AUTHOR=Eilertsen Mari Heggernes , Dahlgren Thomas G. , Rapp Hans Tore 

TITLE=A New Species of Osedax (Siboglinidae: Annelida) From Colonization Experiments in the Arctic Deep Sea

JOURNAL=Frontiers in Marine Science

VOLUME=7

YEAR=2020

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2020.00443

DOI=10.3389/fmars.2020.00443

ISSN=2296-7745

ABSTRACT=<p>Large parcels of organic matter in the deep sea, such as whale carcasses, harbor a very specialized fauna, most famously the bone-eating worms in the genus <italic>Osedax</italic> (Annelida, Siboglinidae). Although <italic>Osedax</italic> was first described only 15 years ago, there are already 26 described species from the Pacific, Atlantic, and Southern Oceans. The high discovery rate of new <italic>Osedax</italic> species indicates that there is still a lot of undescribed diversity. In this study we describe the most northerly species of <italic>Osedax</italic> to date, <italic>Osedax fenrisi</italic> sp. nov. from 73°N on the Arctic Mid-Ocean Ridge. We also present an updated molecular phylogeny of <italic>Osedax</italic> based on cytochrome oxidase subunit I and 18S rRNA, including all described species in the genus. The molecular results support that <italic>O. fenrisi</italic> sp. nov. is distinct from the previously known species of <italic>Osedax</italic>. Both morphological characters and the molecular phylogeny support the placement of <italic>O. fenrisi</italic> sp. nov. in clade V. The most striking morphological character shared with other described species in this clade (<italic>Osedax rubiplumus</italic>, <italic>Osedax roseus</italic>, and <italic>Osedax bryani</italic>) is the presence of long pinnules inserted on the outside of the palps. Nomenclatural act recorded in Zoobank. LSID: E55A5C87-0CB6-4146-B3D9-7E3B19B68628.</p>