Taxonomic reassessment of the Indo-Pacific Scytosiphonaceae (Phaeophyceae): Hydroclathrus rapanuii sp. nov. and Chnoospora minima from Easter Island, with proposal of Dactylosiphon gen. nov. and Pseudochnoospora gen. nov.

Wilfred John E. Santiañez 1 , Erasmo C. Macaya 2 , 3 , Kyung Min Lee 4 , Ga Youn Cho 5 , Sung Min Boo 6  and Kazuhiro Kogame 7
  • 1 Department of Natural History Sciences, Graduate School of Science, Sapporo 060-0810, Japan
  • 2 Laboratorio de Estudios Algales (ALGALAB), Concepción, Chile
  • 3 Millennium Nucleus: Ecology and Sustainable Management of Oceanic Island (ESMOI), Coquimbo, Chile
  • 4 Department of Ecology and Genetics, Oulu 90014, Finland
  • 5 National Institute of Biological Resources, Incheon 22689, South Korea
  • 6 Department of Biology, Daejeon 305-764, South Korea
  • 7 Department of Biological Sciences, Faculty of Science, Sapporo 060-0810, Japan
Wilfred John E. Santiañez
  • Corresponding author
  • Department of Natural History Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
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  • Wilfred John E. Santiañez was formerly a research associate at the Marine Science Institute of the University of the Philippines where he worked on various aspects of seaweed biology, particularly seaweed diversity, ecology, and mariculture. He has a Master’s degree in environment and natural resource management from the University of the Philippines Open University and is now pursuing his PhD in Hokkaido University, Sapporo, Japan. His PhD research is focused on the taxonomy and molecular phylogeny of the brown algal family Scytosiphonaceae.
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, Erasmo C. Macaya
  • Laboratorio de Estudios Algales (ALGALAB), Departamento de Oceanografía, Casilla 160-C, Universidad de Concepción, Concepción, Chile
  • Millennium Nucleus: Ecology and Sustainable Management of Oceanic Island (ESMOI), Coquimbo, Chile
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  • Erasmo C. Macaya has been an assistant professor at Concepción University, Chile since 2010. He received a primary degree in marine biology and a Master’s in marine sciences from Universidad Catolica del Norte, Coquimbo, Chile. He obtained a PhD in marine biology from Victoria University, Wellington, New Zealand studying the dispersal patterns, connectivity, taxonomy and genetic diversity of the giant kelp, Macrocystis pyrifera. His research focuses on the different aspects of macroalgae, such as ecology, taxonomy and phylogeography.
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, Kyung Min Lee
  • Department of Ecology and Genetics, University of Oulu, Oulu 90014, Finland
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  • Kyung Min Lee earned a doctor of science in biology from Chungnam National University, Korea. Her PhD thesis focused on molecular systematics and biogeography of the brown algal family Scytosiphonaceae. In 2014, she moved to Ghent University, Belgium to study SNP discovery of Sargassum using RAD-sequencing as a postdoc for 1 year before she joined the Mutanen’s lab in University of Oulu, Finland as a postdoctoral researcher in February 2015. Her current work focuses on molecular species delimitation at genomic level and clarifying issues caused by DNA barcode-sharing between species, deep intraspecific splits in DNA barcodes, and introgression on DNA-based taxonomy.
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, Ga Youn Cho
  • National Institute of Biological Resources, Incheon 22689, South Korea
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  • Ga Youn Cho is a senior researcher in the National Institute of Biological Resources, Korea. Her research interests are biodiversity, phylogeography, taxonomy, and phylogeny of seaweeds.
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, Sung Min Boo
  • Department of Biology, Chungnam National University, Daejeon 305-764, South Korea
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  • Sung Min Boo is a professor emeritus at Chungnam National University. He was awarded a PhD by Seoul National University for the taxonomy of the family Ceramiaceae. His research includes the diversity and distribution of brown and red algae.
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and Kazuhiro Kogame
  • Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
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  • Kazuhiro Kogame is a Professor in the Faculty of Science, Hokkaido University, Japan. His research interests include taxonomy, phylogeny and life history of seaweeds.
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A new and putatively endemic species of Hydroclathrus, Hydroclathrus rapanuii, is described from the geographically isolated Easter Island in the southeastern Pacific based on morphological and molecular phylogenetic data. It is distinguished from other Hydroclathrus by thalli of unevenly furrowed thin membranes, and angular, block-like plurangial sori. Our phylogenetic analyses indicated that H. rapanuii is closely related to the generitype Hydroclathrus clathratus. We also report on the morphology and phylogeny of Chnoospora minima from Easter I. and elsewhere in the Indo-Pacific Ocean, noting the previously unreported presence of hollow portions in its medulla. Although not collected from Easter I., we herein propose the recognition of two new genera, Dactylosiphon gen. nov. and Pseudochnoospora gen. nov., based on our three-gene phylogeny and their known morphologies and anatomies. Dactylosiphon is based on the three species currently assigned to Colpomenia (C. bullosa, C. durvillei, and C. wynnei) that are genetically and morphologically (i.e. thalli with erect and finger-like tubes arising from a common saccate base) distinct from other members of Colpomenia. The monotypic genus Pseudochnoospora is represented by the decumbent, branching, and inter-adhesive species currently known as Chnoospora implexa. With the above proposals, we further increase the genus-level diversity of Scytosiphonaceae in the Indo-Pacific Ocean.

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