Theridion boesenbergi Strand, 1904 [snovačka Bösenbergova]

A total of 2906 specimens of spiders were collected in the mountain valley of the Chomutovka brook in the Krušné hory Mts. between years 2000 and 2020. A total of 336 species were found. According to their abundance and degree of threat, 86 of them belong to significant and rare species. Most significant species are: Achaeridion conigerum, Brommella falcigera, Clubiona corticalis, Dipoena erythropus, Ero tuberculata, Gonatium hilare, Neon levis, Nusoncus nasutus, Pardosa sordidata, Phycosoma inornatum, Talavera thorelli a Theridion boesenbergi.

During an arachnological survey in the Šumava National Park in 2016, two very rare spider species were discovered: Araneus saevus (Araneidae) was recorded for the second time, 45 years after its first report in the Czech Republic. The species is therefore no longer regionally extinct, and can be considered critically endangered. Theridion boesenbergi (Theridiidae) was recorded for the first time in the Šumava Mts. Ecological characterisation of the species is improved, being more psychrophilous than was previously expected. Almost all collected specimens of both species from the Czech Republic are deposited in the National Museum in Prague.