%0 Journal Article %A Leonid H. Borysenko %T Description of a new genus of primitive ants from Canadian amber, with the study of relationships between crown ants and stem ants (Hymenoptera: Formicidae) %D 2016 %R 10.1101/051367 %J bioRxiv %P 051367 %X A detailed study of the holotype of Sphecomyrma canadensis Wilson 1985 from Canadian amber led to the conclusion that the specimen belongs to a genus here named Boltonimecia gen.nov. not previously described. The taxonomy of stem ants is not clearly understood; thus, in order to find the taxonomic position of the new genus, it was necessary to review the classification of stem ants in a study of their relation to crown ants. Lacking morphological data for traditional taxonomic approaches, a statistical study was done based on a morphometric analysis of antennae. The elongation of the scape is believed to play an important role in the evolution of eusociality in ants. However, this hypothesis has never been confirmed statistically. Our statistical analysis lends support to the view that the morphology of antennae reliably distinguishes stem ants from crown ants to determine whether a species belongs to one or the other group. This in turn may indicate the relationship exists between eusociality and the elongation of the scape. A review of Cretaceous records of ants is made and the higher classification of Formicidae with definitions of stem and crown groups is proposed. The newly obtained data are discussed focusing particularly on the origin, evolution and diversity of ants. %U https://www.biorxiv.org/content/biorxiv/early/2016/05/02/051367.full.pdf