Limno-Terrestrial Tardigrada of Sub-Antarctic Islands—An Annotated Review

Research on the limno-terrestrial Tardigrada fauna of the Sub-Antarctic zone began almost 120 years ago. Here we present an overview of the literature data on the presence of tardigrades on sub-Antarctic islands, including the substrates on which they have been found. From 32 published sources, we found original data on the occurrence of 49 currently valid species on six sub-Antarctic islands/island groups. Of these, 9 species (18%) were originally described from this zone, another 13 species (26%) were described from Continental or Maritime Antarctica, almost half of these species (22 species—45%) were originally described from European localities, and the remaining 5 species (10%) were originally described from South America, Africa, or Australia. The validity of the records of individual species is discussed. We consider the presence of 29 species in the Sub-Antarctic to be doubtful. We ascertained a total of 90 combinations of species and islands or island groups. More than half (64%) of these will require confirmation in the future because we currently consider them doubtful. We can conclude that the tardigrade fauna of the sub-Antarctic islands is only very superficially known, and the occurrence of most species in this zone must be verified.