Formicoxenus nitidulus valid Finland. Palearctic.
Nylander, W. 1846b. Additamentum adnotationum in monographiam formicarum borealium Europae. Acta Societatis Scientiarum Fennicae 2:1041-1062.   127562

Formicoxenus nitidulus picea synonym of Formicoxenus nitidulus Luxembourg. Palearctic.
Wasmann, E. 1906. Zur Kenntniss der Ameisen und Ameisengäste von Luxemburg. Archives. Institut Grand-Ducal de Luxembourg (n.s.)1(1/2):104-124.   129630