ISSN 1911-2173


Tasgius ater (Gravenhorst 1802)

Figure 8.1.1 Tasgius ater (Gravenhorst), pronotum. 11.23.1 T. ater, dorsal habitus. 11.23.2 T. ater, from the basement of an old building.


Tasgius ater is easily recognized among the species of Tasgius and other all-black Staphylinina by the presence of smaller punctures between the normal, larger punctures of the head and pronotum (Fig. 8.1.1), and the wide spacing of these punctures; this produces an overall glossy appearance (Fig. 11.23.1).


This species is native to the Palearctic region but was first described by Gravenhorst (1802) from North America. Thus, it has been on the continent for a very long time and has since become widely distributed and established in ECAS (Map 29). Tasgius ater is newly recorded from Michigan, Ohio, and Vermont based on the study of 68 specimens.

Eastern Canada: ON, QC, NB, NS, PE, NL (All ECAS provinces)

Adjacent U.S.: MI, IN, OH, PA, NY, VT, NH, ME (All ECAS states)

Tasgius ater has been collected in ECAS from January to November, with an increase in abundance in July-August.



Tasgius ater is found under rocks and logs in a variety of environments including woodlands, near water, and in open fields. Specimens have also been collected under loose bark, in rotting grass piles, and on beaches. This species often occurs in human-disturbed areas in gardens and occasionally in dwellings (Fig. 11.23.2) but is less synanthropic than the other Tasgius occurring in ECAS.