Credit: C. RABELING/UNIV. TEXAS, AUSTIN

This pale-yellow, eyeless creature is so bizarre that naturalist E. O. Wilson named it "the ant from Mars". Martialis heureka, a native of the Brazilian Amazon, is the founding member of a new subfamily of ants, which split off from the ant family tree early in its evolution.

"It could represent a relict species that retained some ancestral morphological characteristics," says discoverer Christian Rabeling, a graduate student in integrative biology at the University of Texas in Austin.

Ants evolved from wasps, so it was long assumed that any living ancestral species would be wasp-like and similar to a Cretaceous ant fossil discovered in the 1960s by Wilson and his colleagues. But Martialis stunned entomologists by looking completely different — genetic analysis confirms that it doesn't fit into the known taxonomy of ants (C. Rabeling et al. Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0806187105; 2008). It has long, delicate mouthparts, for munching soft invertebrates perhaps. And, compared with its sturdy front legs, the rear two sets are thin and spindly (the three other legs in the specimen shown were lopped off for DNA analysis). "It doesn't even look like it could walk at all," says Brian Fisher, an ant expert and curator of entomology at the California Academy of Sciences in San Francisco.