New records of deep-water ascidians (Ascidiacea: Stolidobranchia) from the Arctic Ocean, with comments on nomenclature and taxonomy

Three species of stolidobranch ascidians, Asajirus arcticus (Hartmeyer, 1923), Eugyrioides pedunculatus (Traustedt, 1886), comb. nov., and Kukenthalia borealis Hartmeyer, 1903 are recorded from the deep waters of the Arctic Ocean for the first time and are briefly described based on new material. The nomenclature of the involved ascidian taxa is discussed. It is shown that Eugyra Hancock, 1870 (Ascidiacea) is preoccupied by Eugyra Fromentel, 1857 (Anthozoa) and that the valid generic name for ascidians currently assigned to Eugyra is Eugyrioides Seeliger, 1907. The currently accepted subfamily name Polyzoinae Michaelsen, 1900 is invalid, as it is a junior synonym of Polystyelinae Herdman, 1886.