New ant species found

One weird ant suggests lost world of ancient ants living underground

7:30am, September 16, 2008
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1A new ant discovered in the Amazon looks so odd that scientists are choosing Latin names that playfully suggest the creature comes from Mars.

Yet the species Martialis heureka could help rewrite the history of ants on Earth.

Found in Brazil, the ant has a pale body and no eyes, says Christian Rabeling of the University of Texas at Austin. Its mouthparts stick out like sharp forceps and are longer than the rest of its head.

Its DNA may be even more interesting. Genetic analysis puts the new ant so far from other species that it deserves its own subfamily, Martialinae, Rabeling and his colleagues report in an upcoming Proceedings of the National Academy of Sciences. It’s the first new subfamily described for a living ant since 1923, the discoverers say.

“It’s an incredibly bizarre-looking ant morphologically, which for ant biologists is really exciting,” said Corrie Moreau, after seeing a picture. As an ant specialist at the FieldMuseum in Chicago, she says she can think of a few other species with each of the new ant’s peculiar features. But to find those rare traits combined in one species is unique, she says.

DNA analysis suggests that the odd ant’s lineage evolved earlier than any other living ant’s, Rabeling says.

That suggestion fits with a puzzling twist on ant history that has emerged from recent studies using DNA similarities to construct family trees. “Ants evolved from wasps — everybody agrees on that,” Moreau says. However, DNA-based family trees, including one she worked on, looked as if other specialized underground ants were the most ancient living lineage.

The new species could easily be another subterranean ant, Moreau speculates, since it has no eyes, a bleached color and extreme mouthparts. Adding it to the family tree strengthens the evidence that some of today’s underground ants really do come from ancient lineages.

Just how those lineages went underground isn’t clear, Moreau says. Perhaps the first ants really were subterranean specialists. Or perhaps ants first evolved above ground, but the only surviving descendants of those early ancestors come from lineages that literally went under.

Rabeling only has one specimen of the new ant so far. A coauthor found two other specimens before but they have since been lost. Subterranean ants are hard to find, so the researchers have called for more searches.

Naming a species based on a single specimen doesn’t strike Moreau as odd because the practice isn’t unusual. “The fact that a single ant ‘rediscovered’ in the rainforests of Brazil can tell us so much about the evolution of the ants highlights how little we know about the diversity of life on the planet,” she says.

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