Formica congerens Nylander, 1846 junior synonym of current valid taxon Formica lugubris Zetterstedt, 1838
Formica congerens Nylander, 1846a: 906 (w.) FINLAND. Palearctic.
Primary type information: Primary type material: lectotype worker (by designation of Seifert, 2021: 164). Primary type locality: Finland: Mjölön island near Helsinki (W. Nylander). Primary type depository: ZMHF. Secondary type information: Secondary type material: 4 paralectotype workers. Secondary type localities: same as for lectotype. Secondary type depository: ZMHF. Type notes: Radchenko, 2007: 36, cites 5 worker syntypes.