Phosphatized polar lobe-forming embryos from the Precambrian of southwest China.
In developing embryos of some extant spiralian animals, polar lobe formation is one of the symmetry-breaking mechanisms for segregation of maternal cytoplasmic substances to certain blastomeres and not others. Polar lobe formation leads to unique early cleavage morphologies that include trilobed, J-shaped, and five-lobed structures. Fossil embryos similar to modern lobeforming embryos are recognized from the Precambrian Doushantuo Formation phosphates, Weng'an, Guizhou Province, China. These embryos are abundant and form a developmental sequence comparable to different developing stages observed in lobe-forming embryos of extant spiralians. These data imply that lobe formation is an evolutionarily ancient process of embryonic specification.
Chen
Jun-Yuan
JY
Nanjing Institute of Geology and Paleontology, Institute of Evo/Developmental Biology, and State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, China. chenjy@nju.edu.cn
Bottjer
David J
DJ
Davidson
Eric H
EH
Dornbos
Stephen Q
SQ
Gao
Xiang
X
Yang
Yong-Hua
YH
Li
Chia-Wei
CW
Li
Gang
G
Wang
Xiu-Qiang
XQ
Xian
Ding-Chang
DC
Wu
Hung-Jen
HJ
Hwu
Yeu-Kuang
YK
Tafforeau
Paul
P
D000818:Animals; D000845:Annelida / Q000196:embryology; D005075:Biological Evolution; D001757:Blastomeres / Q000166:cytology; D002681:China; D004625:Embryo, Nonmammalian / Q000033:anatomy & histology* / Q000166:cytology; D047108:Embryonic Development; D005580:Fossils; D019015:Geologic Sediments; D007448:Invertebrates / Q000196:embryology*; D008974:Mollusca / Q000196:embryology; D010710:Phosphates; D010986:Platyhelminths / Q000196:embryology
D010710:Phosphates