Annelids of the eastern Australian abyss collected by the 2017 RV ' Investigator' voyage Author Gunton, Laetitia M. Australian Museum Research Institute, Sydney, Australia laetitia.gunton@austmus.gov.au Author Kupriyanova, Elena K. Australian Museum Research Institute, Sydney, Australia & Macquarie University, Sydney, Australia Author Alvestad, Tom Department of Natural History, University Museum of Bergen, University of Bergen, Bergen, Norway Author Avery, Lynda Museums Victoria, Melbourne, Australia Author Blake, James A. https://orcid.org/0000-0001-8217-9769 Aquatic Research & Consulting, Duxbury, Massachusetts, USA Author Biriukova, Olga Museum and Art Gallery of the Northern Territory, Darwin, Australia Author Boeggemann, Markus University of Vechta, Vechta, Germany Author Borisova, Polina P. P. Shirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, Russia Author Budaeva, Nataliya Department of Natural History, University Museum of Bergen, University of Bergen, Bergen, Norway & P. P. Shirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, Russia Author Burghardt, Ingo Australian Museum Research Institute, Sydney, Australia Author Capa, Maria https://orcid.org/0000-0002-5063-7961 Department of Biology, University of the Balearic Islands, Palma, Spain Author Georgieva, Magdalena N. Natural History Museum, London, UK Author Glasby, Christopher J. https://orcid.org/0000-0002-9464-1938 Museum and Art Gallery of the Northern Territory, Darwin, Australia Author Hsueh, Pan-Wen Department of Life Sciences, National Chung Hsing University, Taichung City, China Author Hutchings, Pat Australian Museum Research Institute, Sydney, Australia & Macquarie University, Sydney, Australia Author Jimi, Naoto https://orcid.org/0000-0001-8586-3320 National Institute of Polar Research, Tachikawa, Tokyo, Japan Author Kongsrud, Jon A. Department of Natural History, University Museum of Bergen, University of Bergen, Bergen, Norway Author Langeneck, Joachim https://orcid.org/0000-0003-3665-8683 Department of Biology, University of Pisa, Pisa, Italy Author Meissner, Karin Forschungsinstitut Senckenberg, DZMB, Hamburg, Germany Author Murray, Anna https://orcid.org/0000-0002-1765-1286 Australian Museum Research Institute, Sydney, Australia Author Nikolic, Mark Museums Victoria, Melbourne, Australia Author Paxton, Hannelore https://orcid.org/0000-0001-7086-5219 Australian Museum Research Institute, Sydney, Australia & Macquarie University, Sydney, Australia Author Ramos, Dino https://orcid.org/0000-0002-4069-5383 Natural History Museum, London, UK Author Schulze, Anja Texas A & M University at Galveston, Galveston, TX, USA Author Sobczyk, Robert Department of Zoology of Invertebrates and Hydrobiology, University of Lodz, Lodz, Poland Author Watson, Charlotte Museum and Art Gallery of the Northern Territory, Darwin, Australia Author Wiklund, Helena Natural History Museum, London, UK & Gothenburg Global Biodiversity Centre and University of Gothenburg, Gothenburg, Sweden Author Wilson, Robin S. https://orcid.org/0000-0002-9441-2131 Museums Victoria, Melbourne, Australia Author Zhadan, Anna Biological Faculty, Lomonosov Moscow State University, Moscow, Russia Author Zhang, Jinghuai South China Sea Environmental Monitoring Centre, State Oceanic Administration, Guangzhou, China text ZooKeys 2021 2021-02-24 1020 1 198 http://dx.doi.org/10.3897/zookeys.1020.57921 journal article http://dx.doi.org/10.3897/zookeys.1020.57921 1313-2970-1020-1 CC23B8CE8C8E473CBD8C44E74252A33D F6561609F0F15EE8907C94528CA44E4F Phalacrostemma sp. nov. Diagnosis. Opercular lobes completely fused to each other. 12 pairs of (broken) outer golden paleae with pointed tips and compact thecae with straight margins. One pair of inner paleae, their blades smooth, amber-coloured with tapering tips. Eight pairs of robust and tapering opercular papillae, not extending to tip of outer paleae. Two pairs of flattened nuchal hooks, with poorly developed limbs on concave side. Tentacular filaments absent. Pair of buccal flaps present. One pair of short and robust palps, not extending to operculum. Thoracic segment 1 with one pair of long and tapering neuropodial cirri. Thoracic segment 2 with one pair of broad triangular lateral lobes. Eight pairs of dorsal branchiae on chaetigers 2-9. Four parathoracic chaetigers (3-6) bearing notopodia with robust non-retractile lanceolate chaetae interspersed with fine capillaries and neuropodia with thin lanceolate chaetae interspersed with fine short capillaries. Cauda lost. Remarks. This single specimen from 1761-1770 m is different from the specimens of P. timoharai as it has only 12 pairs of outer paleae (but many are broken), only one pair of inner paleae, two pairs of nuchal hooks and non-retractile lanceolate notopodial chaetae on parathoracic segments 3-6 (see Zhang et al. 2020 : fig. 10F). The specimen clearly belongs to a new species which was also confirmed by molecular data, but is too damaged to be described formally as a new species. Records. 1 specimen. Suppl. material 1: op. 128 (AM).