title: The making of a branching annelid: an analysis of complete mitochondrial genome and ribosomal data of Ramisyllis multicaudata.
abstract: Ramisyllis multicaudata is a member of Syllidae (Annelida, Errantia, Phyllodocida) with a remarkable branching body plan. Using a next-generation sequencing approach, the complete mitochondrial genomes of R. multicaudata and Trypanobia sp. are sequenced and analysed, representing the first ones from Syllidae. The gene order in these two syllids does not follow the order proposed as the putative ground pattern in Errantia. The phylogenetic relationships of R. multicaudata are discerned using a phylogenetic approach with the nuclear 18S and the mitochondrial 16S and cox1 genes. Ramisyllis multicaudata is the sister group of a clade containing Trypanobia species. Both genera, Ramisyllis and Trypanobia, together with Parahaplosyllis, Trypanosyllis, Eurysyllis, and Xenosyllis are located in a long branched clade. The long branches are explained by an accelerated mutational rate in the 18S rRNA gene. Using a phylogenetic backbone, we propose a scenario in which the postembryonic addition of segments that occurs in most syllids, their huge diversity of reproductive modes, and their ability to regenerate lost parts, in combination, have provided an evolutionary basis to develop a new branching body pattern as realised in Ramisyllis.
authors.affiliation: Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Aguado
authors.affiliation: Museum and Art Gallery of the Northern Territory, GPO Box 4646, Darwin, N.T., Australia.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Glasby
authors.affiliation: School of Biological Sciences, Washington State University, Pullman, Washington 99163-4236, USA.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Schroeder
authors.affiliation: 1] Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, Talstraße 33, D-04103 Leipzig, Germany [2] Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Weigert
authors.affiliation: Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, Talstraße 33, D-04103 Leipzig, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Bleidorn
mesh_terms: D000818:Animals; D000845:Annelida / Q000033:anatomy & histology / Q000145:classification / Q000235:genetics*; D001425:Bacterial Outer Membrane Proteins; D050259:Genes, Mitochondrial; D016678:Genome; D054629:Genome, Mitochondrial; D023281:Genomics; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D012270:Ribosomes / Q000235:genetics*
chemical_list: D001425:Bacterial Outer Membrane Proteins; C418865:membrane protein, 75kDa