Staphylinus canaliculatus Fabricius, 1787: 221.
Drusilla canaliculata: Leach in Samuelle, 1819: 177. Drusilla cavicollis Casey, 1906: 322.
See Gusarov (2003) and Assing (2005 a, 2005 b) for further synonymies.
Diagnosis. Drusilla canaliculata can be easily separated from D. nearctica and D. ashei by its larger body size (significantly greater than 3.6 mm) and the broadly emarginate apex of the eighth tergite with serrate margin.
See: Casey (1906: 322) and Lohse (1974: 222–223) for descriptions; Assing (2006: 283) for habitus images (both sexes), apex of the eighth tergite (both sexes; females have a slightly more shallow emargination and lateral apices of emargination less produced), lateral view of the median lobe and spermatheca; Gusarov (2003: 112) for an illustration of the internal sac; Werner et al. (2007: 838) for a SEM of the copulatory piece and mechanism of sperm transfer.
Discussion. The type material of Staphylinus canaliculatus Fabricius, 1787, was not examined in this study because this is a widespread, well-documented species. Possibly due to a combination of wide distribution and aptery (Assing 2005 b), this species shows a range of subtle morphological variation and this may have contributed to the large number of synonyms.
Distribution. In North America, D. canaliculata is known mainly from the northeastern United States and provinces of Canada, including: Alaska (Casey 1906; but most likely not established, Gusarov 2003), Kentucky (Gusarov 2003), Massachusetts (FMNH), New York (Seevers 1978, Muona 1984, Gusarov 2003; personal observations), Pennsylvania (Seevers 1978), Ontario (Gusarov 2003), Prince Edward Island (Majka & Klimaszewski 2008), and Quebec (Gusarov 2003).