Five species of Tardigrada were found in two moss samples collected from the Hornsund area (Ariekammen, Spitsbergen) including one new to science. The new species, Isohypsibius karenae sp. n., differs from the other similar congeners mainly by having a different type of cuticular sculpture, a different macroplacoid length sequence, by the presence of lunules and cuticular bars under claws as well as by some morphometric characters. The current study increases the number of Isohypsibius species known from Svalbard to thirteen.
A new species, Chenophila nanseni sp. n., collected from covert quills of the barnacle goose Branta leucopsis (Anseriformes: Anatidae) in Svalbard (Spitsbergen) is described and female polymorphism is recorded in this species. In syringophilids this phenomenon was known only for representatives of the genus Stibarokris. The new species differs from the similar Ch. platyrhynchos by following features: in females of Ch. nanseni the anterior margin of the propodonotal shield is flat (vs. concave in Ch. platyrhynchos) and the lengths of idiosomal setae si, f2 and ag3 in Ch. nanseni are distinctly shorter than in Ch. plathyrynchos.
In polar regions, apart from tundra and glaciers, geothermally active areas with elevated temperatures are important elements of ecosystems. One such geothermally active region characterized by mosaic ecosystems and vast areas covered by recent lava fields is Iceland. The aim of our study was to explore the diversity of invertebrates inhabiting geothermally active lava fields in the Krafla area (Iceland). Eight bryophyte samples were collected from a warm surface, mainly from the steaming areas. We have found Nematoda, Rotifera, Tardigrada and Oribatida in the samples. Habitat analysis demonstrated there to be 12 bryophyte species (five liverworts and seven mosses). The diversity of bryophytes in a single sample ranged from one to six species. The most common bryophyte was Racomitrium lanuginosum (Hedw.) Brid. Four species of tardigrades were found, including one that was new. Pilatobius islandicus sp. nov. is described herein by morphological, morphometric and molecular approaches (COI, 28S rRNA, 18S rRNA). Oribatida mites were identified as two species (Malaconothrus monodactylus (Michael, 1888) and Camisia foveolata Hammer, 1955). The average density of invertebrates was 13.1 ind./g with a maximum of 40.8 ind./g calculated per dry material. The tardigrades found in our study belonged to herbivores, microbivores and omnivores, whereas the mites belonged to saprophages, which indicates complex trophic networks in geothermally active lava fields.
Water bears (Tardigrada) are known as one of the most extremophile animals in the world. They inhabit environments from the deepest parts of the oceans up to the highest mountains. One of the most extreme and still poorly studied habitats which tardigrades inhabit are cryoconite holes. We analysed the relation between area, depth, elevation and tardigrades densities in cryoconite holes on four glaciers on Spitsbergen. The mean (±SD) of cryoconite area was 1287.21±2400.8 cm2, while the depth was on average 10.8±11.2 cm, the elevation 172.6±109.66 m a.s.l., and tardigrade density 24.9±33.0 individuals per gram of wet material (n = 38). The densities of tardigrades on Hans Glacier reached values of up to 168 ind. cm3, 104 ind. g-1 wet weight, and 275 ind. g-1 dry weight. The densities of tardigrades of the three glaciers in Billefjorden were up to 82 ind. cm2, 326 ind. g-1 wet weight and 624 ind. g-1 dry weight. Surprisingly, although the model included area, depth and elevation as independent variables, it cannot explain Tardigrada density in cryoconite holes. We propose that due to the rapid melting of the glacier surface in the Arctic, the constant flushing of cryoconite sediments, and inter-hole water-sediment mixing, the functioning of these ecosystems is disrupted. We conclude that cryoconite holes are dynamic ecosystems for microinvertebrates in the Arctic.