Figure 7.11.1 Platydracus immaculatus (Mannerheim), dorsal habitus. 11.13.1 P. immaculatus, found crossing a driveway.

Platydracus immaculatus is a distinctive species that can be differentiated from other Staphylinina by a combination of a reddish head, red elytra without distinct and elongate dark spots, abdominal tergites with dense, paired patches of golden setae, and a non-metallic body (Fig. 7.11.1). Species of the P. cinnamopterus complex are similar in colouration but lack the distinct, paired patches of golden setae on the abdominal tergites.

This species is eastern in distribution: Ontario to North Carolina and west to Utah. Historically, it was quite commonly collected in ECAS but Platydracus immaculatus is now infrequently collected over much of its range. Although this is only subtly apparent in Map 17, the change is quite apparent after the early 1980’s.

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

In ECAS, P. immaculatus has been collected from February to November, with a relatively early peak in abundance during April-May.

Platydracus immaculatus is an open habitat species, occurring especially in stony areas with sandy soil. It can be collected from under stones, leaves, and other debris in old fields, savannah, edges of open wetlands, and the grassy areas along the shores of lakes and rivers. This species' range in Canada has always been restricted to the southern half of Ontario and Québec; however, P. immaculatus now seems to be rare in this area, with only 5 records from Canada after 1980 (Fig. 11.13.1). Further collecting in sandy, grassy habitat with stones is necessary to verify this species' apparent decline in Canada. Unlike many other species of Platydracus, P. immaculatus does not visit baited traps and is primarily captured by lifting debris or in pitfall traps. Platydracus immaculatus was generally known by the younger name P. vulpinus (Nordmann, 1837) until Smetana and Davies (2000) noted that the name immaculatus was older, and Herman (2001) adopted immaculatus as the valid name.