Metalasius pumilus

Introduction

Metalasius pumilus is an extinct ant species known only from Baltic amber deposits dating to the Late Eocene epoch (37.2-33.9 million years ago). Workers are exceedingly small, measuring under 2mm in total length, making them among the smallest ants ever discovered . The species was originally described as Lasius pumilus by Mayr in 1868 before being transferred to the genus Metalasius in 2022 based on phylogenetic analysis . Workers are characterized by their lack of standing setae on the head and mesosoma, large compound eyes, and short, broad third antennal segment . The genus Metalasius is closely related to modern Lasius ants, representing an ancient lineage that went extinct millions of years ago.