The Unexplored Biodiversity of ‘Glacier Fleas’ (Hexapoda: Collembola): Taxonomy, Distribution and Ecology in the European Alps and Apennines

Springtails (Hexapoda: Collembola) are unique among Alpine arthropods for including cryophilic species, able to live in contact with glacial ice, the so-called ‘glacier fleas’. Despite being historically recorded, their taxonomy and distribution are largely unknown. In this article, we present the first comprehensive study of ice-dwelling springtails (family Isotomidae) of the European Alps and Apennines. Morphological and molecular analyses of two mitochondrial genes (cox1 and 16S) were performed after an extensive field sampling across 48 European sites. Five new species were identified and described on the Alps: Desoria orobica sp. nov., Vertagopus glacialis sp. nov., V. psychrophilus sp. nov., V. glacieinigrae sp. nov. and V. fradustaensis sp. nov., together with the already known D. saltans and V. alpinus. The evidence for two further new species was also reported, with the first occurrence of Gnathisotoma bicolor for the Alpine chain. Desoria calderonis occurs on the only glacier of the Apennines. Among the new species, V. glacialis and V. psychrophilus exhibit a wide range distribution, while the other species show a narrow endemic distribution. The study highlighted the unexplored diversity of Alpine ‘glacier fleas’ and their ecological and biogeographic interest, together with the conservation concern in the context of the present warming cycle.