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Testudodinium gen. nov. (Dinophyceae), a new genus of sand-dwelling dinoflagellates formerly classified in the genus Amphidinium

Authors

  • Takeo Horiguchi,

    Corresponding author
    1. Department of Natural History Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan
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  • Maiko Tamura,

    1. Department of Natural History Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan
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    • Present addresses: Okinawa Institute of Science and Technology, Onna, Okinawa 904-0495, Japan;

  • Kazuhito Katsumata,

    1. Department of Natural History Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan
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    • DuPont-Mitsui Fluorochemicals Co., Ltd., Shimizu, Shizuoka 424-8631, Japan.

  • Aika Yamaguchi

    1. Department of Natural History Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan
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  • Communicating Editor: M. Hoppenrath.

Email: horig@mail.sci.hokudai.ac.jp

SUMMARY

A new genus of sand-dwelling photosynthetic dinoflagellate, Testudodinium Horiguchi, Tamura, Katsumata et A. Yamaguchi is proposed based on Testudodinium testudo (Herdman) Horiguchi, Tamura, Katsumata, et A. Yamaguchi comb. nov. (Basionym: Amphidinium testudo Herdman) and a new species in this new genus, Testudodinium maedaense Katsumata et Horiguchi sp. nov. is described. Amphidinium corrugatum is also transferred to this genus, making a new combination T. corrugatum (Larsen et Patterson) Horiguchi, Tamura et A. Yamaguchi. These three species are similar to the members of the genus Amphidinium in having an extremely small episome and a dorsoventrally flattened cell body. They are, however, distinguished from the genus Amphidinium seusu stricto by the possession of a distinct longitudinal furrow in the middle of ventral side of the episome. Phylogenetic trees based on small subunit (SSU) rDNA revealed that all three of these Testudodinium species formed a robust clade and, although statistical support is not high, the tree suggests Testudodinium clade is not closely related to Amphidinium seusu stricto clade. The morphological differences together with molecular data support the establishment of a new genus for A. testudo and its related species.

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