Tardigrades from Stelvio National Park, Central Alps (Italy)

Tardigrades have been collected in different habitats in an Alpine glacial valley (Val de la Mare, Stelvio National Park, Trentino, Italy), between 2200 and 2300 m a.s.l. Submerged mosses of streamlets (2 samples), turf (1 sample) and mosses on rocks (2 samples) have been considered. These habitats hosted a very rich and diversified tardigrade fauna. Particularly rich in tardigrades were the submerged mosses, which comprised 9 species of eutardigrades belonging to 3 different families and 8 genera. Worthy of note are the first record of Borealibius zetlandicus in Italy (a species with a boreo-alpine geographic distribution) and the presence of two kinds of eggs in Murrayon pullari, a situation reported only once in tardigrades. Within the turf, a poorly known habitat, we found only one species, a Macrobiotus belonging to the “hufelandi group”, certainly new to science. Mosses on rocks contained 8 species (three echiniscid heterotardigrades and 5 belonging to two families of eutardigrades), different from those found in the other two habitats; three of them (two Ramazzottius and one Hypsibius) are probably new to science. In total, 18 species have been identified, four of which are new to science, one new to Italy and three new to the Trentino province. These results confirm the biogeographic significance of many tardigrades and suggest the need for more specific studies on tardigrade distribution focused on high altitudes and glacial areas of the temperate zones, which should be considered as biogeographic islands.