The organic-walled genera Resigella and Conicotheca (Protista, Foraminifera) at two Arctic deep-sea sites (North Pole and Barents Sea), including the description of a new species of Resigella

Abstract

We describe a new organic-walled foraminiferan species from the central Arctic Ocean (North Pole; 4,300 m water depth) and the Hakon Mosby Mud Volcano (HMMV) at the south-western Barents Sea continental margin (1,250 m depth) based on morphological features. Resigella polaris sp. nov. has a more or less transparent test, brownish-yellow in colour, less than 200 µm in length, with a length:width ratio of 3.1–4.7, and consisting of 3 droplet-shaped to oval chambers. Morphologically, it is intermediate between R. bilocularis and R. laevis, two species described from an extreme hadal site (Challenger Deep, 10,895 m depth) in the western Pacific Ocean. Another species present at the HMMV is R. moniliforme, the type species of Resigella, which has only been reported once from outside the Pacific. Additionally, our Arctic samples yielded a species of the diminutive, monothalamous, organic-walled genus Conicotheca that is remarkably similar to C. nigrans from the Challenger Deep, despite the considerable geographical and bathymetric gulf between the populations. The abundance of these species, and particularly of R. polaris sp. nov. at the North Pole, probably reflects the oligotrophic character of this ice-covered region.