Revision of type and non-type material assigned to the genus Orthocladius by Goetghebuer (1940–1950), deposited in the Royal Belgian Institute of Natural Sciences (Diptera: Chironomidae)

Abstract: Selected type and non-type material belonging to the genus Orthocladius van der Wulp, 1874 (Diptera: Chironomidae) sensu GOETGHEBUER (1940–1950), deposited in the Royal Belgian Institute of Natural Sciences (RBINS), originally comprising specimens dry pinned or stored in isinglass, were mounted on microscope slides and re-examined. Other chironomids present in the RBINS collection belonging to other genera were also examined. Fifty slides were prepared and identifi ed to species, or to generic level when the condition of the specimens did not allow species identifi cation. The following types, representing taxa formerly considered as nomina dubia, were examined and the concerned species are stated here as valid: Georthocladius collarti (Goetghebuer, 1941) comb. nov., Georthocladius scaturiginis (Goetghebuer, 1940) comb. nov., Lapposmittia succinea (Goetghebuer, 1942) comb. nov., Orthocladius (Euorthocladius) tolleti Goetghebuer, 1944 (new subgenus placement), Orthocladius (Orthocladius) timoni Goetghebuer & Timon-David, 1939, Pseudorthocladius hockaiensis (Goetghebuer, 1933). Orthocladius (Orthocladius) mitisi Goetghebuer, 1938, previously stated as junior synonym of Orthocladius (Orthocladius) glabripennis (Goetghebuer, 1921), is reinstated as valid species. The following new synonyms are proposed: Georthocladius (Georthocladius) collarti = Parachaetocladius retezati Albu, 1972: 19, syn. nov.; Cricotopus (Paratrichocladius) rufi ventris (Meigen, 1830) = Orthocladius franzi Goetghebuer, 1949, syn. nov.; Cricotopus (Paratrichocladius) skirwithensis Edwards, 1929 = Orthocladius nigritus Goetghebuer, 1938, syn. nov. = Paratrichocladius spiesi Ashe & O’Connor, 2012; Hydrobaenus distylus (Potthast, 1914) = Orthocladius antennalis Goetghebuer, 1944, syn. nov. Lectotypes of Orthocladius collarti Goetghebuer, 1941, Orthocladius antennalis Goetghebuer, 1944, Orthocladius timoni Goetghebuer & Timon-David, 1939, and Orthocladius hockaiensis Goetghebuer, 1933 are designated. Non-type material assigned to Orthocladius was also mounted on slides and identifi ed. Although a list of the non-Orthocladius taxa is also provided, no taxonomic changes are proposed for the latter.

Key words: Diptera, Chironomidae, chironomids, Orthocladius, museum, synonyms, taxonomy