title: Placement of the unclassified Cyranomonas australis Lee 2002 within a novel clade of Cercozoa.
abstract: Two heterotrophic flagellate strains were isolated from marine sediment samples off eastern Canada and Korea. These new isolates are indistinguishable by light microscopy from the unclassified protist Cyranomonas australis. The organisms are ovoid-shaped cells, 3.5-6μm long, laterally compressed, and somewhat flexible. They have two unequal flagella, about 1.1-2.5 times body length. Typically, the cells show a gliding motility and do not exhibit any amoeboid form or pseudopodia. 18S rDNA phylogenies clearly indicate that the isolates can be assigned to the taxon Filosa, within Cercozoa. The isolates are closest to an environmental sequence (CYSGM-16; 99% identity). Cyranomonas, CYSGM-16, and uncultured eukaryote RM1-SGM46 form a clade with strong statistical supports, here called novel clade CU (Cyranomonas plus Uncultured eukaryotes). This clade may be sister to the order Marimonadida. The novel clade CU and the Marimonadida have been detected only in marine habitats. Our findings suggest that C. australis may not belong to any previously described family within Filosa and Cercozoa.
authors.affiliation: Department of Urban Environmental Engineering, Kyungnam University, Changwon, Republic of Korea.
authors.forename: Won Je
authors.initials: WJ
authors.lastname: Lee
authors.affiliation: Department of Oceanography and Kyungpook Institute of Oceanography, School of Earth System Sciences, Kyungpook National University, Daegu, Republic of Korea. Electronic address: jongsoopark@knu.ac.kr.
authors.forename: Jong Soo
authors.initials: JS
authors.lastname: Park
mesh_terms: D002170:Canada; D056907:Cercozoa / Q000145:classification* / Q000166:cytology / Q000235:genetics / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D056910:Republic of Korea; D012689:Sequence Homology, Nucleic Acid
chemical_list: D012337:RNA, Ribosomal, 18S
keywords: Cercozoa; Cyranomonas; Marine sediment; Protist; Taxonomy; Unclassified Filosa