Skip to main content

Table 1 Embryonic development stages of Inimicus japonicus at 21°C

From: Ontogenesis from embryo to juvenile and salinity tolerance of Japanese devil stinger Inimicus japonicus during early life stage

Main stages Substages Time (h:min) Description Figure
Zygote 2-cell stage 0:23 First cleavage, blastodisc divided via meridional cleavage to form two equal cells 1a
  4-cell stage 0:32 Second cleavage, dividing the blastodisc into 4 blastomeres 1b
  8-cell stage 0:40 Third cleavage, 2 x 4 array of blastomeres 1c
  16-cell stage 1:02 Fourth cleavage, 16 blastomeres can be seen 1d
  32-cell stage 1:35 Fifth cleavage, 2 regular tiers (horizontal rows) of blastomeres, sometimes in 4 x 8 array 1e
  64-cell stage 2:05 Sixth cleavage, 64 blastomeres were ranked irregularly 1f
  Morula stage 4:05 The blastomeres were still distinct but the number of blastomeres can not be counted 1g
Blastula Early blastula stage 6:30 The blastomeres were no longer distinguishable, the blastocoel began to form, and endoderm germ layer appeared 1h
  Late blastula stage 9:40 Epibolic cells increased, the archenteron can be seen, endoderm germ layer invaginated and the ectoderm layer formed 1i
Gastrula Early gastrula stage 11:36 Blastoderm cells begin to spread over the yolk, and blastoderm remains uniform in thickness 1j
  Mid gastrula stage 13:45 Germ ring epiboled 1/2 of yolk sac, embryonic shield visible from animal pole 1k
  Late gastrula stage 15:00 75% coverage of the yolk cell by the blastoderm, dorsal side distinctly thicker; epiblast, hypoblast, evacuation zone visible 1l
Neurula embryoid body formation 19:47 The prototype of the neural plate appeared, head part uplifted, yolk plug exposed, pigments on the embryonic shield and yolk sac can be seen 1m
Pharyngula Formation of optic vesicle 22:23 On both sides of the head, a pair of kidney-shaped protrusions can be seen 1n
  Appearance of myomere 25:46 Embryoid surrounded the yolk sac, in the center of the embryoid, 8–11 myomeres can be seen. 1o
  Muscular effect 38:35 Embryo begins to spin frequently, heart beat 70-75/min 1p
  Pre-hatching stage 42:45 The embryo shows conspicuous muscular contractions 1q
Hatching newly hatched larva 44:05 General transparent, floating on the water surface 1r