Taxonomic notes on the genus Chaetocladius (laminatus-group) (Diptera: Chironomidae, Orthocladiinae) II. Descriptions of C. bitusiki sp. n. and C. mantetensis sp. n., two relict species inhabiting cold alpine springs and streams

Abstract

Two new species of the genus Chaetocladius s. str. (C. bitusiki sp. n. and C. mantetensis sp. n.) are diagnosed and described based on material collected in some cold springs and small streams located at high altitude (1940–2300 m) in the High Tatra Mountains (Slovakia) and Eastern Pyrenees (France). The first one is described as male adult and pupal exuviae, while the second is described as male and female adults and pupal exuviae. Both C. bitusiki sp. n. and C. mantetensis sp. n. key to the laminatus-group for known Chaetocladius species on the basis of some characters found in the male adult: virga composed of three typical parts, inferior volsella sub-triangular to sub-circular, narrow to broad lobe, bearing or lacking a posterior marsupial-like pouch and an apical contrasting protuberance; gonostylus triangular, projecting posteriorly as a pointed or rounded apex. Taxonomic remarks on related Chaetocladius species, key to known male adults of the laminatus-group from Europe with comments on the ecology and geographical distribution of the new species are given. The two new species can be regarded as typical relict representatives of cold springs and streams at high altitudes. Such species could be used as relevant biological indicators of the global warming and local climate change.