Revision of the genus Hantzschia (Bacillariophyceae) on Livingston Island (South Shetland Islands, Southern Atlantic Ocean)

Background and aims – The non-marine diatom flora of Livingston Island (South Shetland Islands, Maritime Antarctic Region) is currently under revision. One of the genera that still needed a revision is the genus Hantzschia, quite common in terrestrial habitats of the Antarctic Region. Methods – Using both Light Microscopical and Scanning Electron Microscopical techniques, the morphology of all Hantzschia taxa, present in the samples from Livingston Island, has been analysed. Each taxon is compared with all other possible similar Hantzschia taxa, known worldwide. Key results – Apart from the already known Hantzschia abundans and H. amphioxys f. muelleri, five new Hantzschia species are described: Hantzschia acuticapitata Zidarova & Van de Vijver sp. nov., H. confusa Van de Vijver & Zidarova sp. nov., H. hyperaustralis Van de Vijver & Zidarova sp. nov., H. constricta Van de Vijver & Zidarova sp. nov. and H. incognita Zidarova & Van de Vijver sp. nov. Conclusions – The obtained results confirm the presence of a typical and highly specific non-marine diatom flora in the Antarctic Region and contradict the generally accepted idea about the cosmopolitanism of diatoms.