Known only from Madagascar, living lemurs have a shadowy history. Although molecular clocks suggest that these long-tailed, tree-dwelling primates appeared some 60 million years ago, fossils on the island date back only 40,000 years. Now paleontologists working in Pakistan have discovered 30-million-year-old teeth that resemble those of modern lemurs. The finding, reported in the 19 October issue Science, adds weight to the idea that lemurs may have originated in Asia rather than Africa.
In 1999, a team led by Jean-Loup Welcomme, a mammalian paleontologist at the University Montpellier II in France, was sifting through 5 tons of sediment in the Bugti Hills of central Pakistan looking for fossils. The researchers found thousands of rodent teeth and dozens of primate teeth, including some that strikingly resemble those of Cheirogaleus, the modern dwarf lemur. Although the team didn't find the tooth comb, a unique pattern of forward-pointing incisors that modern-day lemurs use for grooming or collecting resin, "the molars are extremely similar," team member Jean-Jacques Jaeger says. "Several dental traits are unusual and exclusively shared with lemurs."
Some paleontologists believe that lemurs evolved in Africa because of its proximity and rich record of primitive primates, although no lemur fossils have been discovered there. Jaeger says the new teeth from Pakistan mean that lemurs already diversified at least 30 million years ago, in Asia. "Now for the first time we have unequivocal paleontological evidence," he says. Jaeger believes that the lemurs probably got to Madagascar--which had separated from Asia about 88 million years ago--by riding on a small island that could have drifted from Asia to Africa and bumped into Madagascar.
If the teeth really did belong to lemurs, "this material is very important," says Christopher Beard, a paleontologist at the Carnegie Museum of Natural History in Pittsburgh who studies early mammals. Jaeger has "a really good chance of being right," says Beard--but he would like to see more fossils to back up the claim.