It is shown that the name “Leptothorax nylanderi” as used by all earlier Russian authors, is a misidentification. The species distributed throughout East Europe and the Caucasus is really A. crassispinus Karawajew, 1926 (here revived from synonymy and stat. nov., and senior synonym of L. slavonicus Seifert, 1995 syn. nov.). There is a narrow zone of overlap of L. nylanderi and L. crassispinus in East Germany and West Poland but the situation in the Balkans needs further clarification.