Stalked eyes with stalk length increasing to about 20% HL at about 9 mm, decreasing to about 12% at flexion stage and to 2-4% in post flexion stage; notochord tip pigment in early preflexion stage; hypaxial pigment series along entire body, epaxial series on posterior 33% of body; pigment series along hindgut.
Pigmentation:
Preflexion: below pectoral fin base lateral to liver; on terminal gut section; series of about 5 on lower trunk, increasing to about 12 at end of stage; pair on terminal gut increases to series extending forwards to entire hindgut; internal series on isthmus; series on epaxial myomeres above hindgut.
Flexion-postflexion: hypaxial series increases to about 1 per myomere from pectoral fin base to caudal fin; on hypural; on opercle; on upper and lower jaws; laterally on brain; postorbital and otic regions.
Sequence of fin development: caudal, anal, dorsal, pectorals and pelvics.
Distinguishing characters from other bathylagids with linear series of smaller melanophores: posterior gut melanophores larger and fewer; anterior region of gut lacks pigment; epaxial myomere series limited to posterior region; fin rays form in finfold, away from body margin.
Distinguished from B. bericoides by: presumably due to unavailability of small larvae, eye stalks are longer at comparable stages.
Distinguished from B. pacificus by: series of melanophores as opposed to isolated spots.
Also Ref. 265. |