Austrocodrusgladiogeminus sp. n. is described from southernmost South America. It is a member of the primitive subfamily Austroserphinae (Hymenoptera, Proctotrupidae), which is distributed in Oceania and South America, and is characterized from other Austrocodrus species by its relatively larger body size, the presence of long and sword-shaped ovipositor sheaths, M arising very close and distal to 1cu-a, and Cu and m-cu joining at a distance equivalent to the length of 2cu-a. We consider this species to be a Gondwanan relict. It has southernmost distribution of any proctotrupid.
Keywords: Chile; Patagonia; Subantarctic Forest; endemism; morphology; taxonomy.