Articles | Volume 37, issue 1
J. Micropalaeontol., 37, 139–148, 2018
J. Micropalaeontol., 37, 139–148, 2018

Research article 05 Jan 2018

Research article | 05 Jan 2018

Cold-seep ostracods from the western Svalbard margin: direct palaeo-indicator for methane seepage?

Moriaki Yasuhara1, Kamila Sztybor2, Tine L. Rasmussen2, Hisayo Okahashi1, Runa Sato1,3, and Hayato Tanaka4 Moriaki Yasuhara et al.
  • 1School of Biological Sciences and Swire Institute of Marine Science, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong SAR, China
  • 2CAGE – Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geology, UiT The Arctic University of Norway, Dramsveien 201, 9037 Tromsø, Norway
  • 3Department of Marine Biosciences, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan
  • 4Research Center for Marine Education, Ocean Alliance, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan

Abstract. Despite their high abundance and diversity, microfossil taxa adapted to a particular chemosynthetic environment have rarely been studied and are therefore poorly known. Here we report on an ostracod species, Rosaliella svalbardensis gen. et sp. nov., from a cold methane seep site at the western Svalbard margin, Fram Strait. The new species shows a distinct morphology, different from other eucytherurine ostracod genera. It has a marked similarity to Xylocythere, an ostracod genus known from chemosynthetic environments of wood falls and hydrothermal vents. Rosaliella svalbardensis is probably an endemic species or genus linked to methane seeps. We speculate that the surface ornamentation of pore clusters, secondary reticulation, and pit clusters may be related to ectosymbiosis with chemoautotrophic bacteria. This new discovery of specialized microfossil taxa is important because they can be used as an indicator species for past and present seep environments (

Short summary
Microscopic-sized fossils adapted to a particular chemosynthetic environment (such as cold methane seep) are poorly known. Here we report a new ostracod (small crustacean with high fossilization potential) species probably endemic to a cold methane seep environment. This new discovery is important because there is a wealth of microscopic-sized fossils in geological records and this species can be used as an indicator fossil for past cold methane seep environment.