Repeatedly over the course of ant evolution, when called for by particular predatory lifestyles, mouthparts have morphed into a sort of awful bear-trap mechanism. Mandibles are held open with tremendous pent-up energy and slam shut on hapless prey when triggered. This modification is called a trap-jaw, and slightly different versions of it are present in various groups of carnivorous ants.
The single trap-jaw to emerge in the ant subfamily Formicinae (the same group as the carpenter ants) belongs to Myrmoteras, a tropical Asian insect that hunts springtails in the leaf litter. Our lab hosts a few individuals of Myrmoteras iriodum, recently collected from Borneo, and I spent a few hours photographing one last week. You can see the best shots here.
Of all the ants I’ve photographed, Myrmoteras seems the least real. It appears to have sprung to life from the caricatured pages of a comic book.