Raman spectra of a Lower Cambrian ctenophore embryo from southwestern Shaanxi, China.
The Early Cambrian (approximately 540 million years old) Meishucun fossil assemblage of Ningqiang County (Shaanxi Province), China, contains the oldest complex skeletonized organisms known in the geological record. We here report the finding in this assemblage of an exquisitely preserved late-stage embryo of a ctenophore ("comb jelly"), its fine structure documented by confocal laser scanning microscopy and shown by Raman spectroscopy to be composed of carbonaceous kerogen permineralized in apatite. In its spheroidal morphology, the presence of eight comb rows and the absence of tentacles, this embryo resembles an adult ctenophore (Maotianoascus octonarius) known from the immediately younger Chengjiang fauna of Yunnan, China. The oldest ctenophore and the only embryonic comb jelly known from the fossil record, this exceptionally well preserved specimen provides important clues about the early evolution of the phylum Ctenophora and of metazoans in general.
Chen
Jun-Yuan
JY
Nanjing Institute of Geology and Palaeontology, Institute of Evo/Developmental Biology, Nanjing University, Nanjing 210093, China. chenjy@nju.edu.cn
Schopf
J William
JW
Bottjer
David J
DJ
Zhang
Chen-Yu
CY
Kudryavtsev
Anatoliy B
AB
Tripathi
Abhishek B
AB
Wang
Xiu-Qiang
XQ
Yang
Yong-Hua
YH
Gao
Xiang
X
Yang
Ying
Y
D000818:Animals; D002681:China; D037302:Ctenophora / Q000648:ultrastructure*; D004625:Embryo, Nonmammalian / Q000648:ultrastructure; D005580:Fossils; D018613:Microscopy, Confocal; D013059:Spectrum Analysis, Raman