New Species of Extinct Ant Genus Eocenomyrma Dlussky et Radchenko (Hymenoptera: Formicidae: Myrmicinae) from the Baltic Amber

A new species from the extinct ant genus Eocenomyrma, E. groehnisp. nov., is described based on worker from the Baltic amber (Late Eocene, Priabonian stage, 33.9–37.2 Ma). It the most resembles E. orthospina Dlussky et Radchenko, 2006 by shape of the propodeal spines and by the general appearance, but well differs from the latter by structure of the frontal carinae, which merging with the rugae that extend to the occipital margin; in contrary, the frontal carinae in E. orthospina are short, curve outwards and merge with the rugae, which surround antennal sockets. Additionally, entire head dorsum in E. groehni covered by the slightly sinuous longitudinal rugae, but in E. orthospina the only frons is with the not coarse longitudinal, slightly sinuous rugae, but the lateral parts of the head dorsum and occiput are with reticulation.