Eotemnothorax gen. nov. (Hymenoptera: Formicidae) – A New Ant Genus from Late Eocene European Ambers

The new genus Eotemnothorax gen. nov. is established for the former Temnothorax Mayr, 1861 species from late Eocene European ambers. Workers and queens of Eotemnothorax gen. nov. resemble those of Temnothorax but differ by the absence of a medial clypeal carina; in addition, all queens and some workers examined have distinct simple spur on the meso- and/or metatibiae. Males of the described genus are clearly differentiated from Temnothorax by a filiform antennal funiculus without an apical club, a short scape, a short and thick 1st funicular segment, and a long and thin 2nd segment. At the same time, they are well distinguished from the males of the Leptothorax genus group (i.e., Leptothorax Mayr, 1855, Harpagoxenus Forel, 1893 and Formicoxenus Mayr, 1855) by 13-segmented antennae and subtriangular mandibles with a clearly defined masticatory margin with four sharp teeth. Temnothorax gracilis (Mayr, 1868), T. petiolatus (Mayr, 1868), T. glaesarius (Wheeler, 1915), T. longaevus (Wheeler, 1915), T. hystriculus (Wheeler, 1915), and T. placivus (Wheeler, 1915) are transferred to the genus Eotemnothorax. The neotypes of E. gracilis, E. hystriculus, E. petiolatus, and E. placivus are designated, and queen of E. gracilis is described for the first time. The following 12 species are described as new to science: Eotemnothorax armatum sp. nov., E. balticus sp. nov., E. foveocephalus sp. nov. , E. groehni sp. nov. E. khomychi sp. nov. , E. odontos sp. nov. , E. pedunculatus sp. nov. , E. perkovskii sp. nov. E. punctatus sp. nov. , E. rav sp. nov. , E. rectispinus and E. rhytidus sp. nov. A key to identification of Eotemnothorax gen. nov. species is compiled. I suggested that Eotemnothorax gen. nov. can be a putative ancestor of the genus Temnothorax + Leptothorax genus group. It is assumed that Eotemnothorax gen. nov. species were arboreal rather than epigean.