Dolichoderus tertiarius

Introduction

Dolichoderus tertiarius is an extinct ant species known only from Eocene Baltic amber, dating back approximately 44-49 million years. Workers measured 3-4mm in body length, making them small ants with the characteristic dolichoderine body plan: a smooth and shiny mesosoma, a node-like petiole with a short anterior cylindrical part, and a distinctively shaped propodeum with a flat dorsal surface and deeply concave posterior section . These ants were among the most common ant species in Late Eocene ambers, found across Baltic, Bitterfeld, Rovno, and Scandinavian amber deposits . Unlike living ant species, D. tertiarius exists only as preserved fossils in ancient tree resin - they cannot be kept as living colonies. This species represents an important piece of ant evolutionary history, showing us what dolichoderine ants looked like during the Eocene epoch when Earth's climate was much warmer than today. The presence of isolated pits on the cheeks and sometimes occipital head angles is a distinguishing feature observed in fossil specimens .