Articles | Volume 37, issue 1
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 Yasuhara, Kamila Sztybor, Tine L. Rasmussen, Hisayo Okahashi, Runa Sato, and Hayato Tanaka

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.