TAXONOMIC STUDY OF TWO NEW GENERA OF FUSIFORM GREEN FLAGELLATES, TABRIS GEN. NOV. AND HAMAKKO GEN. NOV. (VOLVOCALES, CHLOROPHYCEAE)1

Authors

  • Takashi Nakada,

    1. Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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    • 2

      Author for correspondence: e-mail naktak@ttck.keio.ac.jp.

    • 3

      Present address: Institute for Advanced Biosciences, Keio University, 246-2 Mizukami, Kakuganji, Tsuruoka 997-0052, Japan.

  • Hisayoshi Nozaki

    1. Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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  • 1

    Received 18 April 2008. Accepted 13 October 2008.

  • 4

    Research Fellow of the Japan Society for the Promotion of Science.

Abstract

On the basis of LM, we isolated strains of two species of fusiform green flagellates that could be assigned to former Chlorogonium (Cg.) Ehrenb. One species, “Cg.”heimii Bourr., lacked a pyrenoid in its vegetative cells and required organic compounds for growth. The other was similar to Cg. elongatum (P. A. Dang.) Francé and “Cg.”acus Nayal, but with slightly smaller vegetative cells. Their molecular phylogeny was also studied based on combined 18S rRNA, RUBISCO LSU (rbcL), and P700 chl a-apoprotein A2 (psaB) gene sequences. Both species were separated from Chlorogonium emend., Gungnir Nakada and Rusalka Nakada, which were formerly assigned to Chlorogonium. They were accordingly assigned to new genera, Tabris Nakada gen. nov. and Hamakko (Hk.) Nakada gen. nov. as T. heimii (Bourr.) Nakada comb. nov. and Hk. caudatus Nakada sp. nov., respectively. Tabris is differentiated from other genera of fusiform green flagellates by its vegetative cells, which only have two apical contractile vacuoles and lack a pyrenoid in the chloroplast. Hamakko, on the other hand, is distinguishable by the fact that its pyrenoids in vegetative cells are penetrated by flattened thylakoid lamellae.

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