Gesomyrmex gallicus

Introduction

Gesomyrmex gallicus is an extinct ant species known only from fossils preserved in Early Eocene amber from the Oise region of northern France. The species was described in 2023 based on four specimens found at the Le Quesnoy farm near Chevrière. Minor workers measured approximately 2.5-2.95 mm in body length, while major workers (soldiers) reached 4.7 mm. This species is distinguishable from all other Gesomyrmex species by its petiolar node having a sharp, acute dorsal margin rather than the rounded margin seen in related species, and it shares a distinctive nine-toothed mandible with the extinct G. hoernesi. The genus Gesomyrmex persists today with species living in warm, humid forests of Asia, making G. gallicus a window into European ecosystems during the warm Early Eocene period.