| Early preflexion larvae slender, becoming somewhat robust in postflexion stage; gut moderately long, nearly straight; head large, flattened; pectoral fin base aliform; much of early pigmentation lost; Br2 photophores form at about 9.0 mm; PO1 and PO5 first to form at transformation.
Distinguished from other myctophids with elliptical eyes by: broad head; eyes slightly stalked with conical choroid mass (narrow); early pectoral fin development, pectorals large with wing-shaped base; early pelvic fin development (unusual for myctophids); dorsal fin rays develop in finfold; slightly enlarged median finfold; pigment on paired fins.
Pigmentation:
Preflexion: by about 4.0 mm, ventrolateral pair just anterior to cleithra, 3-4 pairs laterally on gut, 2 dorsolateral pairs on terminal section of gut, up to 11 in a ventral median series extending from above preanal arch of gut to mid-postanal region; by 5.0 mm, a pair on anterior edge of lower jaw and peppering on pelvic fins; by 7.0 mm, up to 3 pairs on isthmus, cleithral pair lie vertically on cleithra, pair on ventrolateral region of hindbrain, pair at lower jaw tip (some specimens), series outlining dorsal margin of pectoral fin base, and some distally on pectoral fin rays; by end of stage, lateral gut an and postanal series lost.
Flexion-postflexion: by about 8.0 mm, series along ventral margin of pectoral fin base; bar on pectoral fin blade.
Sequence of fin development: pectorals, pelvics and caudal, anal, dorsal: pectoral fin base large and wing-shaped with supernumerary rays developing first. |
