Diversity of the Sven Glacier (Spitsbergen, Petuniabukta) Tardigrades with a Potentially New Hypsibius Species (Hypsibiidae)

Tardigrades are known for their ability to adapt to living in extreme environments. One such environment in which these invertebrates are found is cryoconite holes – water-filled holes located on the surface of glaciers. In the present study, samples were obtained from cryoconite holes from the Sven glacier (Spitsbergen), and an analysis of the species composition of tardigrades was carried out. In the collected samples, four taxa were found: Fontourion glaciale (Zawierucha, Buda and Gąsiorek, 2020), Acutuncus mariae Zawierucha 2020, Grevenius cryophilus Zawierucha, Buda, Novotná Jaroměřská and Gąsiorek, 2020 and Hypsibius sp. (Svenbreen). Morphological analysis revealed that differences between our specimens of the Hypsibius sp. (Svenbreen) and already described representatives of the genus Hypsibius are very clear and suggest that ours belong to species new to science. However, due to lack of genetic data formal description of the new species is not possible in present paper.