The Ants of the Genus Lasius (Hymenoptera, Formicidae) from Late Eocene European Ambers
Finds of the genus Lasius Fabricius in the Baltic, Bitterfeldian, Rovno, and Scandinavian Ambers (Late Eocene) are revised. Neotypes of L. pumilus Mayr, 1868 and L. punctulatus Mayr, 1868 are designated. A key to workers and gynes of Lasius species from the Late Eocene European ambers is compiled. All Lasius species from these ambers belong to the subgenus Lasius s. str. L. schiefferdeckeri Mayr, 1868 is one of most abundant ant species in the Late Eocene European ambers: it consists 15.2-19.5% of all ant specimens in Baltic Amber, 24.5% in Bitterfeldian Amber, 23.8% in Rovno Amber, and 23.6% in Scandinavian Amber of the examined collections. Based on the features of fossilization of this species, it is possible to assume that at least in part it constructed arboreal nests and made roads to aphids' colonies. The list of nine ant species found in syninclusions with L. schiefferdeckeri is provided.
Eocenomyrma ukrainica sp. n. and E. breviscapa sp. n., two new ant species of the extinct genus Eocenomyrma Dlussky et Radchenko, are described from the Rovno amber (Late Eocene, Priabonian, 34–38 Ma). E. ukrainica (described based on the male and gyne) differs from the previously known species of this genus by the shorter propodeal spines and by the sculpture of the head and mesosoma. E. breviscapa is described based on the single worker and differs from all known Eocenomyrma species by the punctated head, mesosoma and waist, by another shape of the petiole, by the shorter propodeal spines, and by the distinctly shorter antennal scape. Additional data on the record of E. rugosostriata (Mayr) and E. orthospina Dlussky et Radchenko is provided. A key for the identification of six known Eocenomyrma species is compiled. The character of the forewing venation of the male and gyne of E. ukrainica supports our idea about relation of this genus and the genus Temnothorax Mayr, and placing Eocenomyrma to the tribe Formicoxenini.
Two extinct species of the modern genus Tetramorium Mayr, T. paraarmatum sp. n. and T. kulickae sp. n., are described from the Baltic amber (Poland, ca. 37 Ma). This is the first record of the fossil species of this genus. Described species resemble recent Palaearctic species, and we preliminarily place them to the inerme and caespitum species groups, respectively. Findings of other, previously non-recorded and not described yet fossil Tetramorium species from the Middle (or possibly Early) Eocene and Miocene deposits of Europe and North America are discussed.
Electromyrmex wheeleri sp. n., which belongs to the extinct ant genus is described based on males from the Baltic and Bitterfeld Ambers (Priabonian stage, 33.9-37.2 Ma). Until now only one species of this specialized genus based on a single worker was described and taxonomic position of this genus in the subfamily Myrmicinae remains uncertain. By the forewing venation, males of E. wheeleri resemble Aphaenogaster Mayr, Messor Mayr and Pheidole Westwood, but diff ers from the fi rst two genera by the presence of Mayrian furrows, and from the latter one - by the antennal structure. On the other hand, males of this genus have a set of specialized characters, e. g., subcylindrical petiole, mandibles with an only single apical tooth, quite peculiar shape of mesosoma, etc. and the morphological features of the males of E. wheeleri also do not shed light on its systematic position.