Tetramorium albenae Salata, van Delft & Borowiec n. sp. (Hymenoptera, Formicidae) - a new inquiline ant species from the Balkan Peninsula

Tetramorium Mayr, 1855 is a worldwide distributed and hyperdiverse ant genus consisting of almost 600 taxa manifesting various life history strategies. Species of the Tetramorium inquilinum species-group represents one of the most extreme forms of parasitism and consist of degenerate workerless social parasites of several Tetramorium species. So far, its members have been recorded in the Palearctic from montane to alpine zones and reveal an interesting disjunction in host selection observed between eastern-Mediterranean and western-Mediterranean species. We describe a fifth member of the Tetramorium inquilinum species-group: Tetramorium albenae Salata, van Delft & Borowiec sp. n. The species morphologically differs from the remaining members of the group by the combination of the following characters: dense and erect pilosity of appendages and the whole body, smooth head sculpture, predominantly smooth anepisternum and katepisternum, lack of blunt teeth on propodeum, and presence of distinct carianae on the dorsolateral margins of the propodeum. Tetramorium albenae Salata, van Delft & Borowiec sp. n. was collected in a lowland olive grove, a site so far not associated with the Tetramorium inquilinum species-group, from a nest of Tetramorium kephalosi (a new host species for the group). The data presented in this paper provide new insights into the habitat preferences of the species of the Tetramorium inquilinum species-group and extend our knowledge on the potential host species of these parasites.