title: DESCRIPTION OF TWO NEW MONOECIOUS SPECIES OF VOLVOX SECT. VOLVOX (VOLVOCACEAE, CHLOROPHYCEAE), BASED ON COMPARATIVE MORPHOLOGY AND MOLECULAR PHYLOGENY OF CULTURED MATERIAL(1).
abstract: Species of Volvox sect. Volvox (Volvocaceae, Chlorophyceae) are unique because they have thick cytoplasmic bridges between somatic cells and spiny-walled zygotes. This section is taxonomically important because the genus Volvox is polyphyletic. However, taxonomic studies of species in Volvox sect. Volvox have not been carried out on cultured material. Here, we performed a taxonomic study of monoecious species of Volvox sect. Volvox based on the comparative morphology and molecular phylogeny of chloroplast genes and the internal transcribed spacer (ITS) regions of nuclear rDNA using various strains originating from Japan and two preserved strains from the USA. The strains were clearly divided into four species, V. globator L., V. barberi W. Shaw, V. kirkiorum sp. nov., and V. ferrisii sp. nov., on the basis of differences in numbers of zygotes (eggs) in the sexual spheroids, form of zygote wall, and somatic cell shape. Sequences for ITS of nuclear rDNA resolved that the two new species have phylogenetic positions separated from V. globator, V. barberi, V. capensis F. Rich et Pocock, and V. rousseletii G. S. West UTEX 1862 within Volvox sect. Volvox.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, JapanInstitute for Advanced Biosciences, Keio University, 246-2 Mizukami, Kakuganji, Tsuruoka, Yamagata, 997-0052, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Nanako
authors.initials: N
authors.lastname: Isaka
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, JapanInstitute for Advanced Biosciences, Keio University, 246-2 Mizukami, Kakuganji, Tsuruoka, Yamagata, 997-0052, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kawai-Toyooka
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, JapanInstitute for Advanced Biosciences, Keio University, 246-2 Mizukami, Kakuganji, Tsuruoka, Yamagata, 997-0052, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, 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, Hongo, Bunkyo-ku, Tokyo 113-0033, JapanInstitute for Advanced Biosciences, Keio University, 246-2 Mizukami, Kakuganji, Tsuruoka, Yamagata, 997-0052, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakada
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, JapanInstitute for Advanced Biosciences, Keio University, 246-2 Mizukami, Kakuganji, Tsuruoka, Yamagata, 997-0052, JapanDepartment of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Nozaki
keywords: Chlorophyceae; Volvocaceae; Volvox ferrisii sp. nov.; Volvox kirkiorum sp. nov.; Volvox sect. Volvox; cultures; molecular phylogeny; morphology; taxonomy