New species and distributional records of Aleocharinae (Coleoptera, Staphylinidae) from Ontario, Canada, with a checklist of recorded species Brunke, Adam J. Klimaszewski, Jan Dorval, Julie-Anne Bourdon, Caroline Paiero, Steven M. Marshall, Stephen A. ZooKeys 2012 186 119 206 PMPL http://species-id.net/wiki/Callicerus_obscurus Gravenhorst, 1802 Gravenhorst 1802 Insecta Staphylinidae Callicerus CoL Animalia Callicerus obscurus Coleoptera 29 148 Arthropoda species obscurus  Material examined. CANADA: ON:Hamilton Div., Hamilton, 15.v.1985, M. Sanborne, 1 (CNC); Huron Co., Brucefield, hedgerow, pitfall, 11.v.2009, A. Brunke, 1 (DEBU), same data except: 22.vi.2009, 1 (DEBU), Auburn, hedgerow, pitfall, 11.v.2010, A. Brunke, 1 (DEBU).  Distribution. Canada: ON; western Palaearctic ( Assing 2001; Gusarov 2003b). Adventive in Canada.  Comments.  Callicerus obscurusis recorded from Canada for the first time based on Ontario specimens mostly collected in agricultural hedgerows. Gusarov (2003b)first reported this species from North America in an online catalog of North American Athetinibased on specimens collected in Ontario (V. Gusarov, pers. comm). The 'undescribed Calliceruss.str.' from Ontario groundhog burrows mentioned by Ashe (in Newton et al. 2000) may in fact be this adventive species. Therefore, all Callicerusin North America may be introduced. Males of Callicerus obscurusare easily recognized by their extremely elongate antennomere 10. In North America, Callicerus obscurusmay be separated externally from Callicerus rigidicornisby the more elongate pronotum (Fig. 64).  Callicerus obscurusinhabits open and forested habitats in its native range and was suggested to be largely subterranean by Assing (2001)based on highly seasonal (mostly spring) surface activity and the low numbers of individuals captured in each collection event.