HYMENOPTERA > APOCRITA | Aculeata > Formicidae > Formicinae > Lasiini

This species is almost identical to Lasius niger in terms of both size and general appearance, but prefers more natural habitats. Workers have a body length of 3.5 - 5mm, queens up to 9mm, and are mainly very dark brown to black in colour, although occasionally paler on the mesosoma. A distinguishing feature is that the clypeus has far less pubescence than Lasius niger, but that's pretty much the only visible difference between the species.

It is more shade-tolerant than Lasius niger and, whereas that species favours fairly open and dry, sunny sites, Lasius platythorax most often occurs in damp woodland where it typically nests in deadwood. It may also be found in wetlands and marshes, but is very unlikely to be found on open heathland or in urban environments such as gardens.    

Lasius platythorax has widespread but seemingly local distribution, with most records being from East Anglia and the south including Dorset, but very scattered elsewhere. It is, however, designated as a common ant species.

Unfortunately, I can't be certain about the individuals in these photos, so I've had to label them 'likely' as in Lasius cf.platythorax, with the location and woodland habitat having a fairly significant bearing on the identity.