The temperature experienced by micro-invertebrates in extreme environments (such as those of Antarctica) is a pivotal parameter regarding these animals' ecology and physiology. However, at present, detailed knowledge of microhabitat physical conditions in Antarctica is limited, as well as being biased towards sub-Antarctic and Maritime Antarctic regions. To better understand the temperature conditions experienced in the microhabitats of Continental Antarctica by the native microfauna, we recorded temperatures year round in ponds and soils in an area of the Victoria Land coast and compared these measurements with air temperature data from the closest automatic weather station. We identified an important difference in temperature dynamics between the air, soil and pond datasets. Ponds were the warmest sites overall, differing by up to 7.5°C in comparison with the air temperature due to their greater thermal capacity, which also drove their patterns of freeze-thaw cycles and mean daily thermal excursion.

A new marine tardigrade of the genus Tanarctus is described from Japan. Tanarctus diplocerus sp. nov. was collected from Shimabara Bay, Kumamoto and Tanabe Bay, Wakayama. It is characterized by simple leg IV appendages, the lack of the internal–external relation in the dorsal and ventral cirri and the lack of the club-shaped secondary clavae. The secondary sexual dimorphism of the primary clavae and probable two-digit juveniles of the new species are reported. The problematic terminology of the so-called ‘internal’ and ‘external’ cirri is also discussed. A taxonomic key for the species of Tanarctus is provided.

This study represents the first systematic investigation of long-term anhydrobiotic survival in tardigrades, rotifers and nematodes inhabiting mosses and lichens. Sixty-three different samples from public and private collections, kept dry for 9–138 years, were examined. Rotifers of the genus Mniobia and the eutardigrade Ramazzottius oberhaeuseri (hatched from eggs) were found alive from one of the samples (9 years old). These observations represent the longest record for rotifers in the anhydrobiotic state. For tardigrades, our results confirm previous reports on the upper limit of anhydrobiotic survival under atmospheric oxygen conditions. This study suggests the possibility that tardigrade eggs are able to withstand longer periods in anhydrobiosis than animals. Some problems related to the evaluation of long-term anhydrobiotic survival, such as contamination and chemical treatments of samples, are reported. The possible role of the microenvironment in which the anhydrobiotic animals are kept is discussed.