Abstract: Data on four species of the ant genus Tapinoma FÖRSTER, 1850 are presented. Three of these maintain permanent outdoor populations in Central Europe: the autochthonous T. subboreale sp.n., T. erraticum (Latreille, 1798) and T. nigerrimum (Nylander, 1856) which is a recently established neozoon in Germany. All three species can be safely separated on the individual level both in the female castes and in males by principal component analysis (PCA) and discriminant analysis (DA) of multiple morphometric characters. As the lectotype of T. ambiguum Emery, 1925 is heterospecific from a more northern species which had been constantly named T. ambiguum during the last 34 years, it was necessary to describe the latter as T. subboreale sp.n. The earlier synonymy of T. ambiguum with T. madeirense Forel, 1895 was confirmed on the basis of genital characters. The neotype of T. erraticum was fixed from a sample collected at the type locality. Tapinoma madeirense, known from Madeira and southern France, and T. subboreale sp.n. from Central and North Europe cannot be safely distinguished in the female castes but are clearly heterospecific concluded from male genital morphology. Workers of the four considered species show a strong allometry of some shape characters: Within the average intraspecific body-size range and given in per cent of the mean, the relative depth of posterior head excavation, of the metanotal groove and of the clypeal excision grow by 66.3%, 52.1% and 14.2% while relative head length falls by 13.6%. Removal of allometric variance in all shape characters and computation of these data in a Pca and a Da showed that worker morphologies of T. nigerrimum and T. erraticum differed independently from body size and, in conclusion, should also be independent from colony maturity.