Eulithomyrmex

Eulithomyrmex is an extinct genus of ant in the formicid subfamily Agroecomyrmecinae. The genus contains two described species, Eulithomyrmex rugosus and Eulithomyrmex striatus. Eulithomyrmex is known from a group of Late Eocene fossils which were found in North America.

== History and classification == When described the genus Eulithomyrmex was known from over forty separate fossils preserved as impressions in fine shales of the Florissant formation in Colorado. The formation is composed of successive lake deposits which have preserved a diverse assemblage of insects. The insects and plants suggest a climate similar to modern Southeastern North America, with a number of taxa represented that are now found in the subtropics to tropics and confined to the Old World. When Eulithomyrmex was described, the Florissant formation was considered to be Miocene in age, based on the flora and fauna preserved. Successive research and fossil descriptions moved the age older and by 1985 the formation had been reassigned to an Oligocene age. Further refinement of the formation's age using radiometric dating of sanidine crystals has resulted in an age of 34 million years old. This places the formation in the Eocene Priabonian stage.