Miocene ant-mealybug trophobiosis imaged with X-Ray micro-computed tomography

Amber is a remarkable preserving medium for Mesozoic and Cenozoic terrestrial biotas, but even when transparency is good, available viewing angles can be limited. The technique of X-ray micro-computed tomography allows inspection from any desired viewpoint and facilitates detailed anatomical measurements, avoiding parallax errors. Here, I show the use of this technique to study an extremely rare association of a Miocene ant (Acropyga glaesaria) trapped in resin while carrying a mealybug (Electromyrmococcus inclusus) with which to incubate a new colony. This is only a fourth known example of an Acropyga gyne holding a mealybug and the second recorded specimen of Electromyrmococcus inclusus. Measurements and other features of both ant and mealybug are consistent with the holotypes.