title: Five Cyanophora (Cyanophorales, Glaucophyta) species delineated based on morphological and molecular data.
abstract: Cyanophora is an important glaucophyte genus of unicellular biflagellates that may have retained ancestral features of photosynthetic eukaryotes. The nuclear genome of Cyanophora was recently sequenced, but taxonomic studies of more than two strains are lacking for this genus. Furthermore, no study has used molecular methods to taxonomically delineate Cyanophora species. Here, we delimited the species of Cyanophora using light and electron microscopy, combined with molecular data from several globally distributed strains, including one newly established. Using a light microscope, we identified two distinct morphological groups: one with ovoid to ellipsoidal vegetative cells and another with dorsoventrally flattened or broad, bean-shaped vegetative cells containing duplicated plastids. Our light and scanning electron microscopy clearly distinguished three species with ovoid to ellipsoidal cells (C. paradoxa Korshikov, C. cuspidata Tos.Takah. & Nozaki sp. nov., and C. kugrensii Tos.Takah. & Nozaki sp. nov.) and two species with broad, bean-shaped cells (C. biloba Kugrens, B.L.Clay, C.J.Mey. & R.E.Lee and C. sudae Tos.Takah. & Nozaki sp. nov.) based on differences in cell shape and surface ornamentations of the vegetative cells under the field-emission scanning electron microscope. Molecular phylogenetic analyses of P700 chl a apoprotein A2 (psaB) genes and internal transcribed spacer (ITS) regions of nuclear ribosomal DNA (rDNA), as well as a comparison of secondary structures of nuclear rDNA ITS-2 and genetic distances of psaB genes, supported the delineation of five morphological species of Cyanophora.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa, 230-0045, Japan.
authors.forename: Mayuko
authors.initials: M
authors.lastname: Sato
authors.affiliation: RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa, 230-0045, Japan.
authors.forename: Kiminori
authors.initials: K
authors.lastname: Toyooka
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Matsuzaki
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kawafune
authors.affiliation: Department of Natural Science, Faculty of Science, Kochi University, 2-5-1 Akebono-cho, Kochi-shi, 780-8520, Japan.
authors.forename: Mai
authors.initials: M
authors.lastname: Kawamura
authors.affiliation: Graduate School of Integrated Arts and Sciences, Doctoral Course, Kuroshio Science, Kochi University, 2-5-1 Akebono-cho, Kochi-shi, 780-8520, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Okuda
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Nozaki
keywords: Cyanophora; Glaucophyta; field-emission scanning electron microscopy; freeze-fracture method; molecular phylogeny; morphology; new species; secondary structure of nuclear rDNA ITS-2; taxonomy; ultrastructure