Unusual shallow-water boreal gastropod species associations at the Northern part of Arctic archipelago Novaya Zemlya

The fauna of the Barents Sea is the richest compared to other Arctic seas and is represented by a mixture of Arctic and boreal species, the distribution of which is believed to be due to the temperature conditions. In this study, this hypothesis was tested using data on the species composition of gastropods in the northern part of Novaya Zemlya, one of the coldest regions in the Barents Sea. Species associations with the predominance of the boreal species Lacuna vincta (Montagu, 1803) were found in the studied area; additionally, the fauna of gastropods was generally more similar to that of the boreal regions (White Sea and the Murman Coast) than the Arctic (fjords of Svalbard, Matochkin Shar (Novaya Zemlya), Franz Josef Land). The results obtained do not agree with the assumption about the effect of the temperature being the main factor determining the distribution of benthic communities in the Barents Sea. Two alternative hypotheses are proposed: either the influence of the Novaya Zemlya current as a corridor for the dispersal of species; or the existence of a glacier refugium off the coast of Novaya Zemlya where the shallow-water fauna could have survived the last glaciation.