title: Raman spectra of a Lower Cambrian ctenophore embryo from southwestern Shaanxi, China.
abstract: 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.
authors.affiliation: Nanjing Institute of Geology and Palaeontology, Institute of Evo/Developmental Biology, Nanjing University, Nanjing 210093, China. chenjy@nju.edu.cn
authors.forename: Jun-Yuan
authors.initials: JY
authors.lastname: Chen
authors.forename: J William
authors.initials: JW
authors.lastname: Schopf
authors.forename: David J
authors.initials: DJ
authors.lastname: Bottjer
authors.forename: Chen-Yu
authors.initials: CY
authors.lastname: Zhang
authors.forename: Anatoliy B
authors.initials: AB
authors.lastname: Kudryavtsev
authors.forename: Abhishek B
authors.initials: AB
authors.lastname: Tripathi
authors.forename: Xiu-Qiang
authors.initials: XQ
authors.lastname: Wang
authors.forename: Yong-Hua
authors.initials: YH
authors.lastname: Yang
authors.forename: Xiang
authors.initials: X
authors.lastname: Gao
authors.forename: Ying
authors.initials: Y
authors.lastname: Yang
mesh_terms: D000818:Animals; D002681:China; D037302:Ctenophora / Q000648:ultrastructure*; D004625:Embryo, Nonmammalian / Q000648:ultrastructure; D005580:Fossils; D018613:Microscopy, Confocal; D013059:Spectrum Analysis, Raman