Eocenomyrma electrina, Dlussky & Radchenko, 2006

Dlussky, Gennady & Radchenko, Alexander, 2006, A new ant genus from the late Eocene European amber, Acta Palaeontologica Polonica 51 (3), pp. 561-567 : 564

Eocenomyrma electrina sp. nov.

Fig. 2 ; Tables 1, 2.

Derivation of the name: After Latin electrum —amber.

Holotype: ZMUC 328 , worker, complete specimen, leg. G.V. Henningsen, 16/5−1956.

Locality and horizon: Scandinavian Amber, late Eocene.

Diagnosis.—Total length ca. 3 mm. The new species is characterised by the following apomorphies: frontal carinae are short, quite strongly curved and merge with rugae, which surround antennal sockets, frons not very wide, but frontal lobes quite big and extended laterally; mesosoma short and robust, not constricted behind so that propodeum not much narrower than promesonotum, metanotal groove distinct, though not deep (seen in profile), promesonotum (seen from above) with weak but distinct promesonotal suture; propodeal spines of moderate length, wide and stout, rather blunt, slightly curved downwards, directed mainly backward and feebly divergent (seen from above); petiole only slightly longer than high, with distinct but not very long peduncle, petiolar node with rounded dorsum, without dorsal plate; lower (anterior) part of frons with not coarse longitudinal rugae, remainder part of head dorsum with longitudinal rugosity and reticulation; mesosoma with coarse reticulation, petiole and postpetiole with not coarse longitudinal rugae.

Eocenomyrma electrina differs from the all known Eocenomyrma species by its relatively short and robust mesosoma (AI 1.80 versus> 2.30 in other species) and much shorter petiole (PI 1.27 versus> 1.55 in other species). Additionally, it differs from E. elegantula by the body sculpture (see below); from E. rugosostriata it differs by the reticulated mesosoma, by the distinctly narrower frons (FI 0.39 versus 0.48–0.52), by the much more extended frontal lobes (FLI 1.24 versus 1.10–1.14), by the longer antennal scape (SI 1 0.71 versus 0.59), by reticulated sculpture of the mesosoma, by the smaller body size; for the differences between E. electrina and E. orthospina see above.

Figures

Fig. 2. Myrmicine ant Eocenomyrma electrina sp. nov., the holotype worker, ZMUC 328, from the Scandinavian Amber, late Eocene. A, B. Photograph in dorso−lateral view (A), and head and mesosoma in dorso−lateral view (B). C, D. Explanatory drawings, based on the original photographs; head, mesosoma, waist, and base of gaster in dorso−lateral view (C), and mesosoma, waist, and base of gaster in lateral view (D).