This is one of twelve British ant species in the genus Myrmica. Individual workers of M. lobicornis tend to be more robust, rugose and darker reddish brown than other commonly encountered Myrmica; they can occasionally appear almost black although there is significant variation in colour. The available keys provide fairly clear characters for accurate determination of this species; the most pronounced feature is the conspicuous vertical flange at the bend of the antennal scape. Myrmica lobicornis is one of the least aggressive species of Myrmica and is unlikely to use its sting.
Myrmica lobicornis has a widely scattered distribution throughout England, Wales and Scotland, although curiously there is no record of this species from Ireland. This ant is found from Arctic Scandinavia south to southern Europe, and east to the Caucasus and central Asia.