnostic Characters: See sternoptychid photophore figure 9. Elongate compressed body; photophores and sequence of development (~6-10 mm SL): lower OP, BR, posterior IV, anterior IV, posterior AC, anterior AC, OA, ORB, and VAV; SAB, PAN, AN, and SC photophores not in continuous row; postabdominal spines: in larvae >10-12 mm SL, anterior spine becomes thinner and elongated, bends under the posterior spines and the posterior spine gradually reduces and becomes spur-shaped; number of dorsal-fin rays (8), eye shape more cylindrical than other Argyropelecus spp., conical choroid tissue below eyes, 14-18 preanal myomeres before transformation, 11-14 after transformation; 37-38 total myomeres. Through early postflexion stage, preanal length usually will distinguish A. affinis and A. sladeni (shorter preanal length) from A. hemigymnus and A. lychnus (longer preanal length), and presence/absence of internal caudal peduncle pigment will distinguish A. affinis and A. lychnus (pigment present) from A. hemigymnus and A. sladeni (pigment absent).
