part of
NF stage 1
Nieuwkoop and Faber stage 1, corresponding to an embryo of age 0 hr and having the following external morphological criteria: One cell stage, shortly after fertilization. Pigmentation darker ventrally than dorsally. Length: 1.4 - 1.5 mm.
UBERON:0000106
XAO:1000001
xenopus_developmental_stage
zygote
embryonic stage
NF stage