Morphology and Putative Ecology of Eocene Ant Agroecomyrmex duisburgi (Hymenoptera: Formicidae: Agroecomyrmecinae)

Abstract

Agroecomyrmecinae is a poorly-known subfamily of ants that includes just two extant genera and species, Tatuidris tatusia Brown et Kempf, 1968, a leaf-litter dweller from the Neotropics, and Ankylomyrma coronacantha Bolton, 1973, an arboreal inhabitant from West Africa. Two Agroecomyrmecinae genera have been described from Eocene fossils: Agroecomyrmex Wheeler, 1910 found in European amber (Baltic and Bitterfeld), and Eulithomyrmex Carpenter, 1935 found in North American shale (Florissant). There are published records of just seven specimens of Agroecomyrmex duisburgi (Mayr, 1868), the sole member of its genus. We found four additional A. duisburgi specimens, three from Baltic amber and one from Rovno (Ukraine) amber of similar age (Priabonian stage, 37.8–33.9 Ma). This increases number of known ant subfamilies in Rovno amber to 10, and indicates that Agroecomyrmecinae were distributed in the late Eocene on both the northern and southern coasts of the Paratethys Sea. Based on morphological features and the rarity of fossil remains, we suggest that Agroecomyrmex and Eulithomyrmex were most likely neither litter-dwelling nor arboreal, but were epigean species, living on the soil surface.