title: Molecular Phylogeny of the Widely Distributed Marine Protists, Phaeodaria (Rhizaria, Cercozoa).
abstract: Phaeodarians are a group of widely distributed marine cercozoans. These plankton organisms can exhibit a large biomass in the environment and are supposed to play an important role in marine ecosystems and in material cycles in the ocean. Accurate knowledge of phaeodarian classification is thus necessary to better understand marine biology, however, phylogenetic information on Phaeodaria is limited. The present study analyzed 18S rDNA sequences encompassing all existing phaeodarian orders, to clarify their phylogenetic relationships and improve their taxonomic classification. The monophyly of Phaeodaria was confirmed and strongly supported by phylogenetic analysis with a larger data set than in previous studies. The phaeodarian clade contained 11 subclades which generally did not correspond to the families and orders of the current classification system. Two families (Challengeriidae and Aulosphaeridae) and two orders (Phaeogromida and Phaeocalpida) are possibly polyphyletic or paraphyletic, and consequently the classification needs to be revised at both the family and order levels by integrative taxonomy approaches. Two morphological criteria, 1) the scleracoma type and 2) its surface structure, could be useful markers at the family level.
authors.affiliation: Plankton Laboratory, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido 041-8611, Japan. Electronic address: y.nakamura@fish.hokudai.ac.jp.
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Plankton Laboratory, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido 041-8611, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Imai
authors.affiliation: Plankton Laboratory, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido 041-8611, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamaguchi
authors.affiliation: Department of Botany, National Museum of Nature and Science, Tsukuba 305-0005, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Tuji
authors.affiliation: CNRS, UMR 7144 & Université Pierre et Marie Curie, Station Biologique de Roscoff, Equipe EPPO - Evolution du Plancton et PaléoOcéans, Place Georges Teissier, 29682 Roscoff, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Not
authors.affiliation: Institute of Geology and Paleontology, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Noritoshi
authors.initials: N
authors.lastname: Suzuki
mesh_terms: D059001:Aquatic Organisms / Q000145:classification* / Q000166:cytology / Q000235:genetics; D056907:Cercozoa / Q000145:classification* / Q000166:cytology / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics
chemical_list: D012337:RNA, Ribosomal, 18S
keywords: 18S rDNA; Cercozoa; Phaeodaria; Rhizaria; single-cell PCR.