Chaetocladius berythensis sp. n., C. callauensis sp. n., C. guardiolei sp. n. and C. parerai sp. n., four relict species inhabiting glacial springs and streams in eastern Pyrenees and Lebanon (Diptera: Chironomidae)

Four new species of the genus Chaetocladius s. str. (C. berythensis sp. n., C. callauensis sp. n., C. guardiolei sp. n. and C. parerai sp. n.) are diagnosed and described based on material collected in some glacial springs and small streams located at high altitude (1800-2300 m). While C. berythensis sp. n. is described only as male adult from the upper basin of the Beirut River (Lebanon Mount, Western range, Mount Sannine), C. callauensis sp. n. C. guardiolei sp. n. and C. parerai sp. n. are described as male adult accompanied by descriptions of tentatively associated male pupal exuviae from the upper basin of the Mantet River and Soques stream (eastern Pyrenees, West France). Additional taxonomic notes including illustrations and brief descriptions of 10 taxa/species based on male adults, male pharate adults and pupal exuviae collected in glacial springs, peat bogs and streams located at high altitude are provided. On the basis of characters in the male adult, only C. berythensis sp. n. keys to the laminatus-group, which is reported for the first time from the Levantine sub-region. Based on the unusual shape of both inferior volsella and gonostylus, the four new Chaetocladius species each belong to local biogeographic elements: C. berythensis sp. n. to a ‘Levantine element’, while C. callauensis sp. n., C. guardiolei sp. n. and C. parerai sp. n. belong to a ‘Pyrenean element’. All of the four new species are considered to be relict representatives of glacial helocrenes and cold stenothermic streams. Such species may be biological indicators and biogeographic representatives of global warming and local climate change.