A Standoff Between Two Species of Millipedes on Tasmania On the Australian island of Tasmania, two species of millipedes maintain a mysterious standoff, according to a new study - separated by a 140-mile boundary they rarely cross. The boundary, just a few hundred feet wide in most places, is especially unusual because borders between species usually follow a natural geographic divide, like a ridgeline, said the study's author, Bob Mesibov, a millipede specialist at the Queen Victoria Museum and Art Gallery in Launceston, Tasmania. By contrast, this one cuts through hills and rivers. "It didn't follow a natural boundary in the geography at all," said Dr. Mesibov, who discovered and named both species in 2010. He describes his findings in the journal Zoo Keys. Dr. Mesibov spent two years mapping the species" range. The work involved more than 100 days in the field and visits to 350 sites in northwestern Tasmania. Abundant in their own territories, the two species of millipedes are difficult to tell apart. "They look like sister species," Dr. Mesibov said. It is not yet known how the millipedes maintain such a tight boundary over such a long stretch. That is research that Dr. Mesibov is leaving to other biologists, but he suspects that the two species have a biological arrangement. "It has nothing to do with the environment," he said. It's like a political thing between these two species. Meanwhile, he has gone back to his regular work of discovering millipede species. So far, he has named more than 100.