title: Eoandromeda and the origin of Ctenophora.
abstract: The Ediacaran fossil Eoandromeda octobrachiata had a high conical body with eight arms in helicospiral arrangement along the flanks. The arms carried transverse bands proposed to be homologous to ctenophore ctenes (comb plates). Eoandromeda is interpreted as an early stem-group ctenophore, characterized by the synapomorphies ctenes, comb rows, and octoradial symmetry but lacking crown-group synapomorphies such as tentacles, statoliths, polar fields, and biradial symmetry. It probably had a pelagic mode of life. The early appearance in the fossil record of octoradial ctenophores is most consistent with the Planulozoa hypothesis (Ctenophora is the sister group of Cnidaria + Bilateria) of metazoan phylogeny.
authors.affiliation: Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China. tangfeng@cags.ac.cn
authors.forename: Feng
authors.initials: F
authors.lastname: Tang
authors.forename: Stefan
authors.initials: S
authors.lastname: Bengtson
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
authors.forename: Xun-lian
authors.initials: XL
authors.lastname: Wang
authors.forename: Chong-yu
authors.initials: CY
authors.lastname: Yin
mesh_terms: D000818:Animals; D037302:Ctenophora / Q000033:anatomy & histology / Q000145:classification / Q000235:genetics*; D005580:Fossils; D010802:Phylogeny