Discoveries of new species on our little-known planet continue apace. The two known specimens of the impressively toothy Mystrium maren were collected in 2001 in Indonesia, and Jochen Bihn and Manfred Verhaagh just published a paper in Zootaxa describing this ant and another new species, M.leonie.
Source: J. H. Bihn & M. Verhaagh, 2007. A review of the genus Mystrium (Hymenoptera: Formicidae) in the Indo-Australian region. Zootaxa 1642: 1-12.
*update* Lead author Jochen Bihn writes about the paper on Trophallaxis Blog.