title: DNA Taxonomy of Paranemertes (Nemertea: Hoplonemertea) with Spirally Fluted Stylets.
abstract: Of the 14 nominal species that are now or have ever been assigned to the genus Paranemertes Coe, 1901 , four have been reported to have stylets with a spirally fluted or braided appearance. Although differentiation in color patterns has been documented among species/populations, these nemerteans share similar external characters. Using the sequence datasets of mitochondrial cytochrome c oxidase subunit I (COI), 16S rRNA, and nuclear 28S rRNA genes of specimens from 14 localities of Canada, USA, Russia, Japan, and China, we analyzed the genetic differentiation and reconstructed the phylogenetic trees for these nemerteans. In conjunction with the external characters, we discuss their taxonomy and species delimitation. An analysis based on COI dataset showed high genetic variations among populations and even among worms from the same geographic area. The analyzed 111 individuals were assigned into seven networks by statistical parsimony analysis. The inter-network uncorrected p-distances ranged from 0.044 to 0.172 and the mean intra-network uncorrected p-distances varied from 0.001 to 0.005. With the exception of two networks that contain specimens from the East China Sea, all networks were well-supported by the results of Bayesian and neighbor-joining analyses on the COI data. Phylogenetic trees based on 16S rRNA and 28S rRNA datasets were basically similar to the COI trees, but specimens in some networks were merged into larger clades. Present molecular analyses support the validity of P. sanjuanensis and the synonymization of P. cylindracea with P. peregrina. Nemerteans previously recorded as P. peregrina may contain several species and sympatric speciation might have been occurred in this nemertean group.
authors.affiliation: 1 institute of Evolution & Marine Biodiversity, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Hao
authors.affiliation: 2 Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kajihara
authors.affiliation: 3 A.V. Zhirmunsky Institute of Marine Biology, Vladivostok 690041, Russia.|4 Far Eastern Federal University, Vladivostok, Russia.
authors.forename: Alexei V
authors.initials: AV
authors.lastname: Chernyshev
authors.affiliation: 5 Department of Zoology, Weber State University, 1415 Edvalson Street, Dept 2505, Ogden, UT 84408-2505, USA.
authors.forename: Robert K
authors.initials: RK
authors.lastname: Okazaki
authors.affiliation: 1 institute of Evolution & Marine Biodiversity, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
authors.forename: Shi-Chun
authors.initials: SC
authors.lastname: Sun
mesh_terms: D000818:Animals; D002965:Classification; D004247:DNA / Q000235:genetics*; D014644:Genetic Variation; D007448:Invertebrates / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny
chemical_list: D004247:DNA
keywords: DNA taxonomy; Nemertea; Paranemertes; genetic variation; phylogeny; sibling species; species delimitation; spirally fluted stylets; statistical parsimony network