when described, "pachycondyla eocenica" was known from two fossil insects which are compression-impression fossils preserved in layers of soft sedimentary rock. along with other well-preserved insect fossils, the "p. eocenica" specimens were collected from layers of the lutetian messel pit world heritage site. the formation is composed of brown coals, oil shales, and bituminous shale, which preserved numerous insects, fish, birds, reptiles, and terrestrial mammals as a notable lagerstätten. the area is a preserved maar lake which initially formed approximately 47 million years ago as the result of volcanic explosions.