Three new species of Tetracanthella (Collembola, Isotomidae) from western Europe

Three new species of Tetracanthella Schött, 1891 (Collembola, Isotomidae) are described in this paper: T. bichaeta n. sp. from Swiss Alps, T. corsica n. sp. from Corsica and T. fusca n. sp. from French Pyrenees. T. bichaeta n. sp. is characterised by a tergite macrochaetotaxy formula 2,2/2,2,2 and the presence of two dorsal clavate tenent hairs on tibiotarsi of first pair of legs; this unique combination of characters questions the validity of the current delimitation between pilosa- and cassagnaui-groups in the genus. T. corsica n. sp. belongs to the wahlgreni-group, where it is isolated by a combination of chaetotaxic characters and by the remarkable shape of the papillae of its outer anal spines. T. fusca n. sp. of the pilosa-group is closely related to T. similis Deharveng, 1987 described from Alpes-Maritimes (SE France), from which it differs by shorter tergite s-chaetae and smaller dorsal plates on Abd. IV.