Biogeographic patterns of tenebrionid beetles (Coleoptera, Tenebrionidae) on four island groups in the south Aegean Sea

New records on Tenebrionidae from four island groups of the southern Aegean (Santorini, Astypalaia, Nisyros and Kalymnos, with their satellite islets - 26 islands in total) allowed investigation of the biogeography of the taxon in the area. All tenebrionid records from small islets are new, with the exception of those from Pserimos and the satellite islets of Santorini. Chorological and nestedness analyses, species-area relationships and various measures of faunal similarity based on binary and quantitative data matrices were applied in order to explore biogeographic patterns. The Anatolian and east Mediterranean faunal elements dominate on the island groups of Kalymnos and Nisyros, with a considerable decrease on Astypalaia and Santorini, where circum-Mediterranean elements prevail. Analyses of faunal similarities clustered together the well defined island groups of Santorini and Astypalaia, while Kalymnos and Nisyros groups were clustered together rather vaguely. Astypalaia and Santorini were also the most nested island groups in the studied area. The biogeographic position of Astypalaia within the central Aegean islands is well supported by the data.