New data on spiders (Arachnida, Aranei) from the caves of Southwestern Siberia (Russia)

The paper reports six species of spiders from five families found in three caves located in the Altai Krai, Novosibirsk Oblast and Kemerovo Oblast of Russia. One troglophilic species, Improphantes improbulus (Simon, 1929) is recorded from Siberia and the Altai Mountains for the first time and another troglophile species, Metellina merianae (Scopoli, 1763) is recorded from the Novosibirsk Oblast for the first time. Improphantes improbulus, a species new to Siberia, is illustrated. The distribution and habitat preferences of all six species is discussed.